Tc Lockup???

[Brock]

I hear you guys talking about making your TC lockup and having problems on highway in 4th with it locking up or coming out.



What are you talking about... I know it is the torgue converter but I have never had a vehicle where I could tell it was not working nor have I ever tried to cause it to lock up earlier than normal like some talk when racing and stuff.



Please enlighten the unenlightened on here... . I feel like a 14 year old in his first engine shop class.....

 

[obie1]

Thank you I too also wonder what they are talking about. I don't know if mine is locked up or not.



How do you know and what should you be looking for?



Used to have a 2003 3500 CTD and 6 speed, now I have a 2006 MC auto CTD. (BTW this machine is SWEEEET :-laf )

 

[cerberusiam]

Watch your tach when you acclerate under rmoderate to heavy throttle. When the TC locks you will see about a 300 rpm drop. It almost feels like another shift because of the loose converter. When the trans shifts to OD it locks the TC almost immediately so it is hard to tell the lockup is there. Its a lot easier to feel when your are under a load as there is a bit of a delay.



Unless there is a problem with the trans, the lockup scheme is pretty good on the 05's and 06's. It doesn't jump in and out of lockup in 4th unless you are working the throttle pretty hard and under a pretty good load. The older trucks with the 47RE were a lot worse as every time you moved the throttle up or down the TC unlocked.



The biggest complaint is not the TC lock but the tendency for the trans to bounce between drive and OD when you have a heavy load. Certain speeds are hard to maintain becuase of the ECU protecting the trans so you get a lot of shifting instead of holding a gear and lockup.



FYI, if you want to feel the TC lock scheme find yourself a moderate hill and manually shift your way from 1st to drive and hold the throttle about 3/4 depressed. You should have 2nd lockup, drive lockup, and OD lockup that feel like another shift point part way thru the gear.

 

[WCPoe]

Normal lockup mph

My normal driving lockup usually happened about 47-50 mph, both with the stock trans and the same with my ATS trans if I let the factory computer control it and not my ATS Commander which I added with the ATS transmission upgrade.

 

[jcroman]

Thank you I too also wonder what they are talking about. I don't know if mine is locked up or not.



How do you know and what should you be looking for?



Used to have a 2003 3500 CTD and 6 speed, now I have a 2006 MC auto CTD. (BTW this machine is SWEEEET :-laf )

You know your in lockup if the spedometer and the tach both move at the same speed. if you hit the gas and the tach doesnt jump way up then its locked..... oh and you will certainly feel more power too!!!!

 

[obie1]

Thanks for the information. You guys are a tremendous help. I am really impressed with the lack of sarcasm.



Have a great and safe weekend Oo.