Guys, I have a 88 3.0 auto. When I bought it a few months ago it had been sitting for 2+ years. I did the head gasket and a few other issues and now am tackling the tranny issue that has been there since I got the truck.
It shift fine in R and thru 1-2-3 but will not go into OD. I disconnected the computer under the console and test drove it shifting manually and OD did engage. So I assumed it was a solenoid issue. I replaced the solenoids (all of them) and I am still not getting OD.
I initially checked everything under the hood so I know it is not an issue there.

Could it be the ECT computer that is an issue? Do these things ever fail? Or is it time for a rebuild on the tranny?

Any advice you can give is greatly appreciated!

Mark

 

ADMIN, can you kick this fool out of here?

 

Check the temp sensor for the trans ecu to see if the wire is damaged or it has a bad sensor.I am not sure which one it is but it should be next to the engine temp sensor.
x2 on kicking the fool out.

 

OD also won't work if your fluid level isn't right on, it's really sensitive and can be tricky the way their hot/cold ranges are laid out. Check the manual for the exact temp range and use a thermometer if possible to make sure you're in it. Hot range seems to be more accurate. Might also try flushing and replacing with Valvoline Maxlife, good stuff.

 

jbyvt, fluid level is spot on. i wish it was that easy.
I was able to get OD to work when I disconnected the box under the console.

 

my problem was a sticking T-Stat. causing the engine to never reach operating temp. make sure your reaching operating temp

 

I don't think that is it, this issue of no OD was happening before and after I replaced water pump and t-stat. Engine operating temp seems not to be the issue.


Keep the ideas coming, I am all ears and my patience is wearing thin...

 

If you're sure of all this probably time to tear into it. Maybe try the diagnostic but I can't vouch for it personally. Guessing you have the A340H like I'm pretty sure I do on my '88? All the info you'll need from basic to rebuild at

http://www.pirate4x4.com/forum/showthread.php?t=587521

 

Did you change out the Solenoid in the T-case as well ? I know you said all of them but some people only mean the ones attached to the trans.

 

McKenna, I did not change that one. I bought a kit and replaced all that were in the kit (the ones in the tranny)
Could the solenoid in the t-case cause the problem I have described?

 

I believe the Solenoid in the T-Case is your OD solenoid, from what I remember.