took off tcase, gear lube came out of tranny

i have a 98 with ax-15 and np231. i took my np231 off to put a new one on with a sye already installed and when i took it off, gear lube came out the back. i did some searching and found how to do a regular fluid change on an ax-15. that's pretty much everything i already knew. my question is, the fluid that comes out the back of the tranny isn't the same as the fluid that goes in through the normal fill and drain plugs, is it? and if not, where do i fill the back side of the transmission/front side of the tcase?

i already know about the GL-3 vs -4, -5 and stuff...

TIA

There'a a seal at the rear of the transmission that holds fluid in. Yours isn't working. There's not supposed to be an additional reservoir of fluid between the tranny and t-case.

Jim www.yuccaman.com

hmm good to know. how hard is that seal to change/what's involved? (i'll do a search on that in the mean time...) and, if that seal is bad, what's that going to do to my transfercase? probably nothing... because there's gotta be some kind of input seal to the tcase, and that case was a virgin. until i took it apart haha. anyway, thanks for the quick response, jim.

...so i drove about 130 miles after that happened :dunce:. i'm thinking that the tcase lost fluid but not all of it because the seal isn't at the very bottom of it. i'll have to get some and fill it asap. oh well.

Yup - seals at each end of the tranny and t-case. I haven't done the manual tranny, but I'm sure you can find some writeups online or find an FSM that can answer the how-to on replacing the seal. Was the fluid red (t-case) or grey/black and stinky (tranny)?

Jim

haha it was definitely the gear lube. i'm well aware of the difference, but thanks for the quick description; and that's about how i'd describe it too.

The transmission output seal isn't difficult to change (once you expose it,) but bear in mind that the transmission output seal usually seals against the transfer case input shaft, so you're going to "break the seal" once you unmate the transfer case. At that point, it's normal to lose fluid - and it's a good idea to drain the transmission before you jack down the transfer case anyhow.

So, you may not need to replace the seal - but, if you've got the transfer case jacked down anyhow, I'd go ahead and replace the transmission output seal (and the transfer case rear output seal - since you're there anyhow. The front output seal tends to hold up rather better, since it's sealing against simple rotation instead of rotation and slip.)

that's really helpful. thanks. i didn't take notice of the configuration of the output of the tranny when i had the tcase off, and i'm not really afraid to take it off again. i expected to have to in order to change the seal anyway. does the seal basically just press in once it's exposed?

i think i do need to replace the seal because even before i pulled the original tcase off, i had some gear lube leaking from the tranny in about that area. i think what caused that leak was my driving with driveline vibrations. that leak was really slow, so i never really did anything about it due to the fact that i knew i'd be swapping cases soon.

you mentioned that the tranny output seal has to seal against slip and rotation. when i had the tcase out and rebuilt it with the sye, i never noticed the tcase input shaft moving axially.

on a side note, how big of a deal is it if i can't get the GL-3? (it's a saturday night and all the real stores are closed and i need to drive 3 hours tomorrow, so i think i might be going to wallyworld and who knows what they're going to have in stock.)

asp387 said:

that's really helpful. thanks. i didn't take notice of the configuration of the output of the tranny when i had the tcase off, and i'm not really afraid to take it off again. i expected to have to in order to change the seal anyway. does the seal basically just press in once it's exposed?

i think i do need to replace the seal because even before i pulled the original tcase off, i had some gear lube leaking from the tranny in about that area. i think what caused that leak was my driving with driveline vibrations. that leak was really slow, so i never really did anything about it due to the fact that i knew i'd be swapping cases soon.

you mentioned that the tranny output seal has to seal against slip and rotation. when i had the tcase out and rebuilt it with the sye, i never noticed the tcase input shaft moving axially.

on a side note, how big of a deal is it if i can't get the GL-3? (it's a saturday night and all the real stores are closed and i need to drive 3 hours tomorrow, so i think i might be going to wallyworld and who knows what they're going to have in stock.)

Click to expand...

Perhaps I misstated - I was referring to the transfer case rear output seal working against slip & rotation - the transmission output, transfer case input, and transfer case front output all seal against slip only.

Replacing the seal is pretty simple - just pop the old one out (a seal puller hook makes this loads easier, but it can be removed with a flat screwdriver) and gently drive the new one in. The output shaft should be protruding slightly, so get a socket or a small pipe fitting that butts up against the rigid ring of the seal, and use that to drive the seal on (gentle strikes with a hammer should do - the 24-oz brass hammer I've got works quite well.)

In the AX-15, you have bronze synchronizer rings. GL-5 is antagonistic to yellow metals (like bronze) and you can end up actually dissolving the rings - you'll know it's happening, it looks like gold glitter when you drain the transmission. GL-4 borders on acceptable (don't run it too long,) but GL-3 is best. The problem is the sulphur added as an EP (Extreme Pressure) lube - it has an affinity for copper at operating temperatures.

If you can't get GL-3 or maybe GL-4, but you can get GL-1 or GL-2, I've found that adding LSD Friction Modifier assists GL-1/2 oils to lubricate in transmissions. Sort of "Afro-Engineering" a fix, but it's workable. Not acceptable, mind - but workable.

The confusion that most people have is that the API GL specs are not reverse-compatible like the API Sx/Cy specs are (except API SM...) so you can't sub in a "higher" spec where a "lower" one is required. All of the GL specs have to do with the amount of EP sulphur lubricant is present - as the numbers increase, so does the sulphur content. As the sulphur content increases, so does the likelihood of dissolving the yellow metal parts (brass, bronze, copper, ...)

Most stores do tend to have GL-3 and GL-5 on hand - there are quite a few manual transmissions still on the road with yellow metal parts, and most musclecars have yellow metal in the transmissions. So, GL-3 isn't likely to go away entirely anytime soon, although it will likely get rarer. I'd stock up on the stuff to keep around the shop for just this sort of occasion...

Like 5-90 mentioned, that seal runs against the xfer case input shaft. I'd replace it anyway, especially if you think it might have been leaking. It's probably time to drain and refill the tranny anyway. There is no front/back filling or seperate oil sections in the tranny. It's just the one fill hole.

Good to see you've already found the info on avoiding GL-5 gear oil. In my experience cheap GL3 oil, while having far less sulfur, still shifts very poorly in cold weather. I highly recommend getting a quality synthetic oil like Redline MTL (probably better than the MTL90, considering your location). Many have reported good success with AMSOil manual tranny oil. There have been a few posts of people recommending good old 30wt motor oil for very cold environments as well, but I have no personal experience with that.

this is really good info and everything i was hoping to hear. i'm glad to see that my chances at wally world are improving.



i found this picture, i'm assuming that black ring around the output shaft is the seal or something about that size..

i found a bit about the gl-5 and the bronze syncro rings and a bit about that, but the more detailed information is always appreciated. i didn't know the info about the -1,-2,-4 though.

to be honest, i don't care how well this works because i'm probably going to be only driving on it for a week until i have time again to put the new seal in. i just need for my tranny to not grind itself to pieces. i'm going to buy whatever works and won't eat my syncros. the leak is relatively fast at the moment and it's splashing all over my underside including the cat and muffler, so that smells just dandy. if you think gear lube smells, you should smell really hot gear lube uke:


lawsconcl - thanks for the info about specific lubes. i'll check it out and probably get something pretty good when i go to fill it for real

wow you're spoiling me, part numbers and everything :cheers:

when you say burnt tranny fluid, are you referring to atf or actual manual tranny gear lube, because that's pretty much what happened when it splashed all over my muffler.

btw, just got back from walmart. they didn't have gl-3, -2, or -1 so i got some 30 wt motor oil. it'll get me home at least. i was actually pretty impressed with the knowledge of the guy i talked to too. he had an MJ (granted, it was auto...) and knew exactly what i was talking about when i mentioned i couldn't use gl-5

I'm thinking burnt automatic tranny clutch packs. That smell just permeates everything. I'm surprised that you found someone knowledgeable at a Wallmart. I tried to drop my used oil there yesterday and the guy didn't even know that accepted used motor oil. I swear if he turned around he'd have seen the sign on the wall that said "return your used motor oil here".

yeah exactly, most of them have no idea what's going on but this guy seemed to know his stuff. this walmart also had some BFG KM2s and goodyear wrangler MT-Rs in stock so i think it was, on the whole, one of the better walmart car centers that exists.

i put 3 quarts or so in before the 5.5 hour drive that should have only been 3 hours. stupid little cars that can't handle snow... and it made it without complaining. i'm going to get the seal tomorrow or the day after and do it friday.

on the plus side, my check engine light went off randomly :thumbup: (i have a 98 with OBD II )