Shifting weird into OD

[LJRuddy]

A friend of mine has a 98 SHO with 153,700 on the dial. Tranny has never been rebuilt and the car has been taken extremely well care of. Never raced, never sees 3k on acceleration. A few months ago, he let a friend drive it and he shifted the car from park to reverse when it was idleing around 2500 due to the bad IAB connection. He chirped the wheels and ever since then, the trany has had a minor shifting problem.

1st gear into 2nd shifts firm but smooth. Going from 2nd to 3rd is good and clean too. However, when the car is about to go into 4th, the T/C seems to lock up in 3rd so that the tach drops about 500 rpms. At this time, the tranny acts like it wants to shift into 4th but it 'changes its mind' at the last second and stays in third. Then, it will shift very harshly into 4th and continue on like nothing happened. All of this happens in less than 1.5 seconds. There is no O/D light on but the SES light is on due to another problem that has something to do with the intake. I am thinking that it is just time to get a tranny rebuild seeing that there is nearly 154k on the stock tranny with maybe 1 or 2 fluid flushes on it. Is there something that can be fixed or is it just time for new parts? The transmission works like new when it downshifting or upshifting except that one thing.

Any advice would be great!

 

[LJRuddy]

Bump... Anybody?

 

[nik97]

A possible cause of this is a faulty forward clutch shift valve retaining clip. This clip is flawed from the factory and has an TSB related to it. There is a "beefed" up factory replacement clip available as this was a warranty issue when the AX4N was was still covered. I have a 97 that had this issue and experienced similar symptoms before the clip gave out entirely. When the clip fails competely, there is no OD and the OD cancel light will blink(rationality monitor). This may not be what is happening but if you loose 4th, you will know.