which synthetic for rear diff?

[spindlecone]

Scott
If you are going to remove the cover than I suggest you also get a couple cans of brake cleaner or berrymans and spray down the entire interior of the diff, side gears, spiders and all surfaces, will be alot of old crap you can remove,JMO

 

[aldive]

Every time I have dropped the cover, the inards looked pristine and there was no residue whatsoever.

 

[spindlecone]

Al
Prestine is in the eye of the beholder, when I put in my powertrax at 15 K miles, i had an 1/8th of an inch of sludge in the bottom of the diff, being ****, i removed it

 

[aldive]

Wow. What fluid did you have in it?

Mine have always been as clean as a new assembly.

 

[aldive]

Al
Prestine is in the eye of the beholder

Naw, pristine is like pregnant, it either is or it ain't....

 

[snocross1985]

I guess i will find out what it looks like tomorrow. I have a can of brake cleaner I can use if necessary.

 

[spindlecone]

Al It was OEM non LS oil most likely 90 wgt generic, at about 12 k miles when i installed the powertrax, Ring, Pinion, side gears and spyders were super clean as one would expect as they are in constant motion, the bottom of the punkin was full of crap, just what i found.

 

[aldive]

I see, mine have always had synthetic in em.

 

[Rhett]

It doesn't hurt to clean the inside of the rear diff cover and what you can reach in the gears with brake cleaner. It won't leave any residue and won't harm your diff, and won't corrupt the new fluid. I've done that for years when I change rear diff fluid, and never any noise, or problems whatsoever.

 

[snocross1985]

Ok, I am now fully sythetic with Mobil1 in the rear diff . It took me about 3 hours to do and was very easy to do. I did not use the friction modifier for the limited slip since Mobil1 says that it is not required since their sythetic has the additives in it already. The gears looked excellent, but the oil was pretty nasty. A couple tips for anyone doing this in the future:

1. When you get the diff cover off, brake cleaner is gold! I used a can to spray off the inside as best I could and the diff cover as well. Took out all the sludge and nasty crap that was inside.

2. If you do use brake cleaner this is very important; USE PROTECTIVE EYEWEAR! I found this out the hard way a few years ago. I made sure I had some safety glasses before I even got the can off the shelf. If some overspray or mist gets in your eye it hurts more than anything! It is very important that you protect your eyes and use it in a well ventalated area.

3. Now, when you have used your RTV Silicone to seal it all up and have bolted the cover back on (cross tighten), it is time to fill 'er back up. The plug is a pain in the arse to get off and is best removed using a 3/8" socket extentsion (the plug has a square hole in it). Now many people on here have said they used a pump or something to fill it back up. I, being very cheap, did not want to buy a pump if I didn't have to. So what I did is crawled under the truck after cutting the tip on the bottle of gear oil, put my finger over the hole so that when I tipped it it wouldn't spill. Than I removed my finger and quickly pushed the tip into the fill hole. It is not hard at all to do it this way at all. Once the tip was in I just squeezed the bottle until it was empty and repeated until it was full (takes a little more than 2.5 quarts of gear oil, more iff you spill).

 

[jared ajlouny]

so if i bought 3 quarts i would be fine?

 

[snocross1985]

I bought 3 quarts and had some left over in the 3rd bottle. So yes, buy 3 quarts and you will be set.

 

[Ford_Racing_Guy]

i've used 75w90 Valvoline synthetic with the L/S additive in my cars diff and haven't had any problems

 

[DocVijay]

With my SVo diff cover, I used 5 quarts of oil. Granted I spilled around a quart on myself and the ground, as I also did not feel the need to buy a pump (but now I will!). So it's more likely about 4 quarts total.

 

[aldive]

I have a 3/8 inch clear hose that attaches ( screws ) to the quart bottle. Never a mess. Simple too.

 

[DocVijay]

I have a 3/8 inch clear hose that attaches ( screws ) to the quart bottle. Never a mess. Simple too.

...and when I was at the auto parts store, I looked at that little tube and said, "Nah, that's not really necessary." Famous last words.

 

['96explorereddiebauer]

This is awesome information!!! Thanks very much!! I'll be changing both front and rear diff fluids and my tranny fluid and filter in the next few days. I've already bought 4 quarts of Mobil1 Gear Lube and Ford Motorsport Friction Modifier and 5 quarts of Maxlife tranny fluid and Motorcraft tranny filter kit, which includes the gasket.

Here's my question. Does changing the front diff fluid the same way as the rear one or is it a whole lot harder??

 

['96explorereddiebauer]

Well, I changed the rear axle fluid for the first time. Took me a total of 5 hours. Well, I had lunch and went to take my friend to the Toyota dealership during that time too. I used Mobil1 gear oil and Ford's Motorsport Friction Modifier for my LSD. I used a total of 3 quarts of gear oil. The result, it felt a whole lot smoother!!! I haven't had a chance to take it out on the highway yet since my rear brakes are shot but slow, 35mph driving is smooth!!! Thanks for all the tips guys!!! I'll be tackling the front axle tomorrow and probably change the tranny fluid tomorrow also. Thanks again!!!