This concerns my brother's 97 GMC Yukon. Today he was going to class, riding about 30-40mph, when he heard a slight "clunk" from under the truck. He said he didn't notice anything different until he got to the next stop light. From there when he accelerated it wouldn't shift from 1st to 2nd until about 3200rpm at light throttle. But the 2-3, and 3-4 shifts are fine (shift about 1800rpm as usual), and the TCC will lock like usual. When he went to leave later on he noticed he lost reverse too.

So we checked the fluid and it smells fine and it's in the "hot" area on the dipstick when idleing. Didn't notice any connectors loose or anything. The speedo and everything else works fine on it.

No reverse and delayed 1-2 shift seems to be the only problems.

Any ideas what might have happened? Any help will be greatly appreciated.

Thanks

 

he blew it up, nothing unusual, the Drum is broken. Pretty typical of 4L60E's...but typically unheard of just cruising. I'd bet he was beating on it....at least that's how they typically break.

Chris