Replace front Seal in SM465 with Trans in Truck?

[JT58]

Hi all- my SM465 is leaking from the front seal. My engine is a 74 engine in an 87 truck and also leaking oil. I was going to pull the transfer case and transmission and replace the front seal and/or reseal the transmission. Since the engine is leaking oil anyway, maybe it's better to just get a period correct newly rebuilt 87 TBI engine and pull and replace the engine? If the engine is pulled, can the seal in the tranny be accessed and be replaced with the tranny in the truck? Maybe this is simpler approach than pulling the tranny and transfer case? And it gets me a period correct engine as well? I am also not sure if the seal is leaking due to transmission wear or the seal is old and just needs replacement. Either job is too big for me. And good shops to do this type of work are so hard to find in my area. And the ones that do so overcharge by thousands of dollars. I may have to have the truck trailered further north in FL to find a shop to do this. Just trying to find the simplest solution.

 

[nvrenuf]

either / or….

Both ways are a lot of work, the job can be done both ways, I guess I’d go the cheaper route of the 2.

May I ask why it’s important to have a “period correct” motor? Both can run on TBI. Visually, the difference is the valve covers and the dipstick (and the intake bolts for a really sharp eye).

 

[PrairieDrifter]

You're gonna be swapping engines often, if just because it leaks. They're squares, who cares what parts are on it unless it's all original low mileage.

 

[DoubleDingo]

I would recommend unbolting the bell housing, bracing the trans and transfer case in place, remove engine, reseal engine, reseal transmission, reinstall engine. If the clutch is iffy, meaning you don't know how many miles are on it or how long it's been in service, replace it with a clutch kit and resurface the flywheel while the engine is out. Then you'll have a sealed engine and transmission and a fresh clutch.