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1997 GMC suburban 5.7 4wd ac 4L60E transmission. Shifts 1st & 2nd. then slips on 3rd. but if bring RPMs up it seems to hit 4rd. but not overdrive. Manually shift 1 - 2 then direct to OD at 45mph can do 55 mph at about 3600 RPMs. Changed both shift solenoids and still same, no oil burn, just brought truck home (185 miles) and other than burning alot of gas, truck ran fine in 3rd (??) gear. I do have a problem when the truck sits, the battery dies, new battery, same. Pulled every fuse and plug I could find with a meter in line with battery, still shows small drain. Could my computer be bad?? How would I check??Thanks
Optional Information: Year: 1997Make : GMCModel: SuburbanEngine: 5.7
The problem with the transmission is not electrical. If you totally unplug the electrical from the transmission, it will default to 3rd gear. Since your trans is slipping in 3rd gear the problem is mechanical within the transmission. Most likely a failed 3-4 clutch. This will require rebuilding or replacing the transmission.
Dave, Maybe I used the wrong word (slipping) rather it seems when it shifts out of 2nd. I can bring the RPM's up and the truck will keep going, no slipping, just seems it's not getting the correct signal. Still think clutch?
After the 2-3 shift, if you give it gas does the rpm go up without the vehicle accelerating?
I am not sure if it goes into 3rd but after it goes out of second looking for third i can bring the rpm's up and the trucks keeps moving. Thats how I drove 180 miles. It is not like I am in 2nd because the truck increases speed going down hills. 3600 rpms I could maintain 55 MPH. Before changing the solenoids, I drove and when it came out of 2nd. I put the shifter manually to second gear (2) and the truck went back to 2nd. Could I have changed the wrong solenoids? 2 front of valve body when pan removed. Are there more solenoids in the trany?
The shift solenoids face the rear of the vehicle with the pan removed.(#14 & 19 in the picture below)
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