High Sierra 2500
10-26-2005, 01:46 PM
I posted this in the 6.2 forum and someone over there suggested that I post it over here. To begin with, the truck is an '85 GMC C2500 with a 6.2 diesel and 120,000 miles. It seems to have some transmission adjustment problems. I believe the truck is equipped with a 700R4, but the options list in the truck says "heavy duty trans", so it may be a replacement transmission (but I doubt it). Anyway, when you place the shift selector in park, reverse, or neutral it goes right in gear and works fine. When you put it in overdrive it hesitates for a moment and then goes in gear. Not a big problem, but if you put it in any of the lower gears (by detent, not indicator) it doesn't go in gear at all. It just slips. I tried putting it in overdrive, going down the road and shifting to drive, but it acts almost like it is in neutral. Once again, it seems to work fine when the selector lever is in the any gear except for 1st, 2nd, or 3rd. It shifts fairly decent, and doesn't seem to make any noise. I checked the fluid, it is full and doesn't look or smell bad. Any thoughts on what to check here? Any adjustments I can do to fix this? I don't know to much about these automatic transmissions, so any help would be appreciated.