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Leaky Transfer Case FJ40

AdamKFarmer

Hard Core 4+
Joined
Aug 29, 2011
Messages
556
Location
Denver, Co
Hey all, quick question on what would you do. I rebuilt my transfer case a few years ago on my '82 40 (thanks Marco!!) but since then there is a slow and steady leak form the case. I replaced it with the paper gaskets from Cruiser Outfitters with no sealant. Previously there was a ton of orange sealant that I had to scrape off prior to this. I bought a new gasket kit and was planning on trying again, what should I do differently? I thought the Toyota way was always correct, but after having re-plumbed my mini-truck and having to use FIP to prevent water leaking I'm thinking this might be a similar situation. I was thinking of spraying the gaskets with that spray gasket material to make them tacky and hopefully having a better seal. Thanks in advance!
 

Notyourmomslx450

Cruise Moab Committee
Cruise Moab Committee
Joined
Aug 4, 2014
Messages
3,202
Location
Westminster
I'd use the silicon. I rarely use paper gaskets anymore.
 

rover67

Rising Sun Member
Joined
Nov 1, 2007
Messages
9,291
Location
Boulder, Co
Is it leaking from where the case halves go together? That seems unusual, I've done maybe 5-10 split case rebuilds and haven't had one leak yet using dry paper gaskets.

If you want to use something on the gasket it's probably fine, I'd recommends loctite 574 over silicone tho. Just lightly cover the gasket with it upon assembly. You'll also want to check the output bearing preload and make sure it is in spec for used bearings when you reassemble even if you use the exact same gasket. The preload on the rear output bearing can change depending on the gasket thicknesses. This is why a more viscous sealant might be avoided and why I usually go dry. FWIW the 574 on a dry gasket I think will clamp down pretty much the same as a dry gasket... hell for that matter the silicone may also. Either way you will want the gasket rather than deleting it in favor of silicone only unless you want to reshim that output.

I have a TON of 574 if you want some.
 

AdamKFarmer

Hard Core 4+
Joined
Aug 29, 2011
Messages
556
Location
Denver, Co
Is it leaking from where the case halves go together? That seems unusual, I've done maybe 5-10 split case rebuilds and haven't had one leak yet using dry paper gaskets.

If you want to use something on the gasket it's probably fine, I'd recommends loctite 574 over silicone tho. Just lightly cover the gasket with it upon assembly. You'll also want to check the output bearing preload and make sure it is in spec for used bearings when you reassemble even if you use the exact same gasket. The preload on the rear output bearing can change depending on the gasket thicknesses. This is why a more viscous sealant might be avoided and why I usually go dry. FWIW the 574 on a dry gasket I think will clamp down pretty much the same as a dry gasket... hell for that matter the silicone may also. Either way you will want the gasket rather than deleting it in favor of silicone only unless you want to reshim that output.

I have a TON of 574 if you want some.

Marco! Thanks for chiming in, thought about calling you and asking but didn't want to be a bother. Yes it's leaking where the case goes together. Not horribly or anything, a few drops after driving it for a while. I went to go take a picture but it wasn't leaky since I haven't driven it in a few days since cleaning it off. I could use some 574 if you want to throw some my way! : )
 

shellb

Hard Core 4+
Joined
Feb 6, 2013
Messages
674
Location
Erie CO
I also have a leaky tcase in my 80. Would love if someone near here that could fix it.

Heck I could use a mechanic to do a few cruiser related things that I won’t get to.

Any takers!
 

AdamKFarmer

Hard Core 4+
Joined
Aug 29, 2011
Messages
556
Location
Denver, Co
Okay, i think I figured out the issue. The transfer case shift boot is loose and the seal isn't snug at all.
 

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rover67

Rising Sun Member
Joined
Nov 1, 2007
Messages
9,291
Location
Boulder, Co
Oh yes that has happened to me. You can try a little RTV on the seal OD to seal it up. I might try a new seal. Also after applying the RTV the seal May want to slip out a bit so put it on there and let it cure before driving it. You’ll want to hammer it in just far enough so it traps the boot but not so far you can’t get the lip of the boot under it.
 

AdamKFarmer

Hard Core 4+
Joined
Aug 29, 2011
Messages
556
Location
Denver, Co
Oh yes that has happened to me. You can try a little RTV on the seal OD to seal it up. I might try a new seal. Also after applying the RTV the seal May want to slip out a bit so put it on there and let it cure before driving it. You’ll want to hammer it in just far enough so it traps the boot but not so far you can’t get the lip of the boot under it.
I did order a new boot and seal from Toyota! Will try the rtv as well! Thanks Marco, also did you get a new number?
 

rover67

Rising Sun Member
Joined
Nov 1, 2007
Messages
9,291
Location
Boulder, Co
Same 901 number I’ll message you
 
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