1993 4l80e

[jimalove]

Problem just started.First start up put transmission in reverse,won't move,rev engine 2 or 3 times to go in gear.What kind of problems can I look for?

1993 6.5TD C3500,96000 miles,towing 11,000 5th wheel.


Thanks

Jim

[john8662]

From everything I've read about 4L80E's is that when you lose reverse, it's mechanical in nature and requires disassembly of the tranmission. The 4L80E inherited the same poor design reverse gear that the TH400's had.

Any codes? Just curious!

[Robyn]

This is a common issue with a high mile tranny. The seals get hard and untill they warm up the oil will bypass them and not apply the band/clutch depending which way you are asking it to go.
It needs to come out and apart. A rebuild is the only real solution to the trouble.
You can try a small amount of a product called trans x it will soften the seals some and may give you a few more miles but it's not a magic cure all.
I have used it but the thing to remember is that it just keeps on softening the seals untill they are mush. Run it for a few days then completely flush out the box with clean oil and install a new filter. You might get lucky and have a fix that will get you a few thousand more miles.

Robyn