Manual Selector Shaft Seal, Allison 1000 | 2001-2023

Manual Selector Shaft Seal, Allison 1000 | 2001-2023

This is the genuine GM manual selector shaft seal, GM 24235861, for the Allison 1000 transmission behind the 6.6L Duramax in 2001-2023 Chevrolet Silverado and GMC Sierra 2500HD and 3500HD trucks. It seals around the manual selector (shift) shaft where it passes through the transmission case, keeping fluid in while the shaft rotates as you shift through the ranges. When it hardens or wears, transmission fluid seeps out at the shift linkage on the side of the case. It replaces the earlier GM 23010610 and 8657163.

Key Features

• Genuine GM 24235861 (replaces 23010610 and 8657163)
• 13.49 mm (0.531") ID x 19.15 mm (0.754") OD x 4.63 mm (0.182") thick
• Rubber seal
• Sold individually; one required per transmission

Benefits

A leak at the selector shaft is small at first but keeps dripping fluid onto the frame and exhaust, and a low fluid level is hard on the Allison. A new seal stops the leak at the source. The seal can usually be replaced with the transmission in the truck. Removing the old seal is the hardest part. Take care not to scratch the shift shaft, since a scratched shaft will leak past even a new seal, and drive the new seal in gently and evenly. Replace if worn or damaged.

Frequently Asked Questions

Can I replace this without removing the transmission?
Usually, yes. The seal is on the outside of the case at the shift shaft. Some techs find it easier with the front driveshaft removed on 4WD trucks.

How do I keep from damaging the shaft?
Avoid prying against the shaft with a screwdriver. A seal puller or removal tool is the safest way to get the old seal out.

Is this a genuine GM part?
Yes. This is GM part number 24235861.

Fitment

Fits the Allison 1000 transmission in 2001-2023 Chevrolet Silverado and GMC Sierra 2500HD and 3500HD with the 6.6L Duramax (LB7, LLY, LBZ, LMM, LML and L5P). One seal required per transmission.

What's Included

• (1) Genuine GM 24235861 manual selector shaft seal

For warranty information, see our Warranty Policy.