4l60e Transmission Issue....

Solomon_Man · March 21, 2011

All,

I purchase a 1993 Silverado 1500 with a 350 and 4 speed 4L60E auto transmission. When I bought it, the previously owner told me that he was using the vehicle regularly until one day the transmission stopped shifting all together. Meaning no forward or reverse in any gear selection. The vehicle sat about 3 months before I purchased it.

I purchased the vehicle for a fair price knowing of the issue with the idea to work on it come spring. Well I have begun working on the transmission and I found the manual valve (inside the transmission), which is connected to the gear selection mechanism (internal and external) completely disconnected and basically hanging from the valve body extremely extended. It appeared like it slipped out or was internally forced out. The pan had not been open, at least not recently and the fluid was clean with no foul smell.

I slid it back in and reattached the manual valve to the external selector mechanism and put everything back together with new fluid, filter, etc and all seemed well. Forward and reverse seemed to be there but I noticed that the park\Reverse location on the cab gear shifter/selector seemed to be a little off compared to the read out (P,R,N,D,D,2,1). Anyways that did not bother me much as I have had more then a few vehicles where I had to feel where each "gear" is at. I drove the vehicle around my drive and yard, never making anything higher then maybe 1st or R... but any gear I was now in I moved.

I parked the vehicle in the hopes to do a standard tune up and detail it out come a warm day as I did not know the maintenance history. The warm day came and I moved the vehicle to a place where I can do some work. Upon entering the vehicle in park, I was about to turn off the engine when I notice the vehicle seemed to be engaged in a gear. Like... I had my foot on the break but was lightly hitting the gas pedal. I gave the vehicle a little gas (1 second tops) and I felt a slight movement of the vehicle until it let up entirely and it was like the vehicle was in neutral/park as it should have been. I then put the vehicle in any gear and it appeared that only forward was working in some of the gears. Currently (a day later) the vehicle has no gears (forward/reverse) again.

So my first guess is all these transmission issues, previous to my ownership, and now these new issues are all related to the manual valve not fully disengaging the transmission due to the manual valve adjustment/External linkage. I still have to pull the pan to see what happened exactly this time but my guess is the valve is out again from fluid build up in the valve body. My second idea, without a ATSG manual, is maybe a solenoid is shot and allowing this to occur by some unfortunate fluid build up situation.

Does any of these assumptions seem reasonable?

Has anyone seen this kind of behavior before?

How do I adjust this out or do I need to replace some parts. If so, any suggestions on where to look?

With the cross member and pan arrangement on this vehicle, this is not something I want to do a to many times....If I can help it.