th400 second gear intermitent

ss3011 · 05-06-2009, 07:43 AM

If your 2nd sprag has been slipping, it probably has hurt the surface finish on both the inner and the outer races. The surface finish is critical to the ability of the sprag to hold torque. The outer race is easy to replace. The inner one is ground true after being pressed on the drum, and should not be replaced. Best practice is get a different/new drum that is in good condition. Also make sure you get a 400 drum instead of a 4L80-E drum. The balance procedure on the 4L80 part might have compromised it's ability to be able to spin at high RPM. OK for a truck, iffy for a race car.

05-06-2009, 07:43 AM	#20
ss3011 Senior Member Join Date: Feb 2002 Location: Southeast Michigan Posts: 909 Likes: 70 Liked 239 Times in 114 Posts	Re: th400 second gear intermitent If your 2nd sprag has been slipping, it probably has hurt the surface finish on both the inner and the outer races. The surface finish is critical to the ability of the sprag to hold torque. The outer race is easy to replace. The inner one is ground true after being pressed on the drum, and should not be replaced. Best practice is get a different/new drum that is in good condition. Also make sure you get a 400 drum instead of a 4L80-E drum. The balance procedure on the 4L80 part might have compromised it's ability to be able to spin at high RPM. OK for a truck, iffy for a race car.