I'm beginning to experience more problems with my auto tranny (R407W). If i am coasting then hit the gas, the RPM's pick up for 1.5-3 seconds before the trans engages. It does this in D and OD. It also shifts entirely too much. I did not recalibrate my speedo with my 265/75/R16 BFG's. Could this be what damaged my trans because it took it out of the powerband and the electronics make it shift at all the wrong times?

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97 F-150 4.6 4x4
K&N Fipk
Dual Flowmaster 50
Superchip
32" BFG's
Toyota stuck to bumper

 

Sounds like the torque converter unlocking and locking to me.

Hobbit

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99 XLT,4.6L Auto,4X4,tow pkge,Factory Side Steps and Mudflaps, K&N filter,BugflectorII, Amazon Green/Silver, Pace Edwards Rolltop Cover.

 

My 98 4x4 5.4L Expy with stock tires and Superchip is begining to act the same way at 56K. Letting off the accelerator when travelling at a constant speed on a flat road causes this same surge in RPM. Very disconcerting. .

It seems like lots of folks have reported this behavior, uncomfortably accepted this as "normal" TC lock/unlock behavior and later had trannys replaced...

 

My 99 4x4 5.4 does it too. I took it to the dealer and they said it was the torque converter locking and unlocking and this is a normal thing. I think they are full of **** but there is nothing I can do untill it gets worse. I have 19000 miles now but the dealer has a record of my problem so I hope it is covered via the warranty if it craps out after the warranty expires.