Transfer Case Leak 26K Miles - Rear Output Shaft

5 years and 10 months since purchased new but only 26,000 miles. just noticed during a routine inspection.

I was actually fishing around for one of the rubber grommets that falls off the engine beauty cover and normally comes to rest in the skid plates only to be greeted with this at the rear output shaft:

 

I think you meant to say 5 years, and 10 months? Looks like minor seepage - place a mat under vehicle where you park and monitor.

 

Yeah, I did mean 5 years 10 months. Edited.

 

That sucks! Definitely a leak. In my book it’s not seepage if it’s forming drops.

The output shaft seal might be a culprit, but there seems to be staining to the left side of the picture that almost looks like it could be leaking somewhere else too. Is that the only dripping you see?

 

From what I'm reading repair involves two seals and a bearing? Any specialty tools required?

I'm wondering what caused the seal to fail early and if more investigation might be needed so it doesn't fail again after a short time.

 

When my TC gave up the ghost, I pulled and replaced it with salvage. I never looked into tearing down my old one, so can’t give you much help there. Although, why would a bearing be necessary? Wouldn’t this just require pulling and replacing the shaft seal?

 

There might be a tool, or at least a specific procedure, for removing the nut that holds on the driveshaft flange.

 

Yellow tint was from the fringe of my LED wand light. don't see another source.

and yeah... it does suck.

Some have suggested an uneven/worn bearing surface is suspected of causing some of the early seal failures seen on 2018-2022 4Runners and Tacomas.

 

Is that the VF2BM transfer case on yours? Question for you, or anybody that knows for sure.

 

Rear output shaft seal leaks are pretty common on Toyota transfer cases. My 97’ had one.

 

Yep, VF2BM

 

FWIW, this is an open investigation by the NHTSA for 2018-2022 model years.

https://static.nhtsa.gov/odi/tsbs/2022/MC-10224177-9999.pdf

 

I’d bet that the lack of fluid dry rotted the seal.

 

Given that TSB document, it looks like the output shaft seal is what should be replaced. Without commenting on the theory of a bad bearing causing the leak, replacing the bearing appears to need disassembly of the case and messing around with all the gears and pins, and snap rings etc that hold the gears to the shaft. Looks like a pretty big job to go after the bearing.

Replacing the rear seal doesn’t seem that complex in comparison. Just checked a “special PDF” I found that indicates special tools to remove the nut that holds the driveshaft flange, and to pull that same flange from the output shaft. And a third tool to drive the seal. Were you planning to do this yourself? It looks like you could replace the seal without removing the TC from the vehicle.

You’re only 10 months out from the powertrain warranty. Maybe it’s worth a try to have Toyota cover it under goodwill based on that it’s a known problem. That said, if they’re jerks, they’ll probably charge you an hour of diagnostic time to tell you they won’t cover it. That will only really matter if you decide to fix it yourself.

 

It's full except for the film you see on the T-Case. There isn't any accumulation on the skid plate.

It has never sat for longer than two weeks without being driven.

 

This is an eye opening report from when I was a Master Tech with Infiniti, over 20 ears ago, I was advised that any leak, Back in 1990, was considered to be excessive and to be corrected under warranty. 2025, I would assume the story has changed?

 

I'll probably do it myself (assuming just the seals) but thinking about presenting to dealer since as you say, not that far out of drivetrain warranty on time and pretty low mileage along with the TT bulletin.

 

Thanks for details McSpaztron. Tools may be close to repair cost but if it's a weak link might make sense to go that route and do it myself. I would have what I need to do it next time too.

 

If you decide to go that route, snap a few pictures for the suckers that will be next in line. I saw the TSB and was a little bummed mine fell in the affected range. Then I thought, wait, my TC isn’t a 21!!!!

Then I looked and remembered I replaced it with a TC from a 2018 my4runner. Doh!

 

I would try a bottle of

$37 AT-205 Seal Leak Stopper 8 Ounce - 2 Pack

AT-205 myself. It's fixed lots of leaks for people.

 

I had it fixed by a local shop. It's my only vehicle, didn't have DYI time as I need to make a 500-mile trip this weekend.

Toyota, as expected, didn't want to help at almost 6-years despite low mileage and the NHTSA investigation ended in 2022 so they washed their hands.

Anyway, I'm starting to wonder if it might have been self-inflicted by applying too much grease to the rear slip yolk on my very first prop shaft lube back in 2019. I'm thinking too much grease in the might have limited drive shaft compression causing excess force on the transfer case output shaft resulting in premature seal wear.

I've removed both front and rear zerks bounced up and down and took it out on a BLM trail adjacent to my neighborhood. Nothing came out of either fill hole. Thoughts? How much excess would it take to cause a problem like that? First time before I knew what I was doing I put in 10-12 pumps with trigger grip style gun.

 

Over greasing the slip yoke is a really good point to consider. However, I would guess it can’t be that since none came out when opened it up and bounced the suspension. Even so, when I do the same, and grease does spooge out, it’s usually spit out by air pressure, not a solid column of grease that would hydraulically act on the transfer case. The air trapped inside the slip yoke would probably do a lot of cushioning.

Knock wood, but I’ve done a few aggressive slip yoke greasings on mine without leaks. To be specific. I put 50k miles on my first transfer case with no leaks. The current TC that I bought slavage with 50k miles, has gone another 25k miles without leaking.

 

That's what I'm worried about, a solid column of grease and no air gap. When I get back from my trip I'm going to disconnect both driveshafts, remove the zerks, fully compress the yolks to drive grease out and reconnect to make sure

 

No. More likely to be a mfg defect at the Tahara plant. They use the transfer case output flange as a sling point for dropping the entire powertrain onto the frame. Doesn't take much to distort the dust shield on the output flange or mar the sealing surface. GX460 shown, 4Runner similar:



My Tacoma's transfer case output shaft leaked after just 30k.

 

I’ve seen that pic before and felt like that could be a problem lol.