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S10 shift problems

jdezur

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jdezur New Member

jdezur

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A little background before the problems: Truck is a '99 s10 2.2l auto. Been great until about 60k miles, and currently has 71k. This is also the first major problem that I've had. (besides the u-joints going, but that was an easy fix--took it in.) :bs:

 

I have a feeling that this might be something expensive to fix, and would rather see if this was something I would be able to take care of.

 

The problem: While driving at 70mph, the tach usually has said 2500 rpm (for the first 60k miles). On our last vacation(last summer), we were driving up & down hills, the truck was having issues shifting. The SES light came on, pulled over, turned off, light went away. Continued on, and did it again. Same remedy again, but light has not came on since, but the problem is still there. We continued driving, and the truck seemed like it was getting stuck in 3rd, and not shifting to 4th. When it finally did decide to shift into 4th, it couldn't figure out if it wanted drive or overdrive. Needless to say, when it didn't want to shift, gas mileage went from 30mpg to the pits. It's been doing this on and off for about a year, but only on highway driving, and when it's warm. Since it's been cold, no problems.

 

Had a trip this weekend, and the problems resurfaced. Time to get it fixed.

 

Also, after this last long trip, when finally getting back to civilization and out of the farm fields, the tranny was having issues shifting from 1st into 2nd off stop lights. It would get to the proper speed, shift and literally throw you into the seat. If I had more power, the tires would easily have squeaked. It's never done this before, and I feel it's an indication that something may be going wrong. Duh.

 

Time for the annual filter change, and if something is wrong, I'd like to fix it while it's open. I'm thinking of installing a shift kit, since it would replace the parts that I feel might have gone bad. However, if it's something like a $2 part that crapped out, I don't feel like spending $100 to fix the $2 problem, and the problem is still there after the upgrade. Call me cheap, or smart, it's up to you.

 

 

The tach has been oh-so-wonderful during all this:

 

All driving done on normal flat ground, no hills (except overpasses)

 

Proper operation: 70mph 2500 rpms(4th gear, normal!)

Unusual operation (I go to pass, then go back to 70): 70mph, 2900-3100 rpms (stuck in OD)

Real unusual operation: 60-70 mph, 4000 rpms (this would be 3rd gear)

 

I can replicate the "unusual problem" almost every time. The "real unusual" I usually get when it tries to shift between 4th OD and 4th when I finish accelerating from passing. It acts like it wants to downshift from OD to drive (4th gear), but it revs to 4000 rpms(3rd gear), then shifts into 4th drive 2-3 seconds later, and will act normally until I need to pass(shift into OD) again, or slow down (thus downshifting).

 

I'm not a transmission guy, but am mechanically inclined enough to put stuff together. But, trying to replicate this problem to a service guy without literally driving the service guy around town for an hour isn't an option. If the truck sits and cools off (15-20 minutes) it goes back to normal, has no issues until it gets heated back up. (10+ miles of highway driving).

 

Ideas that I've had:

TCC (theres a TSB about this being bad, but it only affects 1-2 gear or half of my problem). But, not being a trans man, what is a TCC?

See this thread for explanation. This is what I'm trying to avoid. No rebuilds available in my wallet.

 

Valve body is shot. Don't have a clue on part #s or what's involved in getting one. I've seen references to get one off ebay and I'm not into getting car parts off ebay. I'm guessing that a shift kit has a new one of "these".

 

I tried to be thorough with the descriptions of the problems, but I'd like to try everything possible before "just rebuild it". With only 71k on it, why'd it crap out? I'm beginning to want to ditch this truck. :troll:

 

If it's like this for every gm tranny (which I'm getting the idea of from this newsgroup), gm may not be getting my business on my next vehicle(wife's ride is beginning to have issues, but it's under warranty!)

Cool Zr2 Enthusiast

Cool Zr2

Posted
Posted

TCC is the torque converter clutch.

 

the high rpm in 4th gear probably means your TCC isn't locking, but your 3rd to 4th gear is what throws a wrench into the diagnosis.

jdezur New Member

jdezur

Posted
  • Author
Posted

How about if it isn't shifting into 3rd, but rather "neutral", and the accelerator is at the same spot as if it was WOT on 3rd? Thought of this also...

 

If it's slipping (now that I know what the TCC is :troll: ) it could be slipping out of OD and into 4th, but it takes forEVER for it to grab. That I would think could be causing it too...

Cool Zr2 Enthusiast

Cool Zr2

Posted
Posted
How about if it isn't shifting into 3rd, but rather "neutral", and the accelerator is at the same spot as if it was WOT on 3rd? Thought of this also...

 

If it's slipping (now that I know what the TCC is :troll: ) it could be slipping out of OD and into 4th, but it takes forEVER for it to grab. That I would think could be causing it too...

Take it in and have a dealer look at it, you could have damaged the 3/4 clutch packs or bands somehow

jdezur New Member

jdezur

Posted
  • Author
Posted

Took it in, and dealer (well, trans place) said just rebuild it. Ugh... not exactly what I wanted to hear. :troll: Apparently they did an s10 with very similar problems a few weeks ago (dunno if it was just bs, or truth), and they've fixed the 1-2 clutch pack problem frequently and knew exactly what was wrong. The dropping to neutral/3rd from 4th thing they thought was kinda odd, but to fix the 1-2 problem, a rebuild was in order. This would then fix the 3-4-4OD problem also. So, the old s-10 is gonna be sold... I use this truck everyday for work, and can't afford for it to crap out in the middle. It's been a great truck!

 

Thanks CoolZR2 for the quick responses. If I end up with another p/u or s10 blazer/jimmy, I know i'll be back. This place is a great resource!

Jeremy WI Enthusiast

Jeremy WI

Posted
Posted

I think a P1870 correction kit might be worth an attempt. It involves boring out a passage in the valve body for an oversized apply valve. After the PCM sees the tranny slip so much while in OD(fourth gear) with the TCC locked it will command max line pressure(harsh shifts) and usually it will inhibit TCC lockup- so in fourth gear you'll probably run about 200 rpms higher

  • 5 years later...
korbin502 Enthusiast

korbin502

Posted
Posted
I think a P1870 correction kit might be worth an attempt. It involves boring out a passage in the valve body for an oversized apply valve. After the PCM sees the tranny slip so much while in OD(fourth gear) with the TCC locked it will command max line pressure(harsh shifts) and usually it will inhibit TCC lockup- so in fourth gear you'll probably run about 200 rpms higher

 

 

What is the P1870 correction kit?

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