Strange, one time shudder after very long uphill drive.

Strange, one time shudder after very long uphill drive.

Postby gman [OP] » June 25th 2020, 9:09am

Hello all.
I just took my astro/safari on a long uphill drive while trying to find a good spot to overlook a city and hang out.
By uphill, I mean a consistent 11-20% gradient for about 2-3 hours.
Much more of a gradient than the mountain roads that it has seen lately.
It performed perfectly fine, no muss no fuss, and it shifted fine throughout the whole ordeal.
I considered dropping it to 1st and just driving it like that, but the massive amount of engine braking that would occur kind of shied me away from it.
I'd much rather wear on my brakes than my drivetrain.
There were enough downhill/not so steep areas to just leave it in D.

When I was done with that drive, at one stoplight, I noticed a slight shudder that happened at idle, then kind of continued until it rolled through about 20-ish ft.
It was a very hard shake that felt transmission related rather than engine related.
Almost like it was about to run out of gas or had a massive vacuum leak or something (or evren close to the crank position sensor error that I felt on the 05), but it didn't sound like the engine was suffering, just like it was struggling to move and stay alive, which seemed kind of related to the transmission, but maybe that's just in my head?

It immediately went away, and then never came back.
I did have a slightly shakier idle after I let the van cool, but nothing too crazy, just a different kind of slight vibration that I have felt in the past that occasionally comes and goes.

I didn't notice any difference in shift points, and no difference in drivability.

I also checked my transmission fluid immediately afterwards, and there was no sign of burning or anything.
Levels were exactly at the cross hatch, and it smelled like normal transmission fluid.

It hasn't happened since.

Also, the other day I coasted in neutral and would occasioanlly throw it in D while it was rolling.
I didn't step on the gas immediately, and allowed the vehicle to kind of "meet with" the drivetrain before I gave it gas, and I gave it to it slow until it slowly felt normal and then sorta gave it throttle to push through the mountain areas.

Some notes:
I did put a bottle of techron in the other day because I had it and I wanted to clean out my injectors I just bought, and right after doing that, I noticed that it was kind of weird that my throttle response felt immediate.
I was in deadlocked traffic on an uphill though, so I'm not sure if the van compensates for that. It kind of seemed to normal out when it got level, but my throttle response was still a little more immediate than it had been in the past.

I did do the P1870 fix that changes the TCC lockup from the spring loaded thingy to just on/off.
Before then, I would get P1870 after a highway drive and got the hard 1-2 shift.
It hasn't thrown a transmission code since.

I put a corvette servo in it, without a long pin.
That doesn't seem to be much of an issue as there was barely enough room for the servo itself as it is.

I checked with my scanner just to be sure, and there were no pending codes, and it had already completed a drive cycle.

It was kind of a small thing that just happened really quick, didn't cause any fuss afterewards, and went away.

I still haven't put in my new plugs/cap/wires/rotor yet. Kind of wondering if I should.
I know for sure that the current plugs are fouled from the old injectors, and I kind of want to replace all of it before it becomes an issue, but at this point I'm considering just doing the plugs.

My queston is:
Do you guys think that all of these things are transmission related?
If the transmission is working hard, like when going on a huge gradient like that for so long, are those typical symptoms of a really hot transmission?

Maybet it's not related to the transmission at all?

if the vehicle had been driven with the blown out TCC valve for a while, that would wear on the torque converter rather than the transmission right?

Anyways, any insight would be appreciated.
I'm not super concerned yet, as the problem was so quick, codeless, and has compeltely gone away.
But should I be?
1999 Chevy Astro Van
Original Poster [OP]
gman
Firing on 2 Cylinders (L1)
Firing on 2 Cylinders (L1)
Posts: 281
Topics: 31
Images: 29
Joined: February 2020
Alias (AKA):
Van Model Year: 1999
Van Make/Model: Chevrolet Astro
Extra Info: Base 4.3 RWD

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Re: Strange, one time shudder after very long uphill drive.

Postby sixsix » June 25th 2020, 4:16pm

gman wrote:Hello all.
I just took my astro/safari on a long uphill drive while trying to find a good spot to overlook a city and hang out.
By uphill, I mean a consistent 11-20% gradient for about 2-3 hours.
Much more of a gradient than the mountain roads that it has seen lately.
It performed perfectly fine, no muss no fuss, and it shifted fine throughout the whole ordeal.
I considered dropping it to 1st and just driving it like that, but the massive amount of engine braking that would occur kind of shied me away from it.
I'd much rather wear on my brakes than my drivetrain.
There were enough downhill/not so steep areas to just leave it in D.

When I was done with that drive, at one stoplight, I noticed a slight shudder that happened at idle, then kind of continued until it rolled through about 20-ish ft.
It was a very hard shake that felt transmission related rather than engine related.
Almost like it was about to run out of gas or had a massive vacuum leak or something (or evren close to the crank position sensor error that I felt on the 05), but it didn't sound like the engine was suffering, just like it was struggling to move and stay alive, which seemed kind of related to the transmission, but maybe that's just in my head?

It immediately went away, and then never came back.
I did have a slightly shakier idle after I let the van cool, but nothing too crazy, just a different kind of slight vibration that I have felt in the past that occasionally comes and goes.

I didn't notice any difference in shift points, and no difference in drivability.

I also checked my transmission fluid immediately afterwards, and there was no sign of burning or anything.
Levels were exactly at the cross hatch, and it smelled like normal transmission fluid.

It hasn't happened since.

Also, the other day I coasted in neutral and would occasioanlly throw it in D while it was rolling.
I didn't step on the gas immediately, and allowed the vehicle to kind of "meet with" the drivetrain before I gave it gas, and I gave it to it slow until it slowly felt normal and then sorta gave it throttle to push through the mountain areas.

Some notes:
I did put a bottle of techron in the other day because I had it and I wanted to clean out my injectors I just bought, and right after doing that, I noticed that it was kind of weird that my throttle response felt immediate.
I was in deadlocked traffic on an uphill though, so I'm not sure if the van compensates for that. It kind of seemed to normal out when it got level, but my throttle response was still a little more immediate than it had been in the past.

I did do the P1870 fix that changes the TCC lockup from the spring loaded thingy to just on/off.
Before then, I would get P1870 after a highway drive and got the hard 1-2 shift.
It hasn't thrown a transmission code since.

I put a corvette servo in it, without a long pin.
That doesn't seem to be much of an issue as there was barely enough room for the servo itself as it is.

I checked with my scanner just to be sure, and there were no pending codes, and it had already completed a drive cycle.

It was kind of a small thing that just happened really quick, didn't cause any fuss afterewards, and went away.

I still haven't put in my new plugs/cap/wires/rotor yet. Kind of wondering if I should.
I know for sure that the current plugs are fouled from the old injectors, and I kind of want to replace all of it before it becomes an issue, but at this point I'm considering just doing the plugs.

My queston is:
Do you guys think that all of these things are transmission related?
If the transmission is working hard, like when going on a huge gradient like that for so long, are those typical symptoms of a really hot transmission?

Maybet it's not related to the transmission at all?

if the vehicle had been driven with the blown out TCC valve for a while, that would wear on the torque converter rather than the transmission right?

Anyways, any insight would be appreciated.
I'm not super concerned yet, as the problem was so quick, codeless, and has compeltely gone away.
But should I be?

Maybe.
Well, after all... what would Banacek say ?... “I'd like to get The Team - Face, BA, Howlin' and the Spousal Unit back together, go out West, buy Brandon's / CFM's Van and drive it down the West Coast - see our beloved Big Trees and AS.com Members.”


.
User avatar
sixsix
Orange Status (L5)
Orange Status (L5)
Years of Membership: sixsix has been a member for 6 full yearssixsix has been a member for 6 full yearssixsix has been a member for 6 full yearssixsix has been a member for 6 full yearssixsix has been a member for 6 full yearssixsix has been a member for 6 full years
Posts: 4092
Topics: 36
Images: 1214
Joined: May 2014
Location: Edgewood, Northern Ky.
Gender: Male
Alias (AKA): Mike
Van Model Year: 1992
Van Make/Model: Chevrolet Astro
Extra Info: LT W CPI - RWD 200K

Re: Strange, one time shudder after very long uphill drive.

Postby sixsix » June 25th 2020, 4:17pm

gman wrote:Hello all.
I just took my astro/safari on a long uphill drive while trying to find a good spot to overlook a city and hang out.
By uphill, I mean a consistent 11-20% gradient for about 2-3 hours.
Much more of a gradient than the mountain roads that it has seen lately.
It performed perfectly fine, no muss no fuss, and it shifted fine throughout the whole ordeal.
I considered dropping it to 1st and just driving it like that, but the massive amount of engine braking that would occur kind of shied me away from it.
I'd much rather wear on my brakes than my drivetrain.
There were enough downhill/not so steep areas to just leave it in D.

When I was done with that drive, at one stoplight, I noticed a slight shudder that happened at idle, then kind of continued until it rolled through about 20-ish ft.
It was a very hard shake that felt transmission related rather than engine related.
Almost like it was about to run out of gas or had a massive vacuum leak or something (or evren close to the crank position sensor error that I felt on the 05), but it didn't sound like the engine was suffering, just like it was struggling to move and stay alive, which seemed kind of related to the transmission, but maybe that's just in my head?

It immediately went away, and then never came back.
I did have a slightly shakier idle after I let the van cool, but nothing too crazy, just a different kind of slight vibration that I have felt in the past that occasionally comes and goes.

I didn't notice any difference in shift points, and no difference in drivability.

I also checked my transmission fluid immediately afterwards, and there was no sign of burning or anything.
Levels were exactly at the cross hatch, and it smelled like normal transmission fluid.

It hasn't happened since.

Also, the other day I coasted in neutral and would occasioanlly throw it in D while it was rolling.
I didn't step on the gas immediately, and allowed the vehicle to kind of "meet with" the drivetrain before I gave it gas, and I gave it to it slow until it slowly felt normal and then sorta gave it throttle to push through the mountain areas.

Some notes:
I did put a bottle of techron in the other day because I had it and I wanted to clean out my injectors I just bought, and right after doing that, I noticed that it was kind of weird that my throttle response felt immediate.
I was in deadlocked traffic on an uphill though, so I'm not sure if the van compensates for that. It kind of seemed to normal out when it got level, but my throttle response was still a little more immediate than it had been in the past.

I did do the P1870 fix that changes the TCC lockup from the spring loaded thingy to just on/off.
Before then, I would get P1870 after a highway drive and got the hard 1-2 shift.
It hasn't thrown a transmission code since.

I put a corvette servo in it, without a long pin.
That doesn't seem to be much of an issue as there was barely enough room for the servo itself as it is.

I checked with my scanner just to be sure, and there were no pending codes, and it had already completed a drive cycle.

It was kind of a small thing that just happened really quick, didn't cause any fuss afterewards, and went away.

I still haven't put in my new plugs/cap/wires/rotor yet. Kind of wondering if I should.
I know for sure that the current plugs are fouled from the old injectors, and I kind of want to replace all of it before it becomes an issue, but at this point I'm considering just doing the plugs.

My queston is:
Do you guys think that all of these things are transmission related?
If the transmission is working hard, like when going on a huge gradient like that for so long, are those typical symptoms of a really hot transmission?

Maybet it's not related to the transmission at all?

if the vehicle had been driven with the blown out TCC valve for a while, that would wear on the torque converter rather than the transmission right?

Anyways, any insight would be appreciated.
I'm not super concerned yet, as the problem was so quick, codeless, and has compeltely gone away.
But should I be?


Wow! Maybe.
Well, after all... what would Banacek say ?... “I'd like to get The Team - Face, BA, Howlin' and the Spousal Unit back together, go out West, buy Brandon's / CFM's Van and drive it down the West Coast - see our beloved Big Trees and AS.com Members.”


.
User avatar
sixsix
Orange Status (L5)
Orange Status (L5)
Years of Membership: sixsix has been a member for 6 full yearssixsix has been a member for 6 full yearssixsix has been a member for 6 full yearssixsix has been a member for 6 full yearssixsix has been a member for 6 full yearssixsix has been a member for 6 full years
Posts: 4092
Topics: 36
Images: 1214
Joined: May 2014
Location: Edgewood, Northern Ky.
Gender: Male
Alias (AKA): Mike
Van Model Year: 1992
Van Make/Model: Chevrolet Astro
Extra Info: LT W CPI - RWD 200K

Re: Strange, one time shudder after very long uphill drive.

Postby gman [OP] » June 27th 2020, 8:11pm

I don't think this was transmission related anymore.
I also had a weird issue the other day where my throttle was stuck and I was constantly accelerating.
I had to pull over and move the unclipped cruise cable out of the way and lube the spring.
1999 Chevy Astro Van
Original Poster [OP]
gman
Firing on 2 Cylinders (L1)
Firing on 2 Cylinders (L1)
Posts: 281
Topics: 31
Images: 29
Joined: February 2020
Alias (AKA):
Van Model Year: 1999
Van Make/Model: Chevrolet Astro
Extra Info: Base 4.3 RWD


 
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