th400 second gear intermitent

gmonde · 05-06-2009, 06:39 AM

the snap ring was in place,i will upgrade the sprag to the 34 element ,and try it out ,like mentioned it all looks real good ,no metal chunks,presure testsed the clutch pack for clamping presure ,checked detent for valvebody spool operation,tom your right should have the aluminum drum, but it is not in the budget for this month,thanks for the replys ,all of the info very helpful

gmonde

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, 06:39 AM	#1
gmonde Senior Member Join Date: Nov 2007 Posts: 615 Likes: 56 Liked 165 Times in 59 Posts	Re: th400 second gear intermitent the snap ring was in place,i will upgrade the sprag to the 34 element ,and try it out ,like mentioned it all looks real good ,no metal chunks,presure testsed the clutch pack for clamping presure ,checked detent for valvebody spool operation,tom your right should have the aluminum drum, but it is not in the budget for this month,thanks for the replys ,all of the info very helpful gmonde

05-06-2009, 07:43 AM	#2
ss3011 Senior Member Join Date: Feb 2002 Location: Southeast Michigan Posts: 910 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.

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