Seal/Gasket Between Transfer Case & Transmission

[YukonRog]

I know there's a gasket that goes between the two and have read that it's supposed to be a "dry" seal. Yet mine was covered on both sides with a gray material that's similar if not actually RTV. I've read to not use RTV. But most when separated have some ATF come out. And Permatex makes some sealants specifically for transmissions and transfer cases. I was buying materials for my TC rebuild and install and I bought some. Instructions read "Assemble and tighten until it starts to squeeze out then let it cure for an hour and then do the final torque. Let cure 24 hrs before adding fluid."
So some say use it, some say don't. Mine had it on it. What should I do?

 

[Bill 1960]

Dry in the sense there should be no ATF in that space. The transmission output shaft seal keeps trans fluid out of that space. The transfer case input shaft seal keeps transfer case fluid out. So the cavity should be dry inside.

I don’t think it matters whether you use sealant on that gasket or install it dry, I think it’s there to keep dirt away from the seals. Perhaps someone with the shop manual handy will chime in.

 

[YukonRog]

Dry in the sense there should be no ATF in that space. The transmission output shaft seal keeps trans fluid out of that space. The transfer case input shaft seal keeps transfer case fluid out. So the cavity should be dry inside.

I don’t think it matters whether you use sealant on that gasket or install it dry, I think it’s there to keep dirt away from the seals. Perhaps someone with the shop manual handy will chime in.

Thanks for chiming in Bill 1960. I read "dry" as in nothing on the gasket. But like I said, mine had something on it. And I would think there would be no fluid from the transmission in there but everyone that pulls the TC says fluid comes out. And it did. My transmission is a remanufactured one with only 7500miles on it so you'd think they would have at least replaced that rear seal.

 

[George B]

Just put it in without any sealant added.

 

[YukonRog]

Just put it in without any sealant added.

That's what I'm reading but I'm questioning why a "professional" shop would use something. OCD kicking in....LOL!

 

[Bill 1960]

That's what I'm reading but I'm questioning why a "professional" shop would use something. OCD kicking in....LOL!

Probably to keep a leaking seal contained so you’d not know it was there.

When I had my transmission replaced it subsequently leaked at exactly that spot. Which, to give credit to the dealer doing the installation, they immediately noticed. The transfer case needed a new front seal.

 

[YukonRog]

Probably to keep a leaking seal contained so you’d not know it was there.

When I had my transmission replaced it subsequently leaked at exactly that spot. Which, to give credit to the dealer doing the installation, they immediately noticed. The transfer case needed a new front seal.

Well the transfer case has a new seal going in and from what I read all the transmissions leak a little.

 

[rockola1971]

Well the transfer case has a new seal going in and from what I read all the transmissions leak a little.

They all dont leak a little. Only the ones that were improperly put together or put together with worn parts. The tranny output shaft and Tcase input shaft seal are there to keep respective fluid in. They will not prevent fluid from one or the other from entering. A leaking Tranny output shaft seal will eventually cause the Tcase to overfill and blow out its vent.

 

[YukonRog]

Okay so I have to replace the rear transmission seal then. It's leaking. Does the adapter for the Transfer Case have to come off the transmission? I can't find any YouTube videos or any written directions on my 1st look around on the old InterWeb. Is there one seal, or more? I need pictures! LOL! More work I guess. How hard is it to replace that seal?

 

[rockola1971]

Okay so I have to replace the rear transmission seal then. It's leaking. Does the adapter for the Transfer Case have to come off the transmission? I can't find any YouTube videos or any written directions on my 1st look around on the old InterWeb. Is there one seal, or more? I need pictures! LOL! More work I guess. How hard is it to replace that seal?

Your tranny is likely a 4L60E but this 4L80E video will do.

 

[YukonRog]

Your tranny is likely a 4L60E but this 4L80E video will do.

Thank you very much rockola71! Yes, mine is a 4L60E and this helps a lot. I spent the day chasing a hydraulic press and was grinning bigtime after pressing the bearings out and in on my Transfer Case. I also picked up some seal tools so hopefully I can remove that seal easily. As for installing, I've seen a video or two where the guy is using a piece of pipe or even pvc to set the seal in evenly. VS the videos where some use drift or socket extension and "walk" it in.

 

[Joseph Garcia]

Thank you very much rockola71! Yes, mine is a 4L60E and this helps a lot. I spent the day chasing a hydraulic press and was grinning bigtime after pressing the bearings out and in on my Transfer Case. I also picked up some seal tools so hopefully I can remove that seal easily. As for installing, I've seen a video or two where the guy is using a piece of pipe or even pvc to set the seal in evenly. VS the videos where some use drift or socket extension and "walk" it in.

Or, you can most likely borrow/rent a bearing seal driver kit from one of your local Autozone or equivalent auto parts store.

 

[YukonRog]

Or, you can most likely borrow/rent a bearing seal driver kit from one of your local Autozone or equivalent auto parts store.

Thanks Joseph! I'll have to check that out. That one would require a tube or pipe type driver because the shaft sticks out of the center of it.

 

[YukonRog]

Okay, NEED HELP GUYS! When I pulled the Transfer Case a lot of ATF came out right? I'm looking at this shaft that comes out of the transmission and there is NO SEAL. Now I get why the shop used soo much sealant on the adapter! What am I missing? Is there supposed to be a seal there? I really don't know what to do at this point. PLEASE HELP!

 

[YukonRog]

Double post...

 

[SamBurban]

Some fluid will come out and is normal. All the transfer cases I've pulled had transmission fluid in that area. I even had a new 4l80e from GM with the same thing. It does not mix into the transfer case. There is a gasket that goes there. GM part number 24245110 or dorman makes a replacement that is cheaper and works just as good. A lot of shops use RTV in between instead which also works just makes it harder to clean up next time you have the tcase out.

 

[YukonRog]

Some fluid will come out and is normal. All the transfer cases I've pulled had transmission fluid in that area. I even had a new 4l80e from GM with the same thing. It does not mix into the transfer case. There is a gasket that goes there. GM part number 24245110 or dorman makes a replacement that is cheaper and works just as good. A lot of shops use RTV in between instead which also works just makes it harder to clean up next time you have the tcase out.

Thanks for the response SamBurban, don't know why I'm not getting notifications on replies now. But I believe from what I've learned by scouring the internet you are correct. It's a bad design. Is there a drain so it goes back into the transmission pan? Why isn't there a seal there? There's a hole in the shaft.

 

[rockola1971]

Okay, NEED HELP GUYS! When I pulled the Transfer Case a lot of ATF came out right? I'm looking at this shaft that comes out of the transmission and there is NO SEAL. Now I get why the shop used soo much sealant on the adapter! What am I missing? Is there supposed to be a seal there? I really don't know what to do at this point. PLEASE HELP!

View attachment 349645View attachment 349644

The rear seal is indeed missing. You can see where the lip of seal rubbed on the shaft and you can see where the metal cup of the seal is walked into the inner diameter of the housing. Somebody ******* up. That is why you have alot of fluid in that adaptor section.

 

[frank1]

That adaptor cavity has trans fluid in it, that's why it leaks, also if the TC input seal fails it can dump the trans fluid out through the TC vent. We removed a TC, from my 02 Silverado HD plow truck, yesterday,,, gasket leak.

 

[Burban22]

2005 suburban. Removed transfer case and a lot like 1/4 qt of atf poured out of the extension housing between the trans and transfer case. Transfer case was normal level with the blue fluid. 4l60e was rebuilt 40k miles ago and no issues. Is this normal? If not what seal do I need and tool to install? Or just put it back together with new paper gasket between extension housing and transfer case?

Also when trans was angled down fluid was running out from the back of the trans didn’t see exactly but guessing where the shaft pokes through. No leaks when this was all together.