Trying to understand tcc lockup and how the overdrive works

Trying to understand tcc lockup and how the overdrive works

Postby Bread Van [OP] » November 14th 2012, 12:22am

Hey guys. I'm pretty new to automatic transmissions and know there is a lot of great knowledge here.

I'm looking for a guide/tutorial on how the 4L60E operates. Specifically what overdrive does and what/when/how TCC lockup occurs. Just so I know what my van is doing and can verify it is operating as it should.

As I was driving my loaded van home last night over hilly highways (without radio on for a change) I noticed the van seems to have a couple different drive options. :driving:

Here is what prompted the question:

For each of these first two "shifts" I either don't change my position on the accelerator or I push it down only very gently.
I begin cruising flat at 70ish MPH, I come upon a hill and the van seems to do a little shift, RPMs bump up a little. Is this the van coming out of TCC lockup?

As the hill gets steeper I get another little shift and the RPMs bump up a little more. Is this the van coming out of OD. I've always been under the impression that OD is somewhat equivalent to 4th gear. So at this point I'm assuming I'm in 3rd gear? Right?

All the while this is happening I'm losing speed because these are real hills and I'm driving mostly between 4000 and 7000' elevation. So...If I want to keep my speed up the push the accelerator harder, big change in position. Then the van does an obvious downshift and the RPMs jump quite a bit, the motor ROARS...it seems almost as if it's jumping right into 2nd gear. I don't like to run the van like this unless I have to for some reason like passing when a rare uphill passing lane is available.


Do I have this all right?

I have more questions but will leave it there for now. Just point me in the direction of good, straightforward (as opposed to super techy) resources on how the 4L60E with TCC lockup is supposed to work and I can try to be more specific.
Original Poster [OP]
User avatar
Bread Van
250k+ Miles
250k+ Miles
Firing on 5 Cylinders (L1)
Firing on 5 Cylinders (L1)
Years of Membership: Bread Van has been a member for 10 full yearsBread Van has been a member for 10 full yearsBread Van has been a member for 10 full yearsBread Van has been a member for 10 full yearsBread Van has been a member for 10 full yearsBread Van has been a member for 10 full yearsBread Van has been a member for 10 full yearsBread Van has been a member for 10 full yearsBread Van has been a member for 10 full yearsBread Van has been a member for 10 full years
Posts: 514
Topics: 36
Images: 0
Joined: March 2010
Alias (AKA): mapper
Van Model Year: 2003
Van Make/Model: Chevrolet Astro
Extra Info: AWD 2 inch lift

  • Similar topics
    Replies
    Views
    Author
  • P0740 and transmission acting wierd, went away at the shop..
    by thesigma » September 16th 2020, 3:59pm in Automatic
    12 Replies
    470 Views
    Last post by thesigma View the latest post
    September 29th 2020, 3:14pm
  • P0758 and crunchies
    by gnarballs » September 25th 2020, 6:03am in Automatic
    4 Replies
    208 Views
    Last post by gnarballs View the latest post
    November 5th 2020, 3:56am
  •  
    5
    55
    Last post by AstroSafari.com View the latest post
    March 1st 2021, 1:21am

Re: Trying to understand tcc lockup and how the overdrive wo

Postby chevymaher » November 14th 2012, 12:28am

Yes that is what is happening.

I live on ridiculously steep hills. Mine did that. I tuned it because it was a joke. That is what started my hot rodding my van because it ran so good after that. Believe me I never would have if it would have climbed 2 hills around here. I would have left it stock forever.
Image
User avatar
chevymaher
Team Leader
Team Leader
Firing on 8 Cylinders (L7)
Firing on 8 Cylinders (L7)
Years of Membership: chevymaher has been a member for 10 full yearschevymaher has been a member for 10 full yearschevymaher has been a member for 10 full yearschevymaher has been a member for 10 full yearschevymaher has been a member for 10 full yearschevymaher has been a member for 10 full yearschevymaher has been a member for 10 full yearschevymaher has been a member for 10 full yearschevymaher has been a member for 10 full yearschevymaher has been a member for 10 full years
Posts: 14239
Topics: 90
Images: 94
Joined: November 2010
Gender: Male
Alias (AKA): chevymaher
Van Model Year: 1994
Van Make/Model: GMC Safari
Extra Info: SLE RWD Mercruiser

Re: Trying to understand tcc lockup and how the overdrive wo

Postby Bread Van [OP] » November 14th 2012, 12:54am

I found this which is helpful to a noob like me:
http://autorepair.about.com/cs/troubles ... 61701a.htm


Maher, it seems I'm on the same page as you. I don't like how it drops out of TCC lockup so quick. I'd rather it just go from 4-3 when it needs to...At least that's what I'm thinking right now...but I have more to learn. Also it seems this can be adjusted with the proper equipment :shifty: ...more to learn
Original Poster [OP]
User avatar
Bread Van
250k+ Miles
250k+ Miles
Firing on 5 Cylinders (L1)
Firing on 5 Cylinders (L1)
Years of Membership: Bread Van has been a member for 10 full yearsBread Van has been a member for 10 full yearsBread Van has been a member for 10 full yearsBread Van has been a member for 10 full yearsBread Van has been a member for 10 full yearsBread Van has been a member for 10 full yearsBread Van has been a member for 10 full yearsBread Van has been a member for 10 full yearsBread Van has been a member for 10 full yearsBread Van has been a member for 10 full years
Posts: 514
Topics: 36
Images: 0
Joined: March 2010
Alias (AKA): mapper
Van Model Year: 2003
Van Make/Model: Chevrolet Astro
Extra Info: AWD 2 inch lift

Re: Trying to understand tcc lockup and how the overdrive wo

Postby chevymaher » November 14th 2012, 1:08am

Mine didn't come out of lock up or down shift. Untill I gas it enough it downshifts completely. Then your accelerating like crazy. The little motor does well if it tuned for power and not emissions. This was before the rebuild.
Now it just lugs along pretty much anywhere. 35 mph and a monster steep hill I go to 3rd. The hill before my house that started it all. Most cars are floored up that hill or they drop to 20 mph. It is a tractor pull hill, LOL.
Image
User avatar
chevymaher
Team Leader
Team Leader
Firing on 8 Cylinders (L7)
Firing on 8 Cylinders (L7)
Years of Membership: chevymaher has been a member for 10 full yearschevymaher has been a member for 10 full yearschevymaher has been a member for 10 full yearschevymaher has been a member for 10 full yearschevymaher has been a member for 10 full yearschevymaher has been a member for 10 full yearschevymaher has been a member for 10 full yearschevymaher has been a member for 10 full yearschevymaher has been a member for 10 full yearschevymaher has been a member for 10 full years
Posts: 14239
Topics: 90
Images: 94
Joined: November 2010
Gender: Male
Alias (AKA): chevymaher
Van Model Year: 1994
Van Make/Model: GMC Safari
Extra Info: SLE RWD Mercruiser

Re: Trying to understand tcc lockup and how the overdrive wo

Postby Bread Van [OP] » November 14th 2012, 5:04am

:D

Interesting. Mine will definitely do 2 little shifts before downshifting. I just didn't know if it was coming out of lockup before shifting out of OD... Now I got a little educated I realize that it HAS to come out of lockup to shift.

So here's my next question. It seems lockup only occurs in 3 and 4 so when I drive in town at say 35-40 mph how does the trans normally go

1-2-3-lockup
OR
1-2-3-OD-unlocked.
:confused:
I guess I'm confused about when lockup actually engages. Remember, up to recently, I was a manual trans guy so I ALWAYS knew what gear it was in. Sometimes the auto has me wondering where it sits

Like, for example, does it come out of lockup everytime I let off the gas? My van seems to do some amount of engine braking (as opposed to full neutral freewheeling) on long downhills...is that just from the trans fluid, or are gears actually engaged (lockup)?
Original Poster [OP]
User avatar
Bread Van
250k+ Miles
250k+ Miles
Firing on 5 Cylinders (L1)
Firing on 5 Cylinders (L1)
Years of Membership: Bread Van has been a member for 10 full yearsBread Van has been a member for 10 full yearsBread Van has been a member for 10 full yearsBread Van has been a member for 10 full yearsBread Van has been a member for 10 full yearsBread Van has been a member for 10 full yearsBread Van has been a member for 10 full yearsBread Van has been a member for 10 full yearsBread Van has been a member for 10 full yearsBread Van has been a member for 10 full years
Posts: 514
Topics: 36
Images: 0
Joined: March 2010
Alias (AKA): mapper
Van Model Year: 2003
Van Make/Model: Chevrolet Astro
Extra Info: AWD 2 inch lift

Re: Trying to understand tcc lockup and how the overdrive wo

Postby Bread Van [OP] » November 14th 2012, 5:07am

BUT, it seems to need a little throttle to fully "engage" if I'm trying to maintain 45-50 mph on a flat city street/parkway...when I pulse the accelerator the engine revs ever so slightly before feeling like it is dropping into gear...as if it was "unlocked" or freewheeling and needs a little gas and a split second to "relock"
Original Poster [OP]
User avatar
Bread Van
250k+ Miles
250k+ Miles
Firing on 5 Cylinders (L1)
Firing on 5 Cylinders (L1)
Years of Membership: Bread Van has been a member for 10 full yearsBread Van has been a member for 10 full yearsBread Van has been a member for 10 full yearsBread Van has been a member for 10 full yearsBread Van has been a member for 10 full yearsBread Van has been a member for 10 full yearsBread Van has been a member for 10 full yearsBread Van has been a member for 10 full yearsBread Van has been a member for 10 full yearsBread Van has been a member for 10 full years
Posts: 514
Topics: 36
Images: 0
Joined: March 2010
Alias (AKA): mapper
Van Model Year: 2003
Van Make/Model: Chevrolet Astro
Extra Info: AWD 2 inch lift

Re: Trying to understand tcc lockup and how the overdrive wo

Postby Shad0wXCalibur » November 14th 2012, 7:33am

My van does that same thing around 45-50 mph. Doesn't lock up TCC unless I push in the gas a little then I can back off the pedal some. It's annoying. And yes, it comes unlocked every time you let of the gas. I don't know why... I'd prefer to have it stay locked until it drops below a certain speed. My Saturn does this (with tachometer to verify) so why can't the van...
1987 Astro
2000 Safari
Shad0wXCalibur
Firing on 2 Cylinders (L2)
Firing on 2 Cylinders (L2)
Years of Membership: Shad0wXCalibur has been a member for 9 full yearsShad0wXCalibur has been a member for 9 full yearsShad0wXCalibur has been a member for 9 full yearsShad0wXCalibur has been a member for 9 full yearsShad0wXCalibur has been a member for 9 full yearsShad0wXCalibur has been a member for 9 full yearsShad0wXCalibur has been a member for 9 full yearsShad0wXCalibur has been a member for 9 full yearsShad0wXCalibur has been a member for 9 full years
Posts: 1225
Topics: 41
Joined: July 2011
Gender: Male
Alias (AKA):
Van Make/Model: GMC Safari
Extra Info: Lifted 2wd

Re: Trying to understand tcc lockup and how the overdrive wo

Postby chevymaher » November 14th 2012, 1:07pm

This is a subject that has been around and talked about before.

According to the past threads and information members found out they are only supposed to lock up in O.D.

But reality is different with mine. Put it in 3rd it does lock up in 3rd.
In O.D. it depends on how slowly you speed up. Idling along it locks in 3rd and then shifts to O.D. Then does it again.
Harder acceleration it skips lock up straight to 4rth then lock up

Now hang in there here where what your talking about comes in. Mine at 35-40 mph on the speedo. 30-35 mph real speed due to tire and gear changes.
O.D. Locks if you touch the gas and unlocks if you let off. I control it by avoiding that speed. Coast slower or just accelerate past it.

Going to my house there a 35 mph very steep grade hill. I use third to climb it. A flat then resumes the hill. So I have musical gears going on if I don't do it right. 3rd the flat 4rth with the lock-up spasm on that part. Then it just can't make up its mind which gear as you start up the lesser incline. With loud pipes it really makes the van sound like it blowing up.

So I leave room ahead of me on the big hill. Not a problem because most can barely climb it at all and they rocket off at the flatter less inclined section. I just give it enough gas to keep it in 3rd untill the second steep section. at the top I do 43 speedo mph 38 real speed in a 35 mph zone. I have to let off the gas to get it to shift to O.D. Then lightly gas it to get lock up.

These are the adventures of the computer trans I go through daily. With the mystery zone the trans don't know what to do.
Image
User avatar
chevymaher
Team Leader
Team Leader
Firing on 8 Cylinders (L7)
Firing on 8 Cylinders (L7)
Years of Membership: chevymaher has been a member for 10 full yearschevymaher has been a member for 10 full yearschevymaher has been a member for 10 full yearschevymaher has been a member for 10 full yearschevymaher has been a member for 10 full yearschevymaher has been a member for 10 full yearschevymaher has been a member for 10 full yearschevymaher has been a member for 10 full yearschevymaher has been a member for 10 full yearschevymaher has been a member for 10 full years
Posts: 14239
Topics: 90
Images: 94
Joined: November 2010
Gender: Male
Alias (AKA): chevymaher
Van Model Year: 1994
Van Make/Model: GMC Safari
Extra Info: SLE RWD Mercruiser

Re: Trying to understand tcc lockup and how the overdrive wo

Postby Bread Van [OP] » November 14th 2012, 3:37pm

chevymaher wrote:This is a subject that has been around and talked about before.

I'll see if I can find some of the threads
chevymaher wrote:According to the past threads and information members found out they are only supposed to lock up in O.D.
But reality is different with mine. Put it in 3rd it does lock up in 3rd.

This is where I get confused because I get engine braking in 1, 2, and 3...so it seems "engaged"
chevymaher wrote:In O.D. it depends on how slowly you speed up. Idling along it locks in 3rd and then shifts to O.D. Then does it again.
Harder acceleration it skips lock up straight to 4rth then lock up
Now hang in there here where what your talking about comes in. Mine at 35-40 mph on the speedo. 30-35 mph real speed due to tire and gear changes.
O.D. Locks if you touch the gas and unlocks if you let off. I control it by avoiding that speed. Coast slower or just accelerate past it.

So this Lock/unlock when pulsing the gas to cruise along is normal? That's my first concern because it seems a bit odd to a manual guy. I don't mind it too much but want to know if my gear is working.
chevymaher wrote:Going to my house there a 35 mph very steep grade hill. I use third to climb it. A flat then resumes the hill. So I have musical gears going on if I don't do it right. 3rd the flat 4rth with the lock-up spasm on that part. Then it just can't make up its mind which gear as you start up the lesser incline. With loud pipes it really makes the van sound like it blowing up.
So I leave room ahead of me on the big hill. Not a problem because most can barely climb it at all and they rocket off at the flatter less inclined section. I just give it enough gas to keep it in 3rd untill the second steep section. at the top I do 43 speedo mph 38 real speed in a 35 mph zone. I have to let off the gas to get it to shift to O.D. Then lightly gas it to get lock up.

I hear you. My big beef is when I try to use cruise control on freeways/interstates. With cruise engaged when I come on a hill (lots of those on my trips around here) the cruise applies gas hard enough to skip the little unlock, OD shifts and goes straight to a hard downshift sending RPMs through the roof.
chevymaher wrote:These are the adventures of the computer trans I go through daily. With the mystery zone the trans don't know what to do.

I just wish I knew what it was doing. I don't like the idea of shifting to 2 at freeway speeds.
From other reading I've done a Tech 2 scanner allows one to view all the programming tables and adjust them to better suit there needs. And, of course, read all the live data. I wish I could justify something like that, but can't. Looks like $450 is the going rate which isn't terrible since I need ABS diagnosis but not really justifiable to know what my trans is doing. After all...it works!
Original Poster [OP]
User avatar
Bread Van
250k+ Miles
250k+ Miles
Firing on 5 Cylinders (L1)
Firing on 5 Cylinders (L1)
Years of Membership: Bread Van has been a member for 10 full yearsBread Van has been a member for 10 full yearsBread Van has been a member for 10 full yearsBread Van has been a member for 10 full yearsBread Van has been a member for 10 full yearsBread Van has been a member for 10 full yearsBread Van has been a member for 10 full yearsBread Van has been a member for 10 full yearsBread Van has been a member for 10 full yearsBread Van has been a member for 10 full years
Posts: 514
Topics: 36
Images: 0
Joined: March 2010
Alias (AKA): mapper
Van Model Year: 2003
Van Make/Model: Chevrolet Astro
Extra Info: AWD 2 inch lift

Re: Trying to understand tcc lockup and how the overdrive wo

Postby chevymaher » November 14th 2012, 4:36pm

Bread Van wrote:From other reading I've done a Tech 2 scanner allows one to view all the programming tables and adjust them to better suit there needs. And, of course, read all the live data. I wish I could justify something like that, but can't. Looks like $450 is the going rate which isn't terrible since I need ABS diagnosis but not really justifiable to know what my trans is doing. After all...it works!



Welcome to the wonderful world of computers doing better. If it does anything wrong just go get your Vaseline.
Image
User avatar
chevymaher
Team Leader
Team Leader
Firing on 8 Cylinders (L7)
Firing on 8 Cylinders (L7)
Years of Membership: chevymaher has been a member for 10 full yearschevymaher has been a member for 10 full yearschevymaher has been a member for 10 full yearschevymaher has been a member for 10 full yearschevymaher has been a member for 10 full yearschevymaher has been a member for 10 full yearschevymaher has been a member for 10 full yearschevymaher has been a member for 10 full yearschevymaher has been a member for 10 full yearschevymaher has been a member for 10 full years
Posts: 14239
Topics: 90
Images: 94
Joined: November 2010
Gender: Male
Alias (AKA): chevymaher
Van Model Year: 1994
Van Make/Model: GMC Safari
Extra Info: SLE RWD Mercruiser

Re: Trying to understand tcc lockup and how the overdrive wo

Postby dvil » December 23rd 2012, 10:25pm

The TCC unlock is (also) controlled by the TPS. My '89 700R4 is doing the same.
Here's a hack-discussion from downunder: http://www.delcohacking.net/forums/viewtopic.php?f=28&t=735
1989 5,7L V8 TPI project
1989 parts/project
1989 LT. sold
1992 shorty AWD
1993 AWD (graveyard
1995 AWD (graveyard)
2004 AWD LPG, back in service with new heads
dvil
Fueling (1/2 tank)
Fueling (1/2 tank)
Years of Membership: dvil has been a member for 12 full yearsdvil has been a member for 12 full yearsdvil has been a member for 12 full yearsdvil has been a member for 12 full yearsdvil has been a member for 12 full yearsdvil has been a member for 12 full yearsdvil has been a member for 12 full yearsdvil has been a member for 12 full yearsdvil has been a member for 12 full yearsdvil has been a member for 12 full yearsdvil has been a member for 12 full yearsdvil has been a member for 12 full years
Posts: 50
Topics: 2
Joined: June 2008
Location: Norway
Gender: Male
Alias (AKA):

Re: Trying to understand tcc lockup and how the overdrive wo

Postby redfury » December 24th 2012, 12:30am

All TCC is doing is locking the hydraulic flow to the torque converter so that the fluid pressure builds up and locks that pressure so that it doesn't have the normal slip a non TCC transmission has. It's an extra step to increase gas mileage. My van shifts like it has 5 speeds with the TCC. Once in 4th it drops almost 500 rpm when the TCC engages at highway speeds. The transmission can be tuned to shift how you like it by someone with the capability if you have a newer van.
A temporary fix usually becomes a permanent solution, therefore it does not exist.
doghouse removal by me!http://www.youtube.com/watch?v=uIJ0kuROlbU
User avatar
redfury
U.S. Armed Forces
U.S. Armed Forces
Firing on 8 Cylinders (L3)
Firing on 8 Cylinders (L3)
Years of Membership: redfury has been a member for 10 full yearsredfury has been a member for 10 full yearsredfury has been a member for 10 full yearsredfury has been a member for 10 full yearsredfury has been a member for 10 full yearsredfury has been a member for 10 full yearsredfury has been a member for 10 full yearsredfury has been a member for 10 full yearsredfury has been a member for 10 full yearsredfury has been a member for 10 full years
Posts: 2958
Topics: 53
Images: 13
Joined: December 2010
Location: isanti, mn
Gender: Male
Alias (AKA): Mike
Van Model Year: 1998
Van Make/Model: Chevrolet Astro
Extra Info: LT 5.7L 4wd

Re: Trying to understand tcc lockup and how the overdrive wo

Postby Matrixx » December 26th 2012, 10:18am

Hi Bread Van

Everything you have mentioned is normal behavior on every aspect.

The TCC will come out of lock up briefly when it's in the locked phase (45 mph+) when you let up on the accelerator pedal, then apply it again (that's normal).

My suggestion here when loaded and climbing steep hills like that and not to stress the transmission so much, is to Select (3). This will take it out of overdrive and lock the TCC at the same time which gives you "crisp" shifts going uphill.

When shifting into 3, just make sure you are under 40 mph when you do it. It makes things a lot easier on the transmission. I have had to to it a couple of times myself with my van and that's what the owners manual says you should do anyways when the van is loaded/towing and/or going up steep hills, a lot less stress on the transmission doing it that way.

Just my 2 bits for what it's worth.:)
96-GMC Safari - Rwd - Original Transmission - Exhaust - Air Cared - 3.73 Limited Slip Rear End - Motor Replaced - 91 octane (Chevron) for the last 14 years - MFI Upgrade - 640,000 Kilometers.
User avatar
Matrixx
AstroSafari Pioneer
AstroSafari Pioneer
Firing on 6 Cylinders (L3)
Firing on 6 Cylinders (L3)
Years of Membership: Matrixx has been a member for 13 full yearsMatrixx has been a member for 13 full yearsMatrixx has been a member for 13 full yearsMatrixx has been a member for 13 full yearsMatrixx has been a member for 13 full yearsMatrixx has been a member for 13 full yearsMatrixx has been a member for 13 full yearsMatrixx has been a member for 13 full yearsMatrixx has been a member for 13 full yearsMatrixx has been a member for 13 full yearsMatrixx has been a member for 13 full yearsMatrixx has been a member for 13 full yearsMatrixx has been a member for 13 full years
Posts: 2640
Topics: 14
Joined: January 2008
Alias (AKA):

Re: Trying to understand tcc lockup and how the overdrive wo

Postby Shad0wXCalibur » December 26th 2012, 11:30pm

I have a giant transmission cooler. I can't even get the thing to warm up in winter :lol:
1987 Astro
2000 Safari
Shad0wXCalibur
Firing on 2 Cylinders (L2)
Firing on 2 Cylinders (L2)
Years of Membership: Shad0wXCalibur has been a member for 9 full yearsShad0wXCalibur has been a member for 9 full yearsShad0wXCalibur has been a member for 9 full yearsShad0wXCalibur has been a member for 9 full yearsShad0wXCalibur has been a member for 9 full yearsShad0wXCalibur has been a member for 9 full yearsShad0wXCalibur has been a member for 9 full yearsShad0wXCalibur has been a member for 9 full yearsShad0wXCalibur has been a member for 9 full years
Posts: 1225
Topics: 41
Joined: July 2011
Gender: Male
Alias (AKA):
Van Make/Model: GMC Safari
Extra Info: Lifted 2wd

Re: Trying to understand tcc lockup and how the overdrive wo

Postby Matrixx » December 27th 2012, 10:08am

Running a cold transmission can hurt it as well.

My point above was to stop the transmission from 'hunting" all the time and creating a lot more heat and wear on it. When (3) is selected, that's it, it's in 3.

If it needs to downshift even more, then it will go crisply into (2) and then back into (3) when your finished running the grade.

:)
96-GMC Safari - Rwd - Original Transmission - Exhaust - Air Cared - 3.73 Limited Slip Rear End - Motor Replaced - 91 octane (Chevron) for the last 14 years - MFI Upgrade - 640,000 Kilometers.
User avatar
Matrixx
AstroSafari Pioneer
AstroSafari Pioneer
Firing on 6 Cylinders (L3)
Firing on 6 Cylinders (L3)
Years of Membership: Matrixx has been a member for 13 full yearsMatrixx has been a member for 13 full yearsMatrixx has been a member for 13 full yearsMatrixx has been a member for 13 full yearsMatrixx has been a member for 13 full yearsMatrixx has been a member for 13 full yearsMatrixx has been a member for 13 full yearsMatrixx has been a member for 13 full yearsMatrixx has been a member for 13 full yearsMatrixx has been a member for 13 full yearsMatrixx has been a member for 13 full yearsMatrixx has been a member for 13 full yearsMatrixx has been a member for 13 full years
Posts: 2640
Topics: 14
Joined: January 2008
Alias (AKA):

Re: Trying to understand tcc lockup and how the overdrive wo

Postby Shad0wXCalibur » December 27th 2012, 10:50am

Well I'm trying to think of a more elaborate way to block off the grille for winter over a piece of carboard. The cooler is overkill currently but towing something in summer, that thing gets hot to the touch.
1987 Astro
2000 Safari
Shad0wXCalibur
Firing on 2 Cylinders (L2)
Firing on 2 Cylinders (L2)
Years of Membership: Shad0wXCalibur has been a member for 9 full yearsShad0wXCalibur has been a member for 9 full yearsShad0wXCalibur has been a member for 9 full yearsShad0wXCalibur has been a member for 9 full yearsShad0wXCalibur has been a member for 9 full yearsShad0wXCalibur has been a member for 9 full yearsShad0wXCalibur has been a member for 9 full yearsShad0wXCalibur has been a member for 9 full yearsShad0wXCalibur has been a member for 9 full years
Posts: 1225
Topics: 41
Joined: July 2011
Gender: Male
Alias (AKA):
Van Make/Model: GMC Safari
Extra Info: Lifted 2wd

Re: Trying to understand tcc lockup and how the overdrive wo

Postby Bread Van [OP] » January 14th 2013, 6:21pm

Thanks for the input guys. I'm definitely understanding auto transmissions better now. I have another car with an auto trans that seems to ride the torque converter a lot more and this information has helped me understand how I want to "tune" that transmission controller when the time comes. Now that I pay attention I'm generally pleased with the way the van shifts, it's just those rolling hills we have here in the Intermountain West (which are BIG to be called hills but smaller than an extended mountain pass climb) that give it fits.
Original Poster [OP]
User avatar
Bread Van
250k+ Miles
250k+ Miles
Firing on 5 Cylinders (L1)
Firing on 5 Cylinders (L1)
Years of Membership: Bread Van has been a member for 10 full yearsBread Van has been a member for 10 full yearsBread Van has been a member for 10 full yearsBread Van has been a member for 10 full yearsBread Van has been a member for 10 full yearsBread Van has been a member for 10 full yearsBread Van has been a member for 10 full yearsBread Van has been a member for 10 full yearsBread Van has been a member for 10 full yearsBread Van has been a member for 10 full years
Posts: 514
Topics: 36
Images: 0
Joined: March 2010
Alias (AKA): mapper
Van Model Year: 2003
Van Make/Model: Chevrolet Astro
Extra Info: AWD 2 inch lift

Re: Trying to understand tcc lockup and how the overdrive wo

Postby redfury » January 14th 2013, 9:06pm

It used to confuse me as to what "sport" mode on some automatic cars I drove in was. All sport mode does is increase the pressure threshold for each shift. In turn, the shifts become sharp and precise. In addition, there is decreased friction from allowing the TC to slip for softer shifts, it creates less heat and if left in sport mode, the transmission has theoretically less wear an tear. Same thing happens in OD trying to run up and down hills. The transmission hunts because it determines that OD isn't going to cut it so it drops into 3rd, but wants OD, so it'll push it into OD as soon as the pressures are right..rinse and repeat. Putting the tranny into 3rd allows for full lock up and you can drive your van at highway speeds in 3rd, you will just end up running your RPM up around 2500-3000rpm depending on your axle gearing.
A temporary fix usually becomes a permanent solution, therefore it does not exist.
doghouse removal by me!http://www.youtube.com/watch?v=uIJ0kuROlbU
User avatar
redfury
U.S. Armed Forces
U.S. Armed Forces
Firing on 8 Cylinders (L3)
Firing on 8 Cylinders (L3)
Years of Membership: redfury has been a member for 10 full yearsredfury has been a member for 10 full yearsredfury has been a member for 10 full yearsredfury has been a member for 10 full yearsredfury has been a member for 10 full yearsredfury has been a member for 10 full yearsredfury has been a member for 10 full yearsredfury has been a member for 10 full yearsredfury has been a member for 10 full yearsredfury has been a member for 10 full years
Posts: 2958
Topics: 53
Images: 13
Joined: December 2010
Location: isanti, mn
Gender: Male
Alias (AKA): Mike
Van Model Year: 1998
Van Make/Model: Chevrolet Astro
Extra Info: LT 5.7L 4wd


 
  • Related topics
    Replies
    Views
    Last post

Return to Automatic

It is currently March 1st 2021, 1:21am

Automatic Forum
AutomaticThe purpose of an Automatic Transmission is similar to that of a manual transmission, the auto tranny's primary duty is to allow the engine to operate in its narrow range of speeds while providing a wide range of output speeds.
To create a new topic in Automatic, click this button:
Previous topic Next topic
Recent Image Attachments
Attached by:
AngryPunk
in Automatic
Views: 240
Comments: 15
Date: Feb 18 '21
Time: 11:47pm
» Read last comment
Attached by:
Youngblood
in Automatic
Views: 137
Comments: 3
Date: Jan 15 '21
Time: 1:24am
» Read last comment
Attached by:
allenstoltzfus
in Automatic
Views: 310
Comments: 11
Date: Jan 14 '21
Time: 7:36pm
» Read last comment
Attached by:
runawayjim
in Automatic
Views: 206
Comments: 5
Date: Jan 07 '21
Time: 2:09pm
» Read last comment
Attached by:
Attached by: SportsBoy
SportsBoy
in Automatic
Views: 2885
Comments: 16
Date: Jan 05 '21
Time: 11:16pm
» Read last comment
Sponsors

Who is online

Users browsing this forum: No registered users and 12 guests