2004 transmission question ....

[TKarnas]

I have a 2004 with Auto and about 62000 miles on it. Since I bought the truck about 2 years ago with 52000 miles the truck will seem to shift at about 50 miles per hour going down hill with little or no gas. I know I am in overdrive as I can count the shifts. So can this truck free wheel? When I step on the gas again transmission does not slip.



I have had work done to it, Shift kit, gov solenoid replaced.



Any help is appreciated.

 

[cerberusiam]

OD has an over running clutch so they all freewheel in OD. Not sure what you mean by "shift" though.



Are you feeling another shift after you get into OD?



Offhand its the TC locking but not sure from your description.

 

[TKarnas]

Well I ment to say... . The truck will hit overdrive about 45mph, then while going down hill about 50 or so ill feel the truck buck. If it was a manual I would think it poped out of gear. The truck picks up speed. Does not do this under load pulling hills or straits. Just going down hill, enough of a bump that you feel it. I guess yes it feels like its going into another gear.

 

[jelag]

On the 04 trucks when the throttle pedal is at rest, the transmission reduces the pressure in the Torque Converter and it is freewheeling. It stays that way until you add fuel again, than the ECM on the engine and the computer for the transmission decide what it needs to be doing, and it sets the correct gear and adds pressure to the torque converter to lock it up... .

When and exhaust brake is added to the trucks built before 06 a kit is added to the transmission to hold the pressure in the torque converter up, the ECM holds the pressure up until the truck slows to about 1100 rpm than its released.

So when you release the throttle no matter what gear the transmission is in... it just free wheels...

 

[cerberusiam]

Well I ment to say... . The truck will hit overdrive about 45mph, then while going down hill about 50 or so ill feel the truck buck. If it was a manual I would think it poped out of gear. The truck picks up speed. Does not do this under load pulling hills or straits. Just going down hill, enough of a bump that you feel it. I guess yes it feels like its going into another gear.

Must be the TC unlocking from low TV pressure, then it feels like it free wheels because it is in fluid coupling.



Must be the nature of the pre-05 trucks and the minimal controls, mine won't unlock the TC until it hits 35 mph in a coast condition.

 

[Jeepr]

Not sure if it's what you are feeling, but if mine is in tow/haul mode, and I'm not on the gas and maybe lightly braking downhill, it will downshift. I assume to assist with the braking.

 

[TKarnas]

Thanks everyone ! sounds like everything is "normal" from what I read. I was affraid transmission was going up...