I did a search but couldn't find what I was looking for so here goes....

1) When in Drive and at a complete stop, is the TC locked or unlocked?

2) On a Vac. Mod 4L60E, what controls the TC lock up?

TIA and happy holidays!

 

The tc is unlocked when your stopped.

 

1. When stopped (or pushing the brake pedal), the TC is unlocked.

2. TC lockup is controlled by the TCC lockup solenoid. The 46-MOD (for the 4L60E) replaces the pressure control solenoid (different from the lockup solenoid).

 

Thanks guys.....some more questions then. Supposing the TC were locked when stopped, what would the symptoms be or how would you know?

 

It would be overheating.

 

Your car would stall and die. Same as having a stick in gear at a stop light.

 

Thanks again for the replies. More questions in my quest for knowledge...

Does the TPS play a part in shifting? If so, what?

Does the VSS play a part in shifting? If so, what?

 

Thanks Spoolin.....what would happen if the truck were stopped and in second gear?

 

You can pick up an ATSG manual (with supplement) on ebay for dirt cheap. In that manual it goes through just about every conceivable scenario on troubleshooting. It also shows you how to do a basic rebuild... including recommended specialized tools.

Bill

 

1. TPS output tells PCM helps PCM determine what gear to engage based on forward speed and throttle position.

2. VSS provides the actual speed to help determine which gear to shift in.


Take Bill's advice on acquiring an ATSG manual, or PM me. Maybe we could work something out. Not that anyone doesn't want to answer questions, but the manual is actually a great learning tool for basic transmission operations & troubleshooting. You can get e-copies of those online for ~$35+ each.