Rishi
Well-Known Member
My son rebuilt his first A727 transmission last week. I've done 5-6 of these over the last decade or so. He's watched and assisted on the last few. He wanted to do this one for his own car by himself, and although I was salivating to help, I backed away and gave him the freedom, tools and service books to run with it. He went with a full B&M Trans Kit and the Hemi 5.0 kick down lever.
He's test driving it and it has an issue. He's gonna drop it today, and bring it over, this week, for my help. I'd like to get in front of the problem and have some idea where to look.
When cold, it shifts just fine and all appears functioning. The throttle pressure linkage was adjusted prior to service. It seems to upshift and downshift correctly.
However, when warmed up and/or hot, it falls back from third to second gear. It does so in varying throttle positions, freeway or back road. Letting it cool for 8-10 hours, it runs fine again. But when hot, again slips out of third. He called me after his third day of this happening. When coming to a stop, it starts out fine in 1st, then 2nd, but won't go in to 3rd. Downshifts fine from 3rd to 2nd (when cool/cold) and 2nd to 1st (all conditions)
I suspect he nicked the front clutch pack seal on assembly. Normally, I would just rebuilt the whole transmission, and replace all the seals and rings, since we are tearing it down, anyway. But I'm concerned he may feel that "he didn't do anything right, and he didn't do any of it good enough."
I don't believe I'm seeing this precise issue in the FSM troubleshooting section. I'm going to sit down and go through it again before he comes next week
So I'm looking for some second opinions to help me focus on where to look. I've been lucky and never needed to test line pressures in my rebuilds, but that was one thought I had.
He's test driving it and it has an issue. He's gonna drop it today, and bring it over, this week, for my help. I'd like to get in front of the problem and have some idea where to look.
When cold, it shifts just fine and all appears functioning. The throttle pressure linkage was adjusted prior to service. It seems to upshift and downshift correctly.
However, when warmed up and/or hot, it falls back from third to second gear. It does so in varying throttle positions, freeway or back road. Letting it cool for 8-10 hours, it runs fine again. But when hot, again slips out of third. He called me after his third day of this happening. When coming to a stop, it starts out fine in 1st, then 2nd, but won't go in to 3rd. Downshifts fine from 3rd to 2nd (when cool/cold) and 2nd to 1st (all conditions)
I suspect he nicked the front clutch pack seal on assembly. Normally, I would just rebuilt the whole transmission, and replace all the seals and rings, since we are tearing it down, anyway. But I'm concerned he may feel that "he didn't do anything right, and he didn't do any of it good enough."
I don't believe I'm seeing this precise issue in the FSM troubleshooting section. I'm going to sit down and go through it again before he comes next week
So I'm looking for some second opinions to help me focus on where to look. I've been lucky and never needed to test line pressures in my rebuilds, but that was one thought I had.
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