Changing Differential Fluid
Thread Starter
|
Junior User
Joined: Jun 2003
Posts: 68
Likes: 0
Changing Differential Fluid
I've got a 2004 F150 4x4 with 3.73 limited slip with 30,000 miles.
When cold, the rear differential chatters/shudders when turning & accelerating from a stop.
It only does it when it's cold -- no noticeable problem when it's warm.
I'm going to change the fluid and put in friction modifier -- and see if that cures the problem; if not, I guess I'll have the clutches replaced (TSB 06-4-4).
A Few Questions:
1) Do I have to pull the rear cover? Or does one of the bottom cover bolts serve as a drain plug?
2) What grease? In a couple places I've read 75w90; but apparently Ford changed to 75w140 if the clutches are replaced. Should I use the old grease (75w90) with the old clutches, or should I use the new (75w140 grease) grease?
3) The Ford (Motocraft) friction modifier is the thing to use -- right?
4) If I have to pull the cover, what's the best "gasket goo" to use when I put it back?
Thanks
When cold, the rear differential chatters/shudders when turning & accelerating from a stop.
It only does it when it's cold -- no noticeable problem when it's warm.
I'm going to change the fluid and put in friction modifier -- and see if that cures the problem; if not, I guess I'll have the clutches replaced (TSB 06-4-4).
A Few Questions:
1) Do I have to pull the rear cover? Or does one of the bottom cover bolts serve as a drain plug?
2) What grease? In a couple places I've read 75w90; but apparently Ford changed to 75w140 if the clutches are replaced. Should I use the old grease (75w90) with the old clutches, or should I use the new (75w140 grease) grease?
3) The Ford (Motocraft) friction modifier is the thing to use -- right?
4) If I have to pull the cover, what's the best "gasket goo" to use when I put it back?
Thanks
Elder User
Joined: Jul 2006
Posts: 611
Likes: 0
YOu will be wasting your time and money on fluid change, it already has full synthetic oil with fricton mod. there is a know problem with the clutch packs but I don't have the TSB now ford recommends the diffs are lubed for life unless in deep water.
Elder User
Joined: Dec 2007
Posts: 680
Likes: 0
From: Michigan
As Lineman said, you have full synthetic. You probably have the HEFP or something like that. It is the 75w140 weight and that's what you need. THe HEFP was used for about 6 months across all trucks for "fuel economy" but it caused more axle whine issues than it was worth and Ford went back to straight syn with fricton modifier.
Several people on here have changed their lube and eliminated their shudder for a while. Either way, you need to drop the cover completely off. Clean off the surfaces and get the black rtv that's for differentials. Best bet is to used the Ford modifier. Having said that, at 90K, I changed all my diff lube with Royal Purple, but it's up to you to used what you want. If it were my truck and I was keeping it, I would change the clutch packs while I had the cover off. Just my $0.02...
Several people on here have changed their lube and eliminated their shudder for a while. Either way, you need to drop the cover completely off. Clean off the surfaces and get the black rtv that's for differentials. Best bet is to used the Ford modifier. Having said that, at 90K, I changed all my diff lube with Royal Purple, but it's up to you to used what you want. If it were my truck and I was keeping it, I would change the clutch packs while I had the cover off. Just my $0.02...
Thread Starter
|
Junior User
Joined: Jun 2003
Posts: 68
Likes: 0
Twinsdad98 …. Thanks for the information. With 30K on the clock and no heavy use or towing, I'd think the clutch packs might still be OK.
I think I'll change the fluid and stick in 4oz of the friction modifier; if that doesn't fix it, I'll stick in another 4oz; and if that doesn't fix it -- I guess it'll be "clutch time".
I've never had a limited slip apart -- not sure how big a deal it is. Anybody got a website or cheat-sheet that walks you through the process of changing the clutches?
I've got an almost identical truck, that's an '08 with just a couple thousand miles. It also has a very subtle chatter in the rear end -- not nearly as pronounced or annoying as the '04, but you can tell it's there. Is a little chatter normal, or do I need to drag the '08 back to the dealer?
Thanks
I think I'll change the fluid and stick in 4oz of the friction modifier; if that doesn't fix it, I'll stick in another 4oz; and if that doesn't fix it -- I guess it'll be "clutch time".
I've never had a limited slip apart -- not sure how big a deal it is. Anybody got a website or cheat-sheet that walks you through the process of changing the clutches?
I've got an almost identical truck, that's an '08 with just a couple thousand miles. It also has a very subtle chatter in the rear end -- not nearly as pronounced or annoying as the '04, but you can tell it's there. Is a little chatter normal, or do I need to drag the '08 back to the dealer?
Thanks
Senior User
Joined: Apr 2008
Posts: 411
Likes: 0
From: Fort Collins
IF you really want to change the fluid, you do NOT have to drop the cover...You can suck the fluid out using a pump you can buy at Harbor Freight...You do have to add a friction modifier though.
For the guy with the 08 like mine; hell yes, take it back to the dealer unless your shop is authorized to do warranty work like the one I work at for Ford.
For the guy with the 08 like mine; hell yes, take it back to the dealer unless your shop is authorized to do warranty work like the one I work at for Ford.
Elder User
Joined: Dec 2007
Posts: 680
Likes: 0
From: Michigan
There was an issue with clutch packs on the 04s that caused shutter on start ups and making turns that's why I suggested the clutch packs. There's a tsb out there..
Once you change your fluid and add the modifier, take it out and do several figure 8s in both directions to get the new fluid an modifier through the clutch packs. That will normally eliminate the concern.
Once you change your fluid and add the modifier, take it out and do several figure 8s in both directions to get the new fluid an modifier through the clutch packs. That will normally eliminate the concern.
