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Discussion Starter · #1 ·
I had a minor collision in my92 Rodeo, and now that we've put the truck back together, the automatic transmission isn't shifting right. I think I have the 4L30E tranny.

What's happening is 1st and 2nd stay engaged for much longer than they should. 2nd doesn't kick in until almost 30mph is reached, and 3rd at about 50mph!(~4500 rpm for each of these). I'm not sure it's even making 4th gear at highway speeds. Secondly, when I slow down to 42-45, the transmission will downshift too early, causing the engine speed to shoot up to around 3500 rpm, (then I either have to haul brakes to slow the engine down, or sipped up so that it will shift back to a higher gear.

This morning (cold and wet), the behavior changed a little bit. Now the transmission won't shift back down into first (I have to shift it with the gear shift ). I think it knows it's supposed to downshift, because the "Check Trans" light comes on.

It doesn't seem like there is a mechanical problem with the transmission. When it shifts, it shifts fine, and does not slip. It's just not shifting at the correct speeds. It seems like it's just not getting the right signals.

The collision was left front, and was pretty much just bodywork. There wasn't any damage to the any of the mechanical systems.

Here's what we changed. There was damage to the wiring, harness, and a lot of the wires had to be repaired. But I'm pretty confident in my solder joint and shrink wrap repair job. We also had to move around some of the computer parts in the interior to get to the fender bolts, but nothing had to be disconnected. I still need to open that back up and make sure everything is dry and connected properly.

While everything was apart, we also changed the timing chain and gears. I don't know if that would cause any difficulties.

I just wanted to post this in hopes that someone may have some suggestions on things I could check out to address the issue, or may have some ideas on where the problem might lie.
 

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Discussion Starter · #3 ·
Thanks Ryan,

I'm look after that tonight or tomorrow morning to see if I can find one.

I don't look forward to going back into that wiring harness though.

My Haynes manual has a wiring diagram which shows which colors go to the TCM. Any idea how reliable that could be? These manuals often seem to be wrong for my cars. :(
 

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Yep, you've got a 4L30-E. Check out this website -- page 4 tells you how to diagnose some basic problems. One of the recommendations is disconecting the TCM and driving around shifting through the gears manually. That'll help you figure out if it is the TCM or your wiring job or if there is something deeper going on here. You should also be able to scan codes from the computer to see if it's trying to tell you anything.

The website is: http://www.transtec.com/rebuilder_news/2nd_q95r-n.pdf

The transmission thing might also be coincidence and have nothing to do with the accident -- you never know, maybe it was it's time!
 

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Discussion Starter · #5 ·
Thanks,

Saw that article mentioned in another posting. Good stuff. My transmission seems to have put itself into "safety" mode, so i's pretty much staying in 3rd, and I just shift manually. That seems to be working out just fine, so at least I am pretty confident that the innards of the transmission are working properly.

I've been looking for vacuum leaks and bad wiring, but everything seems OK. Looks like I'll need to get a code reader on it.
 
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