Any tips on stopping a leaky TCase front output shaft seal?

I've been having a leaky transfer case for the past year. Brought it to the shop twice to fix the leak coming from the top where the stick is but I ended up fixing it myself with a little rtv gasket maker after they didn't fix it for the second time. Then she started to leak from the front output shaft. I got busy and didn't get to the repair until this last weekend. I did put off the repair because I had to do a little digging to find the correct part number (90311-41012) and accidentally ordered this one too (90311-41020). I drive a 1998 3.4l 4x4 Manual Transmission xtra cab Tacoma with around 306k miles.

After I finally took off that front driveshaft and got done messing with the staked nut, the original seal was falling apart and definitely needed to be replaced. I was a little confused on which part number was correct but i figured 90311-41012 was the correct part because it actually fit but i could press it into place by hand with my finger tips and i thought i would have to seat it with a hammer and pvc pipe around it. the part 90311-41020 looks almost exactly the same but has a slightly bigger diameter of 1-2mm and was peeling away the plastic on its outer edge when I tried to seat it so i stuck in the 90311-41012 part and it stopped for a day but is leaking again. The part looks correct but I think it is supposed to fit a little bit snugger than what my fingers can press in.

Any advice for me to properly seal my output shaft?

I was thinking about comparing the OEM seal to some aftermarkets to see if i could get that snug fit I think i'm missing.

 

You did use your VIN when looking for parts. If indeed it is the original Transfer Case.

Did you clean the transfer case and lube your seal?

Unless your doing 2 finger push ups The seal should not slide into place with your fingers.

Your going to need to measure the TC bore ID and compare with the seal OD to see just what your looking at.

Transfer Case vent open so the case can breathe?

 

Which seals did you replace?



As for leaking around the shifter, you have a couple of points to look at -

Which area are you seeing the leak from?


If the leak is around the shifter itself and not on the base where the tcase is, then you're looking at replacing this - its notorious for crumbling apart and is most likely due to be replaced -

 

@jpcutshall - What he said, always try to use your VIN to confirm you're ordering the correct part#.

 

the seals i replaced on the tcase diagram are 36111B (the one i suspected a leak from) and i also replaced 33309D (the little seal in the flange).

I did verify the part# with my VIN on toyotapartsdealdotcom and i did clean around the area a bit and lube the new seal (36111B). I will check on some toyota dealerships website after work today and update.

I did fix the leak around the shifter awhile ago and also replace the shifter bushings so I no longer have that problem.

I do think my breather could be clogged but am not sure how to check/ replace. But will update thisnpost later with the breather parts i bought and some
pictures.

 

If the seals are not driven in properly, they will leak. As @Bivouac mentioned, shouldn't be able to slide the seal into place with fingers alone.

This is the way it should sit -





you don't need a fancy SST from toyota or seal driver to do it (although it sure makes it easy), use a brass drift and once its started go evenly around the circumference of the seal until its flush.

 

Confirmed that the parts fit my vehicle by VIN#.

I reordered the same part and plan to measure both diameters @Bivouac suggested.
All of my research points (googling 36111B) me to this part number (90311-41012) which is compatible with my VIN.


I do have another question on if this is actually the breather for the transfer case or transmission? And any advice on replacing it (brute force i'm guessing). I do have the correct part to replace it. I call it the transmission breather in the images but I am not totally sure after reading this thread.


Also here is a picture of the leak.


Going to try and replace the seal again whenever the new seal and nut come in, But I will first try and figure out replacing all of these 25 Y/o breathers to see if that helps.

 

So that is in fact a breather. I was going to replace it myself, in fact I ordered a new one. Tried to remove the old one and gave up. Asked @Speedytech7 about it and he explained those are press-in breathers. I chose not to mess with it, removed the cap to it and connected some fuel line to it and ran it up to the engine bay where my other breather lines are at.

the leak is definitely the seal. Give it another go. If it’s not seated correctly or if it’s pushed in too far it’s going to leak.

 

I got to replacing the seal again today and from my observations the seal wasn't sitting flush and is meant to fit and there is no damage to the metal surface the seal sits against. There are a couple knicks on the outer edge but the seal doesn't touch that. There does appear to be som gunk/residue left over from the old worn out seal and Ima do my best to clean that up.

 

Usually they leak from where they seal around the shaft not where they sit in the bore. But if you're sure it was leaking from where it is pressed in the bore you can smear some RTV around the edge before pressing it in.

 

Yeah I'm pretty certain it wasn't coming from the shaft (pictured).

Just put some rtv on it and got it flush with the tcase. feeling pretty confident about it now.