Matt69olds
Full Access Member
- Joined
- Jan 8, 2018
- Posts
- 2,540
- Reaction score
- 4,016
- Location
- Central Indiana
- First Name
- Matt
- Truck Year
- 81
- Truck Model
- GMC 1/2 ton
- Engine Size
- 455 Olds
Over the winter, my son and I have been fixing/updating some severely neglected things on his 92 Yukon. Things like replacing the crumbling dash, the falling headliner, rebuilding the suspension, installing a lift kit, installing heated back glass/mirrors, power seat, etc. One of the big items was fixing the “Kentucky flexplate” (missing teeth), occasionally the starter would make a god awful grinding noise.
Since flexplate replacement requires transmission removal, I decided to do some exploratory surgery on the trans. It shifted fine, and worked as expected, but after 220k I figured it might have some wear. It still has a factory converter, so I doubt it’s ever been worked on.
The autopsy went surprisingly well. The 3-4 clutches looked great, as did the band. Even the spacer plate was in good shape.
Imagine my surprise to find a broken drive shell! As many know, the drive shell is a known weak point on the 4L60/60e, when it breaks you no longer have 2nd, 4th, or reverse. Keep in mind, I personally backed the truck into the shop, so I know it had reverse!
The only thing I can figure is the Sun gear was still splined to the shell, even though the hub had snapped off. Meaning the remaining life of that shell could have been measured in feet. It was just barely hanging on!!
I would have been FURIOUS if we had just swapped flywheels, and first shift had no 2,4or reverse gears, and had to pull it out again.
Since flexplate replacement requires transmission removal, I decided to do some exploratory surgery on the trans. It shifted fine, and worked as expected, but after 220k I figured it might have some wear. It still has a factory converter, so I doubt it’s ever been worked on.
The autopsy went surprisingly well. The 3-4 clutches looked great, as did the band. Even the spacer plate was in good shape.
Imagine my surprise to find a broken drive shell! As many know, the drive shell is a known weak point on the 4L60/60e, when it breaks you no longer have 2nd, 4th, or reverse. Keep in mind, I personally backed the truck into the shop, so I know it had reverse!
The only thing I can figure is the Sun gear was still splined to the shell, even though the hub had snapped off. Meaning the remaining life of that shell could have been measured in feet. It was just barely hanging on!!
I would have been FURIOUS if we had just swapped flywheels, and first shift had no 2,4or reverse gears, and had to pull it out again.
