Not a HUGE leak, but leaves a pretty good sized spot in the driveway overnight.

It appears to be coming from the transmission, as the transfer case usually checks full.

The transmission, adapters (Marlin), and transfer cases were all purchased used, appeared to be in excellent condition. The setup DOES make some gear noise, almost like it's talking to you.

I have my old transmission, but REALLY don't want to go through pulling the tranny again!

Just wondering what the usual causes are, and how severe the problem might be.

 

Forgot... do you have an auto or manual tranny?

Mine leaks as well, about the same level you describe. I have heard from others that this is somewhat common (hard to avoid) running duals. For me, it seems almost as if oil is escaping through the top, but I have both factory shift lever plates installed. Probably just the air movement blowing the oil around while driving.

I will be pulling mine as I do my 3.4 swap next week and hope to find the cause. I'll pass along any thing I figure out.

 

Common with duals, or just common with duals and a 5speed behind a 3.0?

 

I have heard of the leak issues with duals behind 4CYL as well. Not saying it should happen... hopefully we can come up with a solution.

 

crap.

okay, well, now I'm going to wait until this is resolved. Crap.

 

I had gear oil leaking out the top of my dual cases, enough to leave a good size spot on the garage floor.

After talking with Mike @ ORS quite a while it seems I may have caused the problem myself by putting grease around the shifter ball. The gear driven transfer cases were new to me and I learned from Mike that the only breather vent for the gear driven t-cases to vent air as it heats up is through the shifter holes. When I put grease around the ball and socket of the shifters I must have sealed up the breather on one or both. Appearantly I had sealed the front case better than the rear case because there was no leaking from the front case. My theory goes like this: When I sealed up the front case breather and was driving at highway speeds the air pressure was building in the front case and it pushed gear oil though the bearings into the rear case. There is a sharing of oil between the two cases. That overfilled the rear case with oil and caused it to blow out the top shifter hole breather vent which was breathing for both cases.

After taking all the shifters out and washing all the grease out in a parts washer, putting it back together the leak is gone now.

 

Interesting, I suppose that this scenario could also apply to the premature failure of the rear output shaft seal. I will try the cleaning thing; however, it does perturb me that I will not grease before insertion.

 

My leak truly does seam to be coming from the top... so maybe I also have a similiar "clogged breather" problem. Would be nice if it was truly something relatively simple to fix.

 

Of course if you are missing or have damaged one of these oil shield gaskets that could be a problem too:
http://www.marlincrawler.com/images/shiftbase_500.jpg

 

I will have to check closer and see if it's coming from the top ... which it may be because there is kinda oil everywhere, not a distinct leak location on the bottom...

 

i had kinda the same deal, but mine turned out to be a worn shaft on the output flange from the seal wearing it down over time. i thought it was coming from the t-case shifter, but on a road trip last week, i stopped at a store and could smell gear oil burning. i looked under the truck and could see where it was running down the t-case from the seal. there was a napa across the street that had the seal and when i put the seal in, i left it out about one eighth of an inch, and that got me home. that is my story and i am sticking to it....

 

I pulled my tranny today with the cases attached. At first inspection, it really seems like my leak is coming from the top. I do have a oil shield gasket in place and in good condition on both cases.

I did notice that on my tranny there is an additional gasket between the base plate and oil shield, where on my transfer cases they are both bare. Maybe the previous owner of the duals never used a gasket. The cases I bought were never installed, only assembled and ready to go.

Does anyone know if Toyota makes a transfer case gasket? If not, anyone see a problem using some RTV when I get to the point of putting the lever assemblies back in? I had a good amount of oil on and around both shields. It's definitely getting flung up there during driving.

 

Marlin uses lots gray RTV on both sides of that oil shield gasket thingy, so much that you pretty much have to replace the gasket if you take it apart for some reason, (like installing Roger's short throw shifters)

 

I'm cleaning up a transfer case (85 4Runner EFI) for my 3.4 swap and there are gaskets on both sides of the oil splash shield, in addition to some RTV the previous owner applied.

 

RTV it is then. Would be nice to solve that issue.

I'll post up when I get this thing back together and running again.

 

Wow - I will really have to check that out because I didn't put any gasket material in there either. Man I hope it's something that easy - don't even have to pull the cases to fix that!

 

Both r150 transmissions I have, and both stock chain drive tcases, had oil leakage around the shifters. I think it is the nature of the beast.

can't comment on the duals though, never messed with one.

 

I recently re-installed my transmission and dual cases. I had the 5 speed rebuilt 4 months ago and it recently died. Lost some teeth on the input shaft, luckily the shop stood behind their work and took care of everything. A few nights ago I re-installed the transmission and it went in like a dream. The transmission was in place and tight within 20 minutes. My next step was to install the t-cases. NIGHTMARE....I applied RVT where the two meet and had a hell of a time getting the two lined up. After about 45 minutes the two finally slipped together and I was rather concerned that the RVT had dried to much. I have since drove quite a bit and the merger is clean and dry, however, I get puddle from the rear tcase shifter base. That will be my next progect. Luckily I cut out a section of the floorpan and made a door for easy access when I initially installed the duals

 

Mine leaks and I do periodic level checks to avoid failure. The shifter bases are venting and the splash gards are in place as well. I'll just let it leak