Truck stuck in 4x4 low
#1
Truck stuck in 4x4 low
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.
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.
#2
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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.)
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.)
Last edited by scope103; 02-24-2015 at 05:15 PM.
#3
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.
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.
#5
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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
http://personal.utulsa.edu/~nathan-b...autotrans.html
#7
Registered User
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
Heres a good thread on the a340H
http://www.pirate4x4.com/forum/toyot...sues-faqs.html
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#8
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.
#9
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.
#11
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
#16
#17
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.
#18
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.
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.
#19
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?
#20
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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?