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Code 1870

31K views 38 replies 16 participants last post by  gman 
#1 ·
Well heck, my "Service Engine Soon" light came on today and I was sure it was a P0440 code since I only had half a fuel cap. I replaced the cap and checked the code and it turned out to be 1870 trans slipping.
Didn't expect this 'cause the trans feels fine but guess not LOL
I bought a case of trans fluid and a new filter and tomorrow after work I'll use our trans fluid exchanger to clean it out. Hopefully that will at least slow the slippage a bit. Guess we'll see.
I'm just finishing a C6 rebuild using some 4R100 parts so at least I'll have room on my home work bench for the next job!

Jon
 
#28 ·
chargedbird said:
Here's a stupid question:

Once the VB has been replaced, what adjustments or resetting is needed if any.

Thanks..
To my understanding you should have your battery disconected for about 1 day so the codes been erased from memory. This action Also resets the adaptative procedure strategy in all 97 up PCMs as a response to compensate for the wear the PCM commands to the PCS aka force motor and timming delays.
 
#29 ·
Hey everyone,
I thought I would add to this excellent thread, as it seems to be the definitive one for the torque converter clutch slip and code 1870 transmission issues.

Although my 1999 2WD van did not display the 1870 code, my van was shuddering/stuttering/hesitating when driving in Over Drive. Several other AstroSafari owners have this shudder and live with it, but I thought I would swap out the Valve Body with a rebuilt unit to eliminate any pressure issues with the PWM-TCC valve bore wear (an known issue on the 1998-1999 4L60E transmissions).

I purchased a rebuilt valve body from Ken Partin Transmissions for $105! it even came with a 1-2 shift ball repair kit and nice directions. Highly recommended.
http://www.kenpartintransmissionparts.com/4l60e-rebuilt-valve-b460.html


Now, as it turned out, changing the valve body did not improve the shudder in OD, so my van's torque converter clutches are probably worn (at 115kmiles), so I may add some friction modifier in the short term, but certainly a new torque converter in the long term to avoid the eventual failure mode.

Here are some supplemental pictures for doing the Valve Body change out with the transmission still in the van.
The many great YouTube videos do the valve body change with the transmission belly up on a work bench.
Here are the notable differences with doing the job "upside down."

The first issue is fluid drips... wear safety glasses, and allow for fluid to drip and drain.


The wire harness does need to be moved out of the way, but not removed. I zip tied it to the exhaust pipe.
Note: the lock-up solenoid is an integral part of the harness and you may want to put it in a plastic bag to keep dirt off of it.


The Switch Assembly does not have to be removed, only the three 10mm bolts need to be removed (keep the two 8mm bolts in the Switch Assembly)


Before removing the valve body, let the fluid drain for several minutes.... let it rain.
Note: when you do drop the valve body, the seven check balls may fall out.


The Valve Spacer Plate will stay in due to the Accumulator and the Retainer plate.


After the Spacer Plate is removed, this is where the Accumulator Spring, Filters, and #10 Check Ball go on the "case" side of the spacer plate. So you can see how it will be "reinstalled".


If you are going to make the 1-2 shift ball repair in the Valve Body Spacer Plate, then this is where you will find it.
The hole needs to be bored out with a 1/4 inch drill bit and the valve seat is then installed (with the seat pointing to the valve body side, not the case side).


Before you attempt to install the gaskets and valve body spacer plate, apply some fresh fluid to the surface to make the gasket "stick". The picture shows how the gasket fits snugly on the newly installed 1-2 check ball seat.


Before you install the valve body spacer plate and gaskets into the transmission, you will need to secure the number 10 check ball in place with some TransGel or Vasaline... it sits right next to the accumulator. Note: there are two other check balls in the case, but they are captive by some collars and you don't have to worry about.


Use two of the bolts to help align the far end of the gasket and spacer plate as you install the Accumulator and Retainer Plate finger tight (at the engine side of the transmission).


Before installing the valve body, figure out where all the bolts go. Here is a picture of how my bolts fit, and notice that the three bolts in the "upper left" of this photo have 8mm heads. Three long 10mm bolts go into the Switch Assembly. Most bolts are "medium" length 10mm bolts.


Diagram of bolt locations.


The last step is to install the wire harness, and the Lock-up Solenoid, and the PWM TCC solenoid.


Add about a gallon of fresh fluid and you are done.

Good luck,
Herminator
 
#31 ·
Update... Bought the valve body from Ken's and installed without any issues... However I also installed the 1-2 shift ball repair kit.
The good news is the P1870 code is long gone, and the trans shifts smooth, but what I now noticed is that when I gun it, the trans shifts hard from 1 to 2, but when normal driving it seems fine. I read a post in this forum 'somewhere' about the TPS causing this issue, but can't find it now.
Anyway, If anyone can chime in and let me know what I can check that would stop the 1-2 hard shifting I would appreciate it, cause I'm actually going to buy a new valve body spacer plate and gaskets and redo it to see if that's still the problem, because when I pulled my spacer plate the 1-2 shift ball was actually stuck in it, which is why I used the 1-2 repair kit.

Looking for a local parts store to get the plate and gaskets now... Anyone know a local parts store that sells them in/near Franklin Park, IL?

Thanks for the info!
 
#32 ·
Check your 1-2 accumulator spring, its a very common thing to break, just google 4L60E 1-2 accumulator spring. Basically theres a spring under that accumulator piston that softens the 1-2 shift which is the apply of the 2-4 band, when the spring breaks, the accumulator no longer gets its cushion during apply and in turn, it snaps that band down and you get a 1-2 shift RIGHT NOW instead of the old slushbox shift we're used to. Take note of the clearance between the piston and center pin and how the piston fits in its bore, if its sloppy get a kit there are lots out there so do your research before you pick one. Also note which side is facing which direction so you remember during re-assembly. Hopefully its just a spring. Let us know what you find, add pics if you can!
 
#33 ·
Hello All,
My wife and I recently bought a 98 Astro AWD with only a 108xxx miles on it. We bought it in the winter so we didn't experience any hard shifts until recently as the weather for hotter. Doing some reading revealed that the vavle body is worn out or wearing out. My question is this.... If I buy a remanufactured valve body will I eventually have the same problems? I'm experiencing the hard shifts from first into second and some times from second into third. I want to fix the problem not temporarily fix it only to arise again in a few years. Please advise. Thanks
 
#35 ·
I just fixed this with a fitzall teckpack and the video on their site.
https://www.fitzall.com/supportDetail.php?A74741Q-188

Did it on the side of the road in an industrial area with just jackstands to lift it up a few inches so that I could get under it.
Took about 3-4 hours because of the weird positioning.
Didn't have to remove the valve body or do anything crazy.
Get really thin needle nose pliers (no really, get the ones that are specifically advertised as very slim) and you should be fine.

One tip: Don't trip to squeeze the clip ends together, it will take forever. Instead, rotate the clip ends so that one is touching the wall of the groove that it is in, then putting one end of your pliers on the valve body and the other end on the outside of the clip end, squeeze really hard.
It should flatten the side hitting the wall.
Just repeat for the other side, and get your third hand ready while you spread the clip to release the valve.

I think that this is the cheapest and easiest way to fix it, as it solved my problem, cost about $8 (well, with a new pan and filter, and some tools it was closer to $40), and I was able to do it on the side of the road.
 
#36 ·
I do like that install video thinking a little bit outside the box but getting it done without dropping the VB.

I think the cheapest would be inserting a $0.50 spring from your local transmission shop that would do the exact same thing. They know which one it is.

It does do away with the PWM for the TCC and makes it on-off only, giving full line pressure to the TCC which will definitely be harder on certain parts and probably cost elsewhere like fuel economy. But if it gets you some more life out of the transmission before needing to be completely rebuilt then it's a freaking awesome cheap and easy fix. Sonnax has a lot of good info on it's site as well.

Good work!

Edit: adding to link your other thread here: https://www.astrosafari.com/viewtopic.php?f=70&t=141804
 
#37 ·
AstroWill said:
I do like that install video thinking a little bit outside the box but getting it done without dropping the VB.

I think the cheapest would be inserting a $0.50 spring from your local transmission shop that would do the exact same thing. They know which one it is.

It does do away with the PWM for the TCC and makes it on-off only, giving full line pressure to the TCC which will definitely be harder on certain parts and probably cost elsewhere like fuel economy. But if it gets you some more life out of the transmission before needing to be completely rebuilt then it's a freaking awesome cheap and easy fix. Sonnax has a lot of good info on it's site as well.

Good work!
I did notice extremely smooth 1-2 shifts, which probably means that the torque converter is working harder to shift through those gears, so I got a Corvette servo to get more positive and firmer lockup (just not as bad as it was lol).
It feels better when it's smoother, but I think that really smooth means more work for the TC. Correct me if I'm wrong.
 
#38 ·
I have a 2000 astro has a P1870 code. The code only comes up when it goes over 55 mph for final freeway speed then will shift hard once code come up. It was cleared and as long as I can stay under 55 mph no issues. Can anyone advise me on what needs to be done and cost to be fixed.
 
#39 ·
Bump to add material.
I did this fix, and I also added a corvette servo. Not for performance reasons, but because it would increase the line pressure, and I didn't like how long it stayed between first and second.
I heard that the delay in shifting, which is usually done for a more "pleasant" driving experience, could also put more wear on the torque converter, and I figured it was worn already from hunting between 3rd and 4th.

Fixing the P1870, provided it is ONLY the valve in the valve body wearing out, is relatively simple, but could be awkward and take a while as a first time job.
But you literally just need to drop the pan, finagle the clip open to push the other valve out (hardest part), put the other valve in, and replace the clip.

I used this video:
 
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