[nakman]

Well, was down swapping the gear oil tonight, and found a couple surprises. The first is my t-case is leaking where the speedometer cable attaches to it. This wasn’t really a surprise, since it’s been doing this a little bit for a while now, but tonight I noticed it had gotten a bit worse. So is there a seal or something that I can replace? I’ve been looking through my FSM but haven’t found anything yet… page number anyone? where tf is that index anyway. Picture below..

[nakman]

Second thing’s got me a little worried… my gear oil was green, not yellow like it was the last time I changed it (6 months ago in fact, maybe 5K miles?). Got me a little freaked out. My ATF is fine, in fact it was just exchanged yesterday and I was told the old ATF looked real good. That doesn’t surprise me considering it looked great 6 months ago too, when I did the 4 qt. drop & swap… just like it looked 6 months before that. The only thing I did differently was drove the last block home tonight in low range, just to "shake things up a little" before dropping the old gear oil. (no, CDL wasn't engaged)

So why would my gear oil turn green? I haven’t been through any water, just the car wash a couple times… where’s the breather hose supposed to attach? Hope it’s this simple… heading back down to the garage now. Sorry for the post first, search later approach. Anway here’s what my hand looked like after pulling the drain…

[landtoy80]

It is a O ring.
Does the oil smell burnt?

[nakman]

No, the oil didn't really smell burnt at all, just looked green. I was thinking that too, like half the gear oil had already oozed out, and I had like 6 oz. in there trying to keep everything lubed up and it overheated. I don't think it got too hot though, at least I hope not.

[landtoy80]

My new t-case turned the M1 oil dark after about a year.
What oil did you use?

[cruiserdan]

Yer gear oil is fine.

You need to replace the o-ring on the outside of the speedometer driven gear sleve.

As I'm home at the moment sipping on a bubbly delight, I can't recite the part number .

It is indeed an easy fix.

D-

[landtoy80]

Looked at the old t-case and there is a green paint on some of the parts.
Don't worry about it. But if you still worry, I will give you $800 cash for your 80 and I will do the worrying for you

[nakman]

You guys are too sweet, thanks. I checked my breather hoses and all seemed fine there, so maybe some water leaked in where the speedo cable is leaking? that's my theory at this point...

Kurt, was running Valvoling 85-90 somethingorother, but I switched all 3 tonight to M1 synth.. $68 bucks for 9 quarts, ouch, I've got 1 full one left over for the recovery kit. but it's worth it, right? keep your $800, perhaps a trade for the turd? mmm, ok perhaps not.

C-Dan, on the off chance you happen to look up that o-ring PN tomorrow, anyway you could make one of them show up at my house? And if your bubbly delight is a Milwaukee's Best Light then we have a lot more in common than I thought...

[landtoy80]

I don't think its water. The paint just dissolves over time in the oil.

[nakman]

just finished up with this little job, thanks again to all everyone that helped me out. Very easy and straight forward, like you said it would be.

I was a little concerned with the amount of dirt that was around the speedo housing, is this about normal? I was sure to wipe it all clean before reinstallation.

[nakman]

My Slee T-Case work shelf proved to be invaluable... I'm very glad I took advantage of the Halloween sale.

[nakman]

My gear oil was kind of green again, but very clean, as it should be since it was only a week old, I'm sure my t-case enjoyed its little synthetic oil flush this past week.

sooo.. I think I'm good to go, you guys agree?

[cruiserdan]

Looks good to me. That reminds me, I need one of those tool shelves too .

[DanKunz]

Hey CDan...send my one of those o-rings for my 91 please

[nakman]

So to give some of you a little closure, and to thank some others again, here's a little follow-up picture of my transfer case. Almost 4 months later and all is still well, no more leak. I hope this helps someone else down the road as they're combing through Sir Junk's FAQ archives... everyone.

[e9999]

when I was checking out an 80 a bit back, I noticed a leak around the speedo pickup.
Mentioned it to the dealer who said the whole assembly had to be changed. I asked why can't you just replace the Oring? He said, nope, gotta buy the whole thing....
sheesh... what's with this breed???? (fortunately, there is still a few good guys who are managing the parts department at some dealers, and a few good shops around , but other than that, the situation looks bleak.... :-\)
E

[Gumby]

To add to the FAQ:

My transfer case was leaking from the same general area. It would only really drip when parked nose up in my very steep driveway. it started after a wheeling trip where I hit my driveshaft hard a couple of times. I cleaned the area around the speedo well and found I was, in fact, leaking from the output shaft seal.

About a 2 hour job with the correct tools.

Pull the rear driveshaft from the front yoke. You don't need to pull it all the way out.

Remove the bolts around the tailshaft area. It's very large as the viscious coupler for the rear is in there. Pull the speedo cable and the two electrical connections.

Tap lightly to break the silicone sealant bond and remove the tail shaft.

Remove the first of three snap rings. Here is the proper tool needed I mentioned. You MUST have a good pair of outside snap ring pliers. They should have the flat ends, not the ones with holes in them.

Pull the v/c out.

Remove the next snap ring and pull the gear out.

Remove the next snap ring and push the output shaft out of the tail end of the housing. The bearing can stay in.

Remove the seal from the outside. It is now accessable with the flange out of the way.

Reverse to install.

Fill with Mobil 1 75W-90

No leaky. The seal is not generally stocked, but C-dan can git 'er for ya. your local parts goober might be overwhelmed by the request as mine was.

I got pics. i'll add them to the thread when I have 'em handy.

[Vitesse_6]

Hi all.
Any word on the Part # for the Speedo seal?
Sounds like a good time to do the Ujoints and the slip joint lube.
Thanks in advance

[landtoy80]

Yes, do check and clean the slip yoke.
If you don't see any grease on the shaft and/or muffler after greasing and then driving, you MUST take it apart and clean or you will put too much pressure on the t-case and diff pinion.

[concretejungle]

can we get the pics for this? Mine is leaking...

[little_joe]

For the leak at the transfer case where the speedometer gear is, I used some Permatex non-curing automotive sealant. I smeared a thin coat around the o-ring area, reinserted the gear, and haven't had a leak since. Because this is non-curing, you can pull and reinsert any time with the same results.

(Sorry for the bump, figured this might help someone.........)