At least I think it is. I rebuilt the transmission about a year and a half ago. First time ever.

Well, the trans works fine now when its cool, but yesterday it would not shift firmly into 3rd at WOT. It would hit the shift point at 5,000rpm as normal and then slowly wind down to the shift recovery point.

When cruising it acts like the TC is unlocked, and I can't determine weather it is, or isn't. In 4th gear I'll roll onto the pedal and the rpms will slowly rise, matching the speed of the car and it will accelorate. But then the rpm's will hit a brick wall and the revs will stop climbing even though the car is still slowly accelorating. its like it is hitting its stall point.

During all of this, the rpm's are all within normal ranges for the speed and gear.

What might this be? I don't have the money to pay someone for a rebuild so I will probably end up doing it myself.

Suggestions anyone?

 

No one has any ideas?

 

I know absolutely jack about tranny's. I'll admit it right now, in case I sound like a complete numbnut, but....

Vacuum modulator, maybe? Or the vacuum line running to it?

 

I'm having a tough time understanding the symptoms, except for the mushy 3rd gear shift.

Stuck servo comes to mind for that particular complaint, assuming the clutch pack is in good shape.

 

Transmission is working perfectly again. No delay on the 2-3 upshift.

It gets mushy when it gets hot. I need a transcooler. I had the pan down and the fluid was good. Nor was there any friction material in the pan. I had a very light smearing of it on the magnet, but it wasn't anything i'd worry about.

The problem could be the servo, I guess I'll have to take it out and replace the seals.

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The transmission is essentially a stock rebuild with a Transgo Shift-kit, Vette servo, .500" boost valve and .250" low/reverse boost valve.

 

Just check the servo for movement against the spring pressure, push it in and verify it moves in/out.

One of my old junkyard TH700R4 trannies had a stuck servo and had mushy 2-3 shifts. No telling how long it had been sitting.

Same indicators as what you report, very little material in the pan and otherwise fine behavior except for mushy 2-3 shifting that got mushier as the trans got hotter.

The servo assembly was a bear to get out of the casing, but we finally wiggled it free and got a replacement TCI or whatever piece installed.

 

This is exactly what mine is doing right now. Did you find the problem?

 

not to hijack or anything.. but how firm should a 700R4 that is OEM Shift? should it be a pretty firm shift? like enough to squeak the rear tires in 1-2 shift without trying very hard?

 

TTT