th400 mainshaft same as early 80e?
Thread Starter
Joined: Nov 2013
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From: Portlandia
th400 mainshaft same as early 80e? getting ready to refresh the 80e in my "race car" and wanted to move to an early style gun-drilled IM shaft for more lube stability. My planets, sun components and case are Type 2 cases.
I'm told I can run the early 80e shaft with some small modifications to the OAL
I'm told I can run the early 80e shaft with some small modifications to the OAL
TECH Junkie
Joined: Dec 2012
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From: Iowa
knock .060 off the bellhousing end of the main shaft
Then be sure to run a roller hub so you move the thrust path OFF of the main shaft and onto the direct drum
Hollow main is an improvement over the solid main in a late 80e
yes, th400 shaft can be used if you follow the same rules
Then be sure to run a roller hub so you move the thrust path OFF of the main shaft and onto the direct drum
Hollow main is an improvement over the solid main in a late 80e
yes, th400 shaft can be used if you follow the same rules
TECH Junkie
Joined: Jun 2008
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From: Nitro Alley
Doug, you will also want to use a 1991-1996 Output-Shaft with the hollow Intermediate-Shaft.
You will then plug off the AFL tube to the Case-Bushing and the hole in the Valve-Body.
If your case still has the Boss cast into the Case for the Front cooler return fitting...
You can purchase a GM universal Pump that works with either Early or Late Lube-System.
I will explain to you a way to bring cooled Lube-Oil to the Overrun and OverDrive components...
Instead of using un-cooled Regulated Converter Feed Oil.
I should be posting about this soon in my 4L80E Lube-Circuit thread soon.
You will then plug off the AFL tube to the Case-Bushing and the hole in the Valve-Body.
If your case still has the Boss cast into the Case for the Front cooler return fitting...
You can purchase a GM universal Pump that works with either Early or Late Lube-System.
I will explain to you a way to bring cooled Lube-Oil to the Overrun and OverDrive components...
Instead of using un-cooled Regulated Converter Feed Oil.
I should be posting about this soon in my 4L80E Lube-Circuit thread soon.
Last edited by vorteciroc; May 5, 2021 at 01:45 PM.
TECH Junkie
Joined: Dec 2012
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From: Iowa
For anyone reading. what vortec mentioned is a good way to do it.
Probably the *best* way to do it
but not necessary...you can swap just the main and leave the rest. (although I'd probably swap to solid instead of fluted sun shaft bushings)
you can run the hollow main and keep the 80e output with no drilled lube hole. And you can feed the case/tail bushing with AFL oil still (it's stupid on principle...but it works)
Probably the *best* way to do it
but not necessary...you can swap just the main and leave the rest. (although I'd probably swap to solid instead of fluted sun shaft bushings)
you can run the hollow main and keep the 80e output with no drilled lube hole. And you can feed the case/tail bushing with AFL oil still (it's stupid on principle...but it works)
