Hey everyone. I did a front differential and transfer case fluid change myself for the first time. I did, however, run into a few problems that I would like to ask about. I am going to list them:

1. The transfer case was overfilled when I took the fill plug off. I thought of a possible seal problem with the trans, but the transmission fluid is normal and there are no red fluid leaks. Problem here?

2. After dumping the used gear oil and ATF into a jug I now use for oil recycling, I noticed that the bottom of the drain pan had a layer of fine "glitter" in it. I noticed this when the light from my LED headlamp (Please don't laugh. I do alot of camping and it is practical for working on the truck) hit the drain pan. The transfer case and front differential should have no more than 30k on the fluids. Does this mean I have a big problem or is it just like that because the drain plugs aren't magnetized and the metal is suspended in the fluid?

3. The front differential fluid was a dark/greyish yellow color out the drain plug (I was so relieved when I found out it had a drain plug.). Is this normal? I am not sure the level was normal to begin with and the 4WD was sometimes taking it's time to disengage unless the car is moving (Posi-Lok installation appointment is in 2.5 weeks). The front diff had major repairs done over the Christmas 2007 holiday because of a destroyed shift fork and other related damage. That is the history of this diff.

4. I did remove the rear diff fill plug (had to use WD-40, a torque wrench and a regular ratchet to break it loose) and I was horrified of what I found. I stuck my finger in the fill port and got BLACK LIQUID all over my finger (I am assuming that the level is okay in this case. Only 30k on this fluid also.). I am also going to have the rear diff fluid changed (along with a new cover) this week. This is a G80. Is there a chance that there is a major problem forming? I also did notice some liquid on the bottom of the differential, but I am not sure it was a leak (I drove the car through snow/mud a couple hours before that and there is old dried fluid all over the place that I am sure that was leftover from a repair done years ago by the previous owner.). I am sure that a major malfunction would have happened by now if the fluid was leaking and there is none on the garage floor. I did top off the fluid and it didn't take that much before it started to overflow. Maybe 1/8-1/4 qt? Can't really tell with the pump on the bottle. I did waste some of it because I either let it overflow or I missed the port. I am on my second quart and I have 1/4-1/2 qt left even after doing the front diff.

5. What are the appropriate torque ratings for the fill/drain plugs? I tightened them with the ratchet and then torqued them to between 10 and 12 ft-lbs. That was tight as I thought they were supposed to be. I didn't want to crack the unit.

6. I used Lucas 80W-90 in the diff (1/2 the price of Royal Purple and the name made it seem good enough at the time) and Valvoline MaxLife DEX/MERC ATF in the transfer case. Good choices?

I appreciate any advice given on this matter. Thanks.

 

1. Sounds like the front seal is bad, allowing the transmission to push fluid into the transfer case.

2. I wouldn't worry about it.

3. Sounds about right.

4. Depending on how long its been in there and what the gear lube was originally, it likely is perfectly normal. It won't stay truly clean.

5. Torque specs probably exist, but so long as you don't go nuts and the plugs seal, I wouldn't fret too much about it. Besides, if you keep on using your torque wrench to break fasteners loose, it may not be reading proper torque anyway.

6. If your transfer case is the 3-button switch, then Dexron-III or better ATF is perfectly fine. If you have the 4-button switch, then that is NOT ok.

 

Thanks. Let me answer your suggestions by number:

1. Oh no. How serious is this? I put Lucas in the trans not knowing I had I leak originally.

2/3. Ok thanks.

4. Ok great. Something to keep in mind

5. The plugs seem sealed okay. Just a bit tighter than I can make them with a normal ratchet. About 10-12 lb-ft. Thanks for the tip about breaking fasteners loose. I know not to do that again now.

6. It's a 98 with the 3 button switch, so it is in this case.


Also, is it possible to install a drain plug on the rear differential? I have a new 7.625" ring gear cover (seemed to be the one that would fit the shape of the existing cover) with a magnet.

 

If you do not correct the front seal, it could cause transmission fluid to be pulled into the vacuum system causing a rather large mess.

I believe that there are diff covers that have a drain or you could get out a drill & 1/4" NPT tap and put your own drain in the bottom of the differential housing.

 

Fluid pulled into the vac system from the transfer case? Wow. I assume that the only way to repair that is to remove the transfer case? Since I am having the Posi-Lok kit installed in a couple weeks, if I have the vac part of the 4x4 eliminated since it is no longer used (I could ask the shop to remove the hoses, actuator, cable and plug the hoses and switch at the transfer case?), will that work to prevent that? Thanks for the tip.

I will have to do that then and install a drain plug. Make it alot easier in the future to change fluids.

 

Doing the posi-lok setup would stop the fluid from getting into the vac system provided everything gets plugged off properly, however, it will not fix the problem of a leaking input seal.

The transfer case will need to be dropped to replace the seal.

 

Ok, then I will have the vac parts eliminated then. Dropping the T-Case is not in my budget at this time unless it is absolutely necessary. Thanks for the advice.

Also, just a side question: Where can I get another rear differental fill plug? Advance and Autozone don't seem to have it on their computers. Please tell me this is not a dealer only item.

 

Lowes or Home Depot... I think its just a 1/2" NPT plug with a recessed square indent for removal. You can either get one with a square protrusion or one that has a hex indent. Take your current one with you to compare the thread size.

 

Thanks. I will have to do that then. I saw one with a square protrusion at Autozone in the "HELP!" section, but only in a pack of 4 with different sizes (don't want to waste money on 3 plugs I don't need). I am going to check Tractor Supply, Lowes and Home Depot for the plug. It is just a pipe plug, but it doesn't need to hold pressure, right?

 

i would definitely change that input shaft seal as soon as possible. i didnt know mine was bad until just now and most of my transmission fluid ran out of there causing me to have crappy shifting points and almost no overdrive. the overflow into my vacuum lines caused my blower controls to clog up too.
very time consuming...