I found a 1996 k2500 that I am thinking about. It is right at 100k miles and wondering how the thing will hold up and it will be my first diesel so I am not sure what to expect. I was curious if some years of transmissions were better than others. I have read about the different blocks and some being more prone to cracking than others and was wondering if there was similar information about the transmissions as well. Thanks

The 96 4L80 had a grounding issue that would cause premature failure in some units, but I would think at that age and milage you should be alright. I've got 172,000 on my 95 now with no signs of trouble, and many others have high milage on there 4L80's as well. In my opinion the 4L80 is a good trans after about 92 or 93 when they got the initial bugs worked out.

I have a friend with 320k on his 93 4l80E and no significant problems.

4l80 history-91 introduced--91-93 had the most problems-epc solenoid could stick letting line pressure go to 800 psi often breaking third gear drum or shattering piston,accumulator housing wasn't best design either,94-95 had new internal and external (better) harness with re-designed epc prssure solenoid,96 they went to a high energy(better friction co-effiecent) clutch pack material to match the new vortec motors,97 they changed from cast aluminum clutch pistons to stamped steel/molded rubber (better),deep factory pan,redesigned the pump body,changed from conventional internal sealing rings to vespel style,piped oil lube return from cooler directly into center support in side of trans,added some oiling grooves to sun gear and planetarys,oil circuit changed as to oil flow to planetary gears (solid shaft,old one oil traveled down the center),some bushings had oil grooves added to them,99-some bearings were added were there used to be thrust washers, some had planetarys with 5 gears instead 4,02-all of them got 5 gear planets,overdrive panet and roller clutch were redesigned. I hope this helped educate a few guys,some of these mods added strength but it doesn't mean the old ones were weak or junk either,Smitty

i got 153,000 km's , less than 100,000 miles before mine went. 3600.00 rebuilt.