Truck is approaching 200k, and since I dont know the history on it much before me, I thought I should freshin up all the fluids.

Ive heard that Synthetics in the Diff and Axles is a good idea to reduce alot of turning resistance.

What flavor of oils would you guys reccomend on an 01 F350 diesel
Will I need new seals for the axles?
How hard is changing the diff oil?
Any advice or comments?

Thanks and much appreciated.

 

The factory Diff oil is a synthetic. If you follow the manual for specifications you will be ok. If you don't have the manual there is one online at ford.

 

Ive put roayl purple 75w140 in my rear axle. Their was a humming with my old gear oil. (had it changed at the stealership). Then it was time to be changed again, i went out and bought the RP 75w140 and the humming noise stopped.

 

Thanks

When you changed out the rear for Royal Purple, what were the steps involved?
Ive never done it before but I assume you go buy the oil and a new gasket, pull the cover, catch the oil, re-install new gasket, put cover back on, and then use the check hole to refill the lube to correct level?

So I need to buy:
1) RP rear syn
2) Syn Diff fluid
3) Regular for front

Will napa know the weights I need or be able to look it up?

 

If you feel like spending the money you could buy a new diff cover like a mag-hyetc or ats. They are bigger to allow more fluid and better cooling. Also, they have an o-ring seal so you dont have to do the silicone thing again after draining the old one. They run about $275.

 

Np Rckeymntn. I went to advanced auto parts and bought the oil. They dont carry it so they had to order it from their distrubuter keystone automotive. It came in the next morning. You are better off buying the oil off line. (its alot cheaper!). I asked the guy which weight oil to use and he said 75w90 but then he asked me if i hauled anything. I told him yes and he recommended 75w140. He said it was thicker oil and would be better for ur rear end when towin.

Now with the parts ull need. U wont need a gasket.

1. A liquid rear diff sealer known as High Temp RTV silicone. (it is the gasket)
2. 75w140 royal purple gear oil. Ur rear end takes 3.5 quarts. So each bottle is a quart, so ull need four.
3. limited slip additive. (only if u have limitied slip) If u dont then for get about number 3.

What to do.

1. Take the pan and put it under the rear end. and loosen all of the screws, but dont completely take off the cover. This will let the oil seep out.

Now follow the instructions from this link.

http://guzzle.rbmicro.com/rdiff.html

BTW, is ur truck 4x4? The reason i ask, is because u didnt include that info in the OP. If it is a 4x4, then hear are the instructions for the front end.

http://guzzle.rbmicro.com/fdiff.html

BTW, When u put the sealer on the rear end and reattach the diff cover, dont fill the rear diff up with fluid just yet. Let it sit for a hour WITHOUT any fluid in it so the RTV silicone can dry.

When u add fluid to your rear end you will kno it is full when oil starts comming out of the hole where you are filling up ur diff.

Good luck and post u results. If u have any ques, just ask the forum or PM me!

 

EDIT: Never mind I eat hybrids beat me to it and did a better job.

 

Sweet, Step by Step instructions.....How can I go wrong

Thanks bro and I appreciate the help.
Owe you a beer.

 

No problem just ship the beer to ohio!! lol Glad to help u and let us kno how it goes. When u gonna change the fluids?

 

Im thinking this weekend would be the time to do it...although its negative degrees and will freeze my azz off.

Those big Axle covers from Mag look sweet...maybe I should order one and when it comes in, do the change.

 

That doesnt sound like a bad idea. Alot better then having a stock rusted out one

 

Do it, you already have the lift to show it off. As far as the negative degree weather, you are a braver man than me. It's been in the 30's down here and I don't want to do any wrenching on my truck.

 

Please talk me into it!
Need the big covers because of the lift yeah yeah...see what the wife (real boss) thinks of my latest reasoning.

Last weekend was cold so I squeezed the big rig into the garage and ran the Kerosene heater until i couldnt see my breath and then went to work.

I changed out the crap stock Rancho shocks for the 5100 bilsteins, and then went to work on the door locks which all didnt work.

Did the old Tin foil on the resistor trick and then all worked flawless after several hours of taking the 4 doors apart to get them out.

Since I was on a roll I Fixed a rear speaker that I wired wrong originally and then did the belt minder disable trick and programmed 3 remotes I got Off ebay to run the new door lockers.

I was tired and cold but got er done.

 

Remember, the front axle takes SAE 80W-90, the rear axle takes SAE 75W-140 Synthetic.

 

That link to Guzzles page shows he used the 75w90 synthetic up front, and
75w140 synthetic rear......Should I avoid that?

All I can see different is he had a dana 60 and mine is a dana 50