I don't know about the 3rd gens but 2 nd gens you tap the brake while keeping you foot on the gas if the vibration goes away its the TC on its way out.

Thanks for the info I will try that today!

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Well I tried to duplicate what sthrnrider was talking bout and I couldn't really tell any difference. I'm taking it in on Friday though and hoping we can get something figured out?!?!

Ok so I drove it this weekend and noticed that the vibration is only there when the truck shifts into OVERDRIVE? Once the truck is in overdrive, vibration will be steady until the granny shifts down. Peak vibration is 70mph anything before or after that is mild but it's there. :argh:


This is driving me crazy!!!!! Any help is always appreciated.

When it shifts down are you still at same speeds you notice the vibration at? What does it do when coasting down from 70? Is it vibrating just at cruise or under accel in o/d? Could be a prob in o/d unit or rear end, tires, tcase. Id try running in a diff gear at the same speeds you notice the vibration. to rule some things out. Really your tranny shop should be checking all this.

Yes to first question. When coasting down from 70 mph, I will get vibration. Also when coasting down from 70 the truck will keep a higher idle until it drops out of o/d. The vibration is most prominent at cruise and deceleration, upon acceleration I don't notice the vibration. Could be harmonics of the engine disguising the vibration? I'll try running a different gear and see?:humm:

Does anyone know a good tranny guy in Oklahoma? I'm truly at a loss:argh: