Servicing the rear diff.
Freshman User
Joined: Sep 2009
Posts: 29
Likes: 0
From: Kabul, Afghanistan
There are also quite a few things that we change that Ford put in place as well. Just my opinion but I believe there is still plenty of room for what little expansion there would be and your gears are going to be in oil throughout a steep grade as well.
Lead Driver
Joined: Dec 2006
Posts: 7,092
Likes: 145
From: San Diego, CA
After pumping about a gallon in there (it's around 3 1/2 to 4 quarts IIRC), there's more than enough to sling around in there to keep everything coated.
Senior User
Joined: Sep 2008
Posts: 303
Likes: 1
From: Northern Calif
When I did mine,I put Redline synthetic gear oil and it had the friction modifier already in it, I also did not have a gasket. Used RTV. Works just fine. No extra additive needed. When you have the cover off it's also a good time to clean the VSS sensor.
Lead Driver
Joined: Dec 2006
Posts: 7,092
Likes: 145
From: San Diego, CA
At what point should the rear fluid be changed? My mechanic is ready to do it whenever I am ready.
But I only have 52,000 miles on my biggest baddest SUV on the road!
Wait a minute, it can't be the biggest and baddest; it ain't go no diesel. Second biggest baddest SUV on the road!
But I only have 52,000 miles on my biggest baddest SUV on the road!
Wait a minute, it can't be the biggest and baddest; it ain't go no diesel. Second biggest baddest SUV on the road!
I bought my truck and changed all the fluids so I would know what was in there and that I was starting fresh. The truck had 146K on it and the rear diff was black when I drained it (and boy did it stink!). I don't think that it was too bad (it was a ranch truck that pulled trailers for 4 years), but I definitely felt better after changing it and putting some fresh synthetic gear oil in there.
Junior User
Joined: Dec 2001
Posts: 66
Likes: 0
From: Ozark, MO
Mine chattered after a few thousand miles, but not very noticeable (with synthetic fluid and no modifier). If fact I thought it was a front wheel bearing making noise. When I had a load on behind it, the chatter was very noticable. I understand you can simulate the load by just riding the brakes as you make a tight turn.
Fleet Mechanic
Joined: Sep 2002
Posts: 1,388
Likes: 2
From: Greensboro, NC
If you're getting chatter after changing the fluid, run the truck through some figure 8 turns in a big empty parking lot before you do anything. Doing 3-4 large figure 8's gives the limited slip a chance to actually engage slightly due to the sharp turns and will ensure an even coating of fresh fluid on all surfaces. If you still have chatter after driving it then add small amounts of the friction modifier and repeat the figure 8's as you wont get an even coating of fluid in a short period of time without them. Normal driving over a few weeks will also do it but the figure 8's will accelerate it all and give you a chance to finish the job sooner. I used Amsoil Severe Gear and had a slight chatter and only need to add a little less than an ounce of their friction modifier to get it to stop.
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Tuned
Joined: Sep 2005
Posts: 493
Likes: 1
From: Portage, MI
If you're getting chatter after changing the fluid, run the truck through some figure 8 turns in a big empty parking lot before you do anything. Doing 3-4 large figure 8's gives the limited slip a chance to actually engage slightly due to the sharp turns and will ensure an even coating of fresh fluid on all surfaces. If you still have chatter after driving it then add small amounts of the friction modifier and repeat the figure 8's as you wont get an even coating of fluid in a short period of time without them. Normal driving over a few weeks will also do it but the figure 8's will accelerate it all and give you a chance to finish the job sooner. I used Amsoil Severe Gear and had a slight chatter and only need to add a little less than an ounce of their friction modifier to get it to stop.
Should I ad a little bit of the additive? I dont want to add it and screw something up if it is not the problem.
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Tuned
Joined: Sep 2005
Posts: 493
Likes: 1
From: Portage, MI
I have put around 75 miles on it since I did the oil change. I added a little over 3 1/2 quarts, just as the manual said.
Post Fiend
Joined: Mar 2009
Posts: 11,798
Likes: 14
From: Mt. Shasta California
OP
Not sure if it is a chatter without being there but I would fill the bango up to the fill hole because that is where it is designed by engineers to lubricate well and for proper cooling.
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Tuned
Joined: Sep 2005
Posts: 493
Likes: 1
From: Portage, MI
I filled it until it up til it started coming back out of the fill hole
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