TC not locking all the time

[Robrt32]

I had posted about this in the 91-94 section but thought maybe more tranny guys may read here.................... From what Ive read and been told my problem sounds like solenoid trouble..Its locks up sometimes, It could go a week and work perfectly then go a week and never lock once.. My question , I need to know how a transmission illiterate person could check it? I'm pretty fair mechanic but never been inside a tranny before{ boy that don't sound right..} What do you think would be reasonable price for a shop to charge?.. we have very few trans shops around here.

 

[MrShorty]

The first thing I'd do doesn't require getting into the tranny at all. How are you with electrical? The TCC solenoid circuit is a pretty basic DC circuit. A quick check of the circuit my reveal a loose connection some where. If you put a voltmeter across the solenoid, you would be able to see if the computer is commanding the shift or not, and if the transmission responds when the command is given. The output state test (see my notes on pulling EEC-IV codes) can be useful for seeing how it looks when the computer changes the solenoid state.

 

[Robrt32]

I'm not good at all. Ive read those threads and don't get it.. I will check and clean the connections soon as the weather permits. I drove a 80 mile round trip this morning, going it never locked on the way back it locked perfect every time..Another question are the solenoids the same in a 91 as a 94? I have a whole 91 parts truck that the trans works fine in.

 

[Jack Flash]

Hi from a fellow Mississippian. Ethel, MS to be exact.

Sounds like you either have a solenoid problem or sticky valves in the valve body.

Here's a link to a valve body overhaul (long but will give you an idea what you're up against)

http://www.explorerforum.com/forums/showthread.php?t=137972

,
,

J...happy wrench turning.

 

[Turdle]

I wonder if the issue could be as simple as a bad throttle position sensor?

 

[Robrt32]

I wonder if the issue could be as simple as a bad throttle position sensor?

How would I go about checking that?.. Do they have to be set? or just bolt on?

 

[MrShorty]

If the TPS were part of the problem, it would affect the PCM commanding the shift, which would come back to my original suggestion to see if the PCM is commanding the shift or not.

TPS is a basic potentiometer. Testing it should be pretty easy with a voltmeter/ohmmeter and a wiring diagram. Make sure the TPS is seeing Vref (+5V) and that the voltage/resistance changes smoothly throughout the throttle range.

 

[Robrt32]

I noticed yesterday when it doesn't lock up, If I press on the gas a little harder , say 65-70 mph without it locked. I do get a check engine light.. Soon as I slow back to 55 it goes out.. I can run 85 when it IS locked and don't get the light.. The only thing to do is , read that thread some more and try to figure out pulling the codes.. I wish there was a "pictures for dummies" on the procedure.. I figured out how to pull the codes on my Toyota with a picture thread from Yotatech.. I haven't been able to find one here as of yet..

 

[MrShorty]

I didn't post any pictures in my thread because there are pictures all over the net. If my set of instructions isn't clear enough, try the set in BrroklynBay's EEC-IV code list thread (also in the EEC-IV forum, and I know he has a schematic for how to setup to pull codes). I also like the set of instructions at www.troublecodes.net/Ford The set at fordfuelinjection.com is also fairly well written, if a little verbose (and it seems that they don't explain the KOER test). If none of those are to your liking, put "Ford EEC-IV self-test" into your favorite search engine and you'll find plenty of hits.