HI i just bought a truck and the owner said it is stuck in 4x4 low. it wont go over 40 mph and the rpms are almost pegged at redline while driving. They have replaced the transmission and transfer case with no change to the problem.
there is also a check engine light on but i cant get the codes to flash when i jump the E1 and T1 pins in the diagnostic box.

any help in getting this figured out would be greatly appreciated.
Now a little about the truck
1990 4x4 automatic with the v6 3.0
motor was rebuilt a year ago and has had about 10,000 miles put on it since then.

 

If jumpering E1 and TE1 (not T1) does not cause the CEL to flash, you have a bad ECU. Before I concluded that, I'd make sure I had the right pins.

On the transfer case, I'd suspect a linkage problem. But how someone could "replace" a transfer case and not catch that is beyond me; I would at least move the shift lever with my hand before installing it. Of course, I also can't figure out why someone would buy a truck with a stuck transfer case, despite not knowing anything about transfer cases. So I'm probably no help.

(If you have the A340H, the transfer case is more like an automatic transmission. It has a solenoid, and it throws codes. The codes could tell you a lot.)

 

ok i went out and found the te1 pin...dont know how i missed it before! I jumped the te1 and e1 pin but when i turn the key to the on position the check engine light flashes rapidly and doesnt stop...i ounted all the way up to 56 rapid flashes before i stopped counting. there was no pauses in between flashes.

and i bought the truck in the condition its in because I am confident its not a transfer case issue since its been replaced and still has the same issue. and i got it cheap.

 

When you get if figured out be sure to please let us know what you find.

Just what do you think is the cause ??

 

The automatic transmission/transfer case diagnostic codes don't show up on the CEL, they show up on the O/D Off indicator light. Here is a link to the FSM for the various automatic transmission versions. Pick the one you have and go to the troubleshooting and diagnosis sections and follow the procedures.
http://personal.utulsa.edu/~nathan-b...autotrans.html

 

I tried to pull the codes off of the overdrive light but, just like the check engine light, it just flashes rapidly over and over with no pauses in between flashes

 

Do you have proof that they replaced the tranny/t case? what happens when you try and shift it out of low range?

Heres a good thread on the a340H

http://www.pirate4x4.com/forum/toyot...sues-faqs.html

 

Well the old transmission and transfer case are sitting in the bed of the truck. its pretty covered in oil and crap and the one on the truck is a lot cleaner so I'm assuming the replacement is on the truck.

 

Well the old transmission and transfer case are sitting in the bed of the truck. its pretty covered in oil and crap and the one on the truck is a lot cleaner so I'm assuming the replacement is on the truck.

 

Check all your wires to the xfer case. I suspect you can trick this thing into 2hi with a B+ wire so you drive it, until you figure it out. It may just be a bad ECU.

 

A few other people have mentioned the ecu as a possible culprit. Its possible I guess. I did notice that where the "kickdown"? Cable goes into the tranny is loose. The metal or plastic collar just pulls out of the hole and slides up and down the cable a little bit. Could this be the issue

 

Did you just buy this out of Victorville?

 

Yes I did actually... Where you looking at it as well? Or do you know some of the history of the truck

 

I was looking to get it, seemed like a pretty good deal. If you get fed up with it let me know, I got more patience than many.

 

Ill let you know, but this is my dream truck so ill work on this thing until i figure it out haha

 

how would i trick it into 2hi?

 

But yes, if the E1 to T1 jumper just flashes constantly it's probably a bad ECU. The trans and engine are controlled by the same ECU which may be causing the problems. I'm not sure if it could over-ride the trans shifter, that's new to me. Open up the computer and look for leaky capacitors. I've had one leak and eat through some traces before.

 

Not sure how to trick it but the switch wiring is probably close to this:
http://www.snjschmidt.com/wiring/trans1.jpg
http://www.snjschmidt.com/wiring/trans2.jpg

Maybe check to see if L4 is grounded out on the ECU.

 

I swapped out the ecu and still had the same problem. On my test drive I don't think it is actually stuck in 4 wheel drive. If I shift into 2h the 4x4 indicator light goes out. Starting to seem more like its not shifting out of second gear. When I take off it kinda struggles to go then shifts kinda hard then gets moving but never seems to shift after that? There is a little bit of play on the gear shifter in the truck so maybe I should be looking into adjusting the shift linkage?

 

From what you are saying the ECU was bad, now we are finding the other problems. If it will not go into 3rd it may very well be a linkage problem, or a TV cable from the engine.