Truck wants to take off in gear

[CFoye]

This started on Saturday. Some history.



2005 Cummins, stock except for Smarty JR on #3. Towing a 4k lb boat, got it pretty hard, 3/4 throttle to get ahead of somebody, everything was fine until I came to a stop. Something started rattling under the hood and the truck wanted to take off. Pulled over put the truck in park and had the wife sit in the truck in gear and found that the transmission dip stick was vibrating against the firewall, fixed that but, the truck wants to take off. If I take it out of gear when I'm stopped, the RPMs surge up to 1500-1600 and then come back down. If I'm coasting and take it out of gear it doesn't rev up. If in park and I gun it it'll rev up to close to 3000 and takes a long time to come back down even after letting off the throttle.



Thought I'd take the Smarty out of the picture so, I put the truck back down to stock and it's still occurring.



Also checked for codes, none were listed.



Did a search but, can't seem to find anything to point me in the right direction.



Can anybody point me in the right direction?



Thanks

 

[cerberusiam]

If it wants to pull thru the brakes when stopped, is doggy on acceleration and the engine does not want to rev right away, and it runs and shifts fine when your up to speed, quite likely the TC has gone bad.

 

[Gasmasher]

I agree with cerberusiam sounds like your torque converter clutch has locked up on you

 

[CFoye]

This that a solenoid or a TC replacement?

Chris

 

[cerberusiam]

This that a solenoid or a TC replacement?



Chris

Likely its the TC itself that has gone bad, there is a sprag clutch that will go bad in it and cause the symptoms. The other possible problem is the pump is bad and allowing pressure to leak into the lockup clutch system and partially apply it. Not as common but it does happen so the pump needs to be checked also.

 

[macdaddy]

My 99 with the ATS trans would do this but less extreme. That turned out to be an issue with the Valve Body. When ur saying the truck wants to "Take Off" is the trans in neutral?. If so thats what mine was doing.



Theres no oil circulating through the valve body when in park.



Mac

 

[Bloomy]

Same thing on my friends 05 a few years ago. Full TQ replacement by dealer under warranty. Almost as if the TC wasn't unlocking.



Thomas