One of my cars has a stock, unrebuilt 4L60E with about 135k miles on it. The OD went out a couple months ago, and today when I put the car into park, it made a really weird sound...almost like leaves rustling, but much louder of course. It only does it in park, and seems to pull ok in all gears, except OD of course. I'm looking for a good used 4L60E (don't want ot put much $$$ in this car, I'm selling it soon) to put in it now, but how long do you think this trans is going to hold out? Any ideas what is wrong with it? I mainly need to know if it should be safe to drive until I can get another transmission for it. Obviously this one is toast.

 

Lost OD? Is it just not shifting into 4th, or is it slipping? If it is slipping, that kinda worries me, because 4th gear has three components applied, and all three of those components are also used in other gears as well. All forward gears use the foward clutch, 2nd gear uses the band, and 3rd gear uses the 3-4 clutches. So if 4th is slipping, its amazing thats the only gear thats slipping, and I'm sure that another will soon follow.

 

The car is driveable in the OD position, but it only goes through the first three gears. It doesn't slip in any gear, it just won't go past third gear. To clarify a little, the rustling sound (which sometimes is a high pitched squeal) also occurs in reverse, but forward gears are not affected in any way. The car seems to drive normally, other than a new development that may be unrelated. Yesterday, when this noise first happened, the circuit breaker (30amp) on the power windows popped. When I left work last night, I pulled it out, reinserrted it, and it worked fine. Later last night, it blew again, and so did the wipers and radio (on the same circuit with the windows). The taillights got dim, and the turn signals didn't work at all. This car (94Z) does have a bad Opti, which I'm replacing next week (the car won't be driven til then), but I don't think this is related.

 

If the car has gears 1-3 but no longer has fourth gear, it sounds like you've got a problem in your valve body. Possibly a problem with oil travel to the 2-4 clutch band.

 

A seal may have been left out of the servo area.

 

The trans is untouched original...so I don't think anything could have been left out. I'll probably have the trans out early next week, so I'll know for sure.