Need advice from transmission expert-1992 Lesabre

[spinne1]

Hello. I need some opinions on the cause of a tranny fault. I bought a 92 LeSabre cheap because of a bad tranny. The tranny will not move in drive. It will just rev up. If you chose "1" on the gear selector you can drive the car forward SLOWLY until you get to about 15 miles per hour and then you can shift it to "2" and it will shift and you can slowly accelerate to 25 or 30 and shift to "D" or "O" and it will drive normal up to and including freeway speeds.

I took the tranny apart hoping to find something obvious. I found virtually every part in excellent condition. The only two things I am questioning are:

1. The bearing that wraps around the output shaft and goes inside the sun gear was loose and free when taking out the parts (but is it not free to move when not inside the sun gear and does it not come apart at one point in its circle?)

2. The sun gear had a little bit of wear/broken teeth right where the other metal piece sits around it, but only at the very bottom and only on part but not all of the teeth.

From doing some reading it appears it could be a seal issue. I also wonder whether it could be a solenoid or worn valve body or something else.

Any ideas?

PS The fluid is a brownish red but not too dark. I have found no significant metal debris. The forward band looks very good.

The tranny has 138,000 miles on it.

[HotZ28]

Did you inspect the input shaft/drum seal? The original seal is prone to deteriorate and cause internal leaks resulting in low line pressure. GM had a TSB about this particular seal and and the effects, along with a redesigned seal as a replacement.

[spinne1]

HotZ28: I will look into what you wrote. I'm not sure what exactly the "input shaft/drum seal" is however. I have the ATSG book and nothing is labeled as such and I don't have enough experience with rebuilding trannies to know the lingo. I do have access to all TSBs for this vehicle and I'll research to see what I can find about transmissions.

Thank you.

[trannyman52]

no solenoids are required for initial movement,,,though one is active for first gear,,,....the one-way roller sprag in bottom is possibly damaged,,,,will cause this problem,,,,teflon rings on input drum must be replaced,,,they do wear,,,,teeth missing,,,not a good thing,,,kinda tough to give good advice without seeing parts,,,am assuming this is a 4T60-E trans,,,not a 440-T4