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Kawabuggy · 07-05-2018, 06:39 PM

I have not looked through the "4L80E/400" build thread that was referenced above, but I am a transmission builder/rebuilder by trade.

One thing we do for the rear case bushing is to use a C6 pump bushing in that position. It is significantly wider than the factory case bushing and as such has less chance of walking, or spinning, in the case bore. There is no mod necessary to the bushing as it gets plenty of lube. This, of course, is on the 1997 & later cases that lube through the center support, and NOT through the output shaft as the earlier units do. I can attest to thousands of units running this way with no issues related to this mod. This mod DOES NOT replace the necessity of rollerizing the gear train though. It simply adds a little more support for the weight of the gear train and is significantly less likely to walk or spin due to additional contact with the case bore. We also use a very slight amount of Red Loc-Tite in the bore before installing the bushing. Absolutely critical that you get the bushing in perfectly straight. Any tilt, or angle, on the bushing and you will not be able to drop the lower assembly into the case.

07-05-2018, 06:39 PM	#18
Kawabuggy Registered User Join Date: Jul 2018 Location: Houston, TX Posts: 16	Re: 4l80e Rear case bushing I have not looked through the "4L80E/400" build thread that was referenced above, but I am a transmission builder/rebuilder by trade. One thing we do for the rear case bushing is to use a C6 pump bushing in that position. It is significantly wider than the factory case bushing and as such has less chance of walking, or spinning, in the case bore. There is no mod necessary to the bushing as it gets plenty of lube. This, of course, is on the 1997 & later cases that lube through the center support, and NOT through the output shaft as the earlier units do. I can attest to thousands of units running this way with no issues related to this mod. This mod DOES NOT replace the necessity of rollerizing the gear train though. It simply adds a little more support for the weight of the gear train and is significantly less likely to walk or spin due to additional contact with the case bore. We also use a very slight amount of Red Loc-Tite in the bore before installing the bushing. Absolutely critical that you get the bushing in perfectly straight. Any tilt, or angle, on the bushing and you will not be able to drop the lower assembly into the case.