Vehicle: Jeep Cherokee (non grand) Sport
Year: 1999
Mileage: 135 k

Looking to change both my fbi axel and rear differential fluids, the front and rear pumpkins if you will. I would really prefer to just pump out the oil fluids from the fill hole (instead of removing housing cover). Manual says the new lubricant should have "MIL–L–2105C and API GL 5 quality specifications". Also SAE 80W–90 for regular use and SAE 75W–140 SYNTHETIC for towing/ heavy use. I will be using it for normal use. Few questions.

The manual isn't clear but I am assuming both take the same type of fluid. Correct?

The manual says 1.48 L (3.13 pts) for the fbi axel but doesn't list the amount needed for the rear. I know you fill till it drips out the fill hole but I need to know an estimate on how much to buy.

The front is essentially the same as the rear for filling, just fill till it drips, right? Of course make sure car is level.

Any brand recommendations? I want something that I won't need to change in the near future. Amsoil seems popular but I am wondering if its overkill.

Any pump recommendations? Which auto store carries the better one?

Thanks

 

4.0L if that matter.

 

i run mobil 1 80-90 in my front and rear diffs all i bought 4 bottles last time and had about 3/4 of a bottle left when finished but if you are pumping it out which IMHO isnt that great of an idea and doesnt save to much time you wont need as much because you wont get as much out as for pumps i have a might vac i got from autozone i use to bleed my brakes but it could also be used to suck out fluids

 

If you're going to care enough about your Jeep to change the axle gear oil, care enough to do it right by removing the diff covers. Changing the oil is only half of the job. You need to reove the cover and wipe out the diff housing so you get ALL of that cruddy oil out and more importantly all of the sludge and metal shavings that may be floating around in there. You also need to take a look at you ring and pinion gears and the differential itself for any signs of problems or potential problems down the road. Along with your gear oil while at the auto parts store, pick a $1.00 tube of RTV sealant and that is the only added expense of having to remove the diff covers. I've never put a gasket on either of mine since the first of many times I've had them open abd I have never had a leak. Pulling your rear cover off may also reveil to you that your rear diff. has a LSD. If it does, it will require an additive to the gear oil for the LSD friction pads. Bottom line is if you're gonna do the job don't do it half...er...hearted.

 

If the rear dif has an LSD how do I know? What am I looking for?

This friction modifier, how much do I put in, or is it just a small bottle I'm suppose to mix with the oil before putting it in?

Whats the harm adding the modifier if I can tell whether I have an LSD?

 

If you pull the rear diff cover off to change the fluids just have a look. Or you can put the T-case in neutral and jack up one side and see if you can move the wheel by hand I believe. An open rear will spin, a LSD will not (at least not by hand).
If you have an LSD, add 1/2 the fluid, then pour in the whole bottle of friction modifier (read the label, it will say how much its supposed to treat), then fill the rest of the way. Once you are buttoned up and sealed, drive a few figure 8's and you will have the friction modifier worked in. Done!