I've got my 4 speed out to fix an annoying drip, replacing both front and rear seals.  Spent an hour or so cleaning up the input shaft housing, old Permatex on gasket area, and sealant on threads and washers.  Threads go into case, so FSM calls for sealant on bolts, but not much else for help.  Ready to put back together, and obviously don't want it to leak.

What is the best practice folks have found to get this leakproof?

Thanks!

If you have a new shaft seal installed then just clean surfaces and a new gasket should do it.

Here's an odd thing I ran across once though - the clutch fork pivot pin threads leaked fluid.  It took me a while to figure out the fluid ran down the fork and off the end of it to the ground.  A weird leak.  If you had that out, or even if you didn't, I would use some thread sealer on the threads.  The lock washer is not a sealing washer.

Also, don't forget the countershaft bearing shim.

Hopefully you noticed when removing the old seal that the seal is shall I say inverted. Meaning you drive it in upside down from the outside of the cover. Hope that makes sense. I used Permatex Anaerobic sealant on the gasket per @dave wm recommendation. Worked fine for me.

  On 12/7/2023 at 8:44 PM, Zed Head said:

the clutch fork pivot pin threads leaked fluid.

Good point, will remove and seal.

  On 12/7/2023 at 8:57 PM, Yarb said:

Hopefully you noticed when removing the old seal that the seal is shall I say inverted. Meaning you drive it in upside down from the outside of the cover. Hope that makes sense. I used Permatex Anaerobic sealant on the gasket per @dave wm recommendation. Worked fine for me.

Yep, spring side towards oil.  Here's what I've got.  Bolts to be torqued to 12-15 ft/lbs.

Might as well pile on with more stuff.  How does the nose look, where the throwout bearing rides?  They do wear, but you have the cast iron cover so it's probably fine.

And don't forget to run the clutch disc up and down the main shaft to be sure it moves freely.

  On 12/7/2023 at 10:04 PM, Zed Head said:

How does the nose look, where the throwout bearing rides? 

Looks good and smooth. Measures out to .004-.005 clearance for the throwout bearing.

Went to check the vent to make sure it was clear, but looks as though these don't have one.  Kind of odd, air has to go somewhere.  Maybe built into the shifter rod seals?

DOH!  As I was torquing it down, I noticed there is a vent on the top of the shifter cover.

Now the fun part, getting trans back in.  Seems like it was a lot easier when I was younger.