Truck info:

1991 Toyota 4Runner SR5
4x4
3.0 V6
Automatic
Stock bumper to bumper (except rims)
195,XXX miles

Background:

Acquired this truck from my sister after she couldn't get it to go more than about 10 mph up the hill from her apartment and it threw a CEL. Once in my possession I had to add about 1.5 qts to the engine. When I turned the truck on there was no longer a CEL and the engine sounded perfect. After taking it around the block everything seemed fine. Next day I attempt a longer drive just to have the CEL come on about 8 miles into it. As soon as the CEL came on the truck went into limp mode and the transmission started shifting hard. Shut off the truck and checked the fluids - all showed proper levels. When I turned the truck back on to limp it home the CEL was off and the truck shifted like normal for about half a mile and the CEL came back and the truck started to limp again with almost no power (okay, even less than normal) and hard shifts. Once I got it home I saw transmission fluid had coated the underside of the truck and seemed to be coming from the front of the transmission. I haven't been able to track down exactly where from yet though. And again no CEL on start up so I can't check for codes. Any ideas on what has happened? Any pointers or thoughts would be much appreciated.

Cliff notes of problem:

Truck throws a CEL that causes it to go into limp mode with less power and hard shifts. Once the truck is turned off the CEL goes away and the truck functions like it should until it is driven a half mile or so and the CEL will come back. Transmission fluid appears to be leaking a lot suddenly from somewhere near the front of the transmission when the truck was limped about 8 miles home.

 

Features of the A340H transmission:
Electronically controlled shifting. When the computer detects a mechanical or speed sensor problem, it goes into a "limp home" or failsafe mode. It will defaut into 3rd gear (direct drive) and the OD light will flash.

 

You pull codes on the motor by jumping the T1 E terminals in the diagnostic port on the PS of your engine compartment. Use a paper clip and jump those terminals. Turn the key to ON and the CEL will blink a code. Count each code and reference them.

For the tranny, you can start trouble shooting here:
http://www.toyotaholics.com/support/...sp?TOPIC_ID=19

 

Thank you for the link - Extremely informative.


The problem is the code only throws the CEL once it has been driven and does not come back on right away after the truck has been turned off. So turning the truck to the "on" position doesn't ever show the CEL.



After going outside and messing with a bit tonight I think the transmission had too much fluid in it thus the fluid leaking. I can intentionally get the CEL to trip by putting the truck in gear (any gear) and accelerating for about 20 seconds with my foot on the brake. I believe its when the transmission is trying to shift. According to the Pirate4x4 link posted above it sounds like it may be the shift solenoids. Does this sound right to anyone else? They are really expensive to replace without them being the problem. Anything else I should check out first? Thanks for all the help so far.

 

Also, I have not had the A/T Temp light come on at all or the OD light flash at all if the helps narrow things down.

 

The CEL does not have to be on for a code to be stored. If the CEL was on, even just a quick flash, you probably have a stored code. Follow the previous instructions and see if you have a stored code.

 

Didn't know that, I'll give it a shot. Thanks.