727 Shudder in Reverse, then rattle on 1-2 shift

JWB said
I'm back! I crawled underneath and adjusted the kickdown. It is a 4.2 lever, so I used 72 inch pounds and backed it off two and one quarter turns. No change. The awful sound on a firm 1-2 shift is still there. There is no sound on the 2-3 shift, even on hard acceleration. I also tried a manual 1-2 shift (held it in low then manually upshifted to second) and the rattle/clunk is still there. It is an awful sound. At this point, I am beginning to wonder if the rear planetary is giving up on me? Based on an operation manual on this transmission, it seems to be the most likely culprit since it is not engaged at all in 2 or 3. I still have reverse, but it does still shudder/shake ever so slightly in reverse. Thoughts?

Anything is possible. The front planetary takes more of the abuse than the rear planetary but doesn’t mean the rear can’t fail. Why it shudders in reverse? Hard to say, possibly a sealing ring on the front pump stator or lip seal in the front clutch piston. But if that were the case, similar issue in 3rd would occur. So I’m not entirely sure, just going through stuff to try and help it make sense.

With an automatic shift valve body, lots of things can get happen. I would triple check your kickdown linkage and throttle valve adjustment. If they are spot on, it may be time to pull this trans out and go through it. Especially with the possibility of a hard part starting to fail. If it were mine, I’d be pulling it out.

RJ