2001 C5 Auto Transmission slipping
2001 C5 Auto Transmission slipping 
TECH Junkie
Joined: May 2012
Posts: 3,051
Likes: 716
From: Poplarville, MS
Have you checked the fluid level, is the fluid burnt, how many miles are on the trans, is the trans stock, how much hp are you putting through it? With the very limited info you have given, my idea is it's time for a rebuild.
TECH Junkie
Joined: Jun 2008
Posts: 3,203
Likes: 1,391
From: Nitro Alley
While a burnt/ worn 3-4 Clutch-Pack is common... it is not the only possibility.
Fluid condition and cleanliness (level of debris) is going to be a big factor.
-The Third-Accumulator Check-Ball Capsule may no longer be sealing.
-The Input-Drum Check-Ball Capsule for the 3-4 Clutch Apply-Piston may not be sealing.
-Either of the Shift-Valves/ Valve-Train may be getting stuck/ obstructed/ damaged by debris.
-There may be leaking/ cross-leaking Circuits in the Bore for the Servo-Assemblies.
-There may be restricted or blocked passages in the Separator-Plate.
-And several other possibilities.
Most of what I posted above will result in a 3-4 Clutch failure...
However, replacing the 3-4 Clutch Pack without finding the source/ cause of the 3-4 Clutch failure, will just cause a repeat failure.
Good luck!
Fluid condition and cleanliness (level of debris) is going to be a big factor.
-The Third-Accumulator Check-Ball Capsule may no longer be sealing.
-The Input-Drum Check-Ball Capsule for the 3-4 Clutch Apply-Piston may not be sealing.
-Either of the Shift-Valves/ Valve-Train may be getting stuck/ obstructed/ damaged by debris.
-There may be leaking/ cross-leaking Circuits in the Bore for the Servo-Assemblies.
-There may be restricted or blocked passages in the Separator-Plate.
-And several other possibilities.
Most of what I posted above will result in a 3-4 Clutch failure...
However, replacing the 3-4 Clutch Pack without finding the source/ cause of the 3-4 Clutch failure, will just cause a repeat failure.
Good luck!
