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Gasket sealer on bell housing to gear box

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MarkA

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I am re-sealing the transmission to stop big oil leaks. The largest is the joint between the gear box and the bell housing. It looks like the box has been apart in the past, probably when the OD was changed. Which gaskets need sealant? And what sealant is good to use? It seams that the bell housing shouldn't use a sealant since it uses crush shims to hold the input shaft bearing/main shaft tight, and you don't want to increase the gap. It did have a light coat of regular Permatex on all gaskets previously...

Mark
 
MarkA said:
I am re-sealing the transmission to stop big oil leaks. The largest is the joint between the gear box and the bell housing. It looks like the box has been apart in the past, probably when the OD was changed. Which gaskets need sealant?-------------- All of them.

And what sealant is good to use-
A light coat of Halomar should do you just fine.

It seams that the bell housing shouldn't use a sealant since it uses crush shims to hold the input shaft bearing/main shaft tight, and you don't want to increase the gap. It did have a light coat of regular Permatex on all gaskets previously...

Mark
Click to expand...
--------------------------Fwiw--Keoke
 
I used hylomar on the gasket too. As Keoke says .. a light coat .. which is not always easy but keep spreading it around until it is thin and leave no clumps. Make sure you check/replace if necessary the rubber pad (limits the shift rod travel) that fits in the recess in the bell housing. BTW, most of my leaking was coming from the gearbox front seal (located in the bell housing) .. you are probably changing both front and rear seals but just thought I'd mention it.

Cheers,
John
 
You might want to check torque after 24-48 hrs when using hylomar. I found it seems to permeate through fiber gaskets and relaxes bolt torque somewhat. Out of the tube it has a solvent that evaporates off over time.
 
Hi John,

I thought that the leaking was comming from the front seal and wicking. But after looking inside the bell housing, the front seal was not the major source (although a contributor). The larger leak was at the bell housing to gear box joint. I am replacing both shaft seals, all gaskets, and the mounts and bushings. I didn't see the shift rod rubber pad. I will check for it...

Thanks,
Mark
 
Hi John,

When I got home, I checked it out. It is there, full of oil, and hard. Should the pad be hard or a bit soft. It is softer that the metal itself, but...

What material did you use for a replacement pad? I am replacing the synchros this weekend with the help of a friend who is an offroad/racing transmission professional. Well, I'm reading the manual to him while he does the work! Is there anything else to look out for?

Thanks,
Mark
 
Hi Mark,

My apparently original pad was hard and cracked. I'm sure they were originally softer much like tire rubber that hardens with age. I cut a new shape from a some type of oil filter gasket that I had (wanted to make sure it was material that would stand up to hot automotive oil). You may need to cut two and assemble with RTV gasket adhesive to get the right thickness. I also used a little RTV to glue the pad into the recess to make sure it stayed put. This might have been overkill but I recall seeing evidence of contact cement on the old part and in the recess.

There are some tech articles at the following sites with some gearbox and OD overhaul tips.

team net healey tech tips

read the one called 'the wire trick'

OD rebuild
 
Hey All,

I received a new gasket set from Moss yesterday. The new gaskets are a lot thicker than the originals. I am sure they will seal up better than the originals, but what other effect will the thickness have? Anyone have experience with them and their effects? Should I be looking for more shims before the re-sealing starts?

Thanks,
Mark
 
Stretch said:
You might want to check torque after 24-48 hrs when using hylomar. I found it seems to permeate through fiber gaskets and relaxes bolt torque somewhat. Out of the tube it has a solvent that evaporates off over time.
Click to expand...
Hylomar has been through some confusing changes in ownership/distributors. There is a variety available which is solvent free thus non hardening see "advanced formula" below.
https://www.hylomar-usa.com/_resources/_html/products.html
It is similar to the Hylomar that Permatex was marketing a couple of years ago.
D
 
I appreciate the info on hylomar. I used it on my transmission with high expections of stopping numerous leaks. You can imagine my disappointment after pulling the transmission, rebuilding it and then having leakage again at most joints, using new gaskets and hylomar exclusively. Had I know it came from the 1960's....
 
MarkA said:
Hey All,

I received a new gasket set from Moss yesterday. The new gaskets are a lot thicker than the originals.----

Yep,somtimes they be green too!
I am sure they will seal up better than the originals,

Of course they will.
but what other effect will the thickness have?--- None
Anyone have experience with them and their effects?----Every one that has rebuilt a tranny in the last 10 years

Should I be looking for more shims before the re-sealing
starts?--It will be OK just torque it up tight.

Thanks,
Mark
Click to expand...
---------------------------Keoke-- /bcforum/images/%%GRAEMLIN_URL%%/cowboy.gif
 
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