Why will my 98 Jimmy not shift into 3rd, or 4th gear? It is an automatic 4L60E transmission. It all started on a trip to Gatlinburg, TN. It felt like it was slipping when shifting into 3rd, intermittently for several months before finally failing completey to shift into these gears. What is going on here?
There are lots of things that could be going on there. You’ve got the electronic controls, the fluid, and the mechanical aspects to worry about. Take it to your best local transmission-specialty shop. Chances are you’ll need a rebuild.
Presumably you have at least checked the transmission fluid.
Thats the 3-4 clutch assy which is gone. This is a very common problem as the 3-4 stackup is a weak link in these transmissions. Nothing you can do here short of a rebuild.