TCC solenoid on an A4LD.

[mjnavatta]

Aloha all,

This is my first post on this forum...thanks in advance for all your suggestions and advice.

So here's what I'm dealing with....
I have a 1991 Ford Explorer with a pushrod 4.0 V6 and an AL4D transmission. X99,000 miles. I bought it with X20,000 miles (I ASSUME X=1, but not sure). The tranny is 4-speed, but living on the side of a volcano is WAY hilly. I don't use it, hence, in the following explanation I limit myself to 3rd gear, as I do in my local driving. I know virtually nothing about trannies as I've been fortunate that I've never had problems with any. I do the maintenance on them is all...and I do all the engine work myself, down to pistons and rings. I'm hoping, with some help, I can tackle this myself.

my Explorer started to giving me problems where the tranny does not like to downshift by itself...I must manually shift down the column when needed. If I stop, while in D, the tranny will, with a soft clunk, shift down to 2nd from 3rd...it will never go to 1st, to do that, I must manually shift to 1. While accelerating, if one starts with the shifter at 1, and begin to accelerate from a stop, then shift directly to D, the tranny will shift normally and comfortably to 3rd gear.

I ran the engine codes the other day and got 629, Torque Converter Clutch Solenoid circuit failure. It seems pretty consistent with what I've been reading on the net. What do you think? If that is it, has anyone done the replacement? My Haynes is completely devoid of any mention of my TCC solenoid, except, the code information...

 

[BrooklynBay]

Welcome to this forum! I've moved your thread into the transmission section. The sticky thread called the A4LD valve body rebuild diary on the top of this section explains how to replace the TCC solenoid. First check the internal wiring harness & solenoid with a multimeter before you remove the valve body. Adjust the kickdown cable too.

 

[MrShorty]

KOEO/CM 629 would be triggered by an electrical fault (open or short to ground) in the TCC solenoid circuit. I would expect the TCC circuit to only effect whether or not the TCC locks up or not -- I wouldn't expect it to have any effect on the 3-2 or 2-1 downshifts. I would expect something else in the valve body/governer/modulator is causing it not to downshift.