Gear Oil / ATF Cross-Contamination

[Densetsu]

Last time changing the oil in the differentials was a pain -- not because of seized fill/drain plugs, but because of the fill hole locations. I think I wasted half a litre of gear oil because it spilled on the ground instead of getting into the differential. This time, I picked up a suction-style grease gun to make filling the diffs a breeze.



I also have a jug of ATF, and wanted to swap out the ATF in the transfer case. I had a quick look underneath, and the fill plug for the transfer case also looks like a pain to get to. What are the consequences of getting some gear oil in the ATF? Or if I clean it out with water and dish soap, anything bad about getting some water in the ATF? Should I just not use the same tool for filling the transfer case as I do for filling the diffs? Any tips on how to get to the transfer case fill plug?

[Towncivilian]

Use brake cleaner to thoroughly clean the gun.

[WPGQX4]

Or get one of these.
http://www.amsoil.com/storefront/g2039.aspx
It screws onto the bottle so you don't spill.

[ARKQX33V6]

Just did the same process. Gear oil in the ATF fluid for transfer case will thicken the transfer case oil but 80/90 with 10-15 oil will not thicken it very much. With your usual change interval what colour was the ATF fluid ? If still red no problem but if darker change the fluid next time in 1/2 the time.

I tie a 4 quart battle of ATF to the mirror, driver side, with a 3/8 clear plastic hose going down to the transfer case and fill it that way, then I use a hand pump same as in your picture suck up a tube full and shove, force feed the case. When it comes out instead of going in I'm done, anti seize the plug and send it home. The dripping of ATF makes it easier with only 1 squeeze of the vacuum push pull.

Both differentials are easy to use the bottles and squeeze them and keep filling them with another bottle, the only spilling is when the diff gets over fill.

I stiil have not found a way to change #6 spark plug, for me that is an impossibility even after 3 tries.

[Densetsu]

The diffs, especially the front one, were hard for me to get at with the 1L bottles when I did it with my last Pathfinder. The pump I bought made it *way* easier; I don't mind spending $15 on a tool that'll make an annual task easy. WPGQX4, do you have the pump you linked to? How big is the hose on it? The gear oil is thick, so it could take a while to fill the differentials, that was my only concern when I was picking out a pump to use.

This was the first time I changed out the diff oil on this Pathy, I bought it last summer and didn't drive it regularly until Christmas or so. I don't think the last/original owner changed the diff oil at all. He has all the service records, and there was no record of anything being done to the differential, transfer case, or transmission. The differential oil that I drained was a nasty dark grey colour. The magnet on the rear diff drain plug had a single small metal shaving on it. Hopefully there was no damage done.

I'll be swapping out the transfer case fluid hopefully this week or next, before I go for a few camping trips in the mountains this summer. Thanks for the feedback on the cross-contamination, I'll just let the gear oil drain out of my pump and then whatever is left in shouldn't matter when I use it for the transfer case.

I'll also say that my Pathy had a slight rhythmic vibration/shake when I was idling in gear, about once every second, which was annoying at red lights. Cleaning the TB and the MAF, replacing the air and fuel filter, re-learning the idle speed did nothing to help. A simple drain and refill of the transmission fluid, though, and now there's no vibration at all. The fluid wasn't dark brown or burnt-smelling, so I didn't even suspect it would be the problem. I just did it because I like knowing when it was changed last. I might do another drain and refill in the near future to try and get more of the old fluid out.

[WPGQX4]

Yes it arrived today. The hose is about a 1/4 wide. It has a pump so I'm not sure how hard it would be for regular gear oil to go through it. I'm an amsoil dealer so I order amsoil. The amsoil gear lube isn't that thick. Because it screws onto the top of the bottle, I don't think you could have any spills. Maybe out the end of the hose if your not carefull. You can just put the bottle on the ground and snake the tube into the fill side and pump away.

I just ordered all amsoil lubrication for my Q. Rear diff, front diff, transfer case, and transmission will all be changed over soon. Can't wait to see if there is any difference in the Manitoba winters here. With everything synthetic it should flow better.

Den the amsoil distribution center is in Edmonton. It wouldn't take you long to get one.

[Chris.m]

When I changed my Transfer case fluid and front diff fluid, I just used hoses. I had some Pex (Plastic equivilent of copper pipe) lying around, so I put one end in the fill hole and then held the other end higher than the fill opening, on the side/front of the truck (by the doors or bumper). After I finished, I just threw it away.

Here is a magnificent drawing in case my wording is terrible;