Rear diff cover
Posting Guru
Joined: Jul 2003
Posts: 2,222
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From: East Central Florida
Dick,
I've had mine off a couple times in 225K Miles, it's just a plastic cover. I cleanly bead it with black RTV, let the RTV cure until it's almost set, then bolt it back in place. Same bolts same cover, different fluid & RTV. I use black so people don't see red or blue and start asking a lot of questions about my differentials A4WDs have 2 of 'em.
DON'T PUT RTV UP IN PLACE UNTIL IT"S SET ENOUGH SO PIECES DON"T FALL INTO THE REAR END.
FBp
I've had mine off a couple times in 225K Miles, it's just a plastic cover. I cleanly bead it with black RTV, let the RTV cure until it's almost set, then bolt it back in place. Same bolts same cover, different fluid & RTV. I use black so people don't see red or blue and start asking a lot of questions about my differentials A4WDs have 2 of 'em.
DON'T PUT RTV UP IN PLACE UNTIL IT"S SET ENOUGH SO PIECES DON"T FALL INTO THE REAR END.
FBp
Last edited by FordBoypete; Jun 8, 2006 at 10:05 PM.
Postmaster
Joined: Sep 2003
Posts: 4,452
Likes: 1
From: Southern California
Originally Posted by FordBoypete
Dick,
I've had mine off a couple times in 225K Miles, it's just a plastic cover. I cleanly bead it with black RTV, let the RTV cure until it's almost set, then bolt it back in place. Same bolts same cover, different fluid & RTV. I use black so people don't see red or blue and start asking a lot of questions about my differentials A4WDs have 2 of 'em.
DON'T PUT RTV UP IN PLACE UNTIL IT"S SET ENOUGH SO PIECES DON"T FALL INTO THE REAR END.
[/B]FBp[/B]
I've had mine off a couple times in 225K Miles, it's just a plastic cover. I cleanly bead it with black RTV, let the RTV cure until it's almost set, then bolt it back in place. Same bolts same cover, different fluid & RTV. I use black so people don't see red or blue and start asking a lot of questions about my differentials A4WDs have 2 of 'em.
DON'T PUT RTV UP IN PLACE UNTIL IT"S SET ENOUGH SO PIECES DON"T FALL INTO THE REAR END.
[/B]FBp[/B]
Senior User
Joined: Feb 2004
Posts: 389
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From: Rochester, NY
I'd bet they suggested replacing the cover because it is plastic. It may not be as forgiving to bolting and rebolting down. Maybe they got brittle and cracked when removed over time or something. I think, though, as long as there are no obvious cracks, holes or gouges in it, then it'll be fine...
Postmaster
Joined: Sep 2003
Posts: 4,452
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From: Southern California
Originally Posted by Torsen Rick
I'd bet they suggested replacing the cover because it is plastic. It may not be as forgiving to bolting and rebolting down. Maybe they got brittle and cracked when removed over time or something. I think, though, as long as there are no obvious cracks, holes or gouges in it, then it'll be fine...
Posting Guru
Joined: Jul 2003
Posts: 2,222
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From: East Central Florida
I will tell ya what on rod & Cyl head bolts, REPLACE THEM like the OEM Manual says ! 
They stretch out 1st time they're torqued and heated to normal op-temp, then next time they just stretch too much. Thus in time they result in uneven torque & pressure and things fail. Heads warp, rods stretch/ elongate or let loose through the block etc.
Don't ask how I know that. . . .
FBp
They stretch out 1st time they're torqued and heated to normal op-temp, then next time they just stretch too much. Thus in time they result in uneven torque & pressure and things fail. Heads warp, rods stretch/ elongate or let loose through the block etc.
Don't ask how I know that. . . .
FBp
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Senior User
Joined: Feb 2004
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From: Rochester, NY
Yes, but diff cover bolts are not torque-to-yield. They actually don't torqued much at all, otherwise the sealant would squish out... So, I can't think of a good reason to replace them unless they're damaged.
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Posting Guru
Joined: Jul 2003
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From: East Central Florida
I do it by letting the RTV cure a bit, so it will form but not squish out and I use the used bolts as I said up front on this thread.
I was making the point above, that "hard torqued" bolts & fasteners these days, or lately it would seem, fatigue after their 1st use, even when stage torqued and then re-checked after use. . . . "they jest don't make'em like they used to."
But I believe we all agree that's not relevant with differential case covers for standard application usage. . . . .
FBp
I was making the point above, that "hard torqued" bolts & fasteners these days, or lately it would seem, fatigue after their 1st use, even when stage torqued and then re-checked after use. . . . "they jest don't make'em like they used to."
But I believe we all agree that's not relevant with differential case covers for standard application usage. . . . .
FBp
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Lead Driver
Joined: May 2003
Posts: 9,303
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From: Lyndonville, Vermont
Well its back together and all is fine. I did rear brakes and changed the pinion or spider gears cause someone had two different size tires on the rear. They were the same size but one was 1.5" circ diff. Pinion shaft wear was the result..
Dick
Dick
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Joined: Oct 2011
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From: Redding CA
I was surprised to see that my 96 AWD rear end, traction lok, has a plastic cover.
When I change out the synthetic fluid next time, I will probably replace it with a metal one for better cooling, plus replace the filler plug with a magnetic one. I just did fresh synthetic fluid gasket and blue silicone. When I asked @ Napa they said there was no listing for the front Dana gasket and just use Blue Silicone.
Front is next with synthetic AFT Mercon, Rear I run High Performance 75-90 GL 5 with anti slip additive added, used it in my other Traction Lok just fine, Royal Purple.
When I change out the synthetic fluid next time, I will probably replace it with a metal one for better cooling, plus replace the filler plug with a magnetic one. I just did fresh synthetic fluid gasket and blue silicone. When I asked @ Napa they said there was no listing for the front Dana gasket and just use Blue Silicone.
Front is next with synthetic AFT Mercon, Rear I run High Performance 75-90 GL 5 with anti slip additive added, used it in my other Traction Lok just fine, Royal Purple.
Post Fiend
Joined: Apr 2005
Posts: 5,720
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From: Washington state
Dana spec'd all the 28s, IFS and solids, for 75w90 GL-5 hypoid gear set lube. Far better gear face loading protection. It was one of Ferd's not better ideas shoving their Mercon in them to increase mpg to meet CAFE.
Run a full real synthetic PAO/ester based 75w90 since the Aero front 28 is so shielded from cooling air flow and has such small case capacity. Seals, bearings and gears will outlast the van then.
Critical to not use the thin to lose ATF if towing, the 28 will get hotter than a firecracker in summer heat.
Put in a drain bolt while you have the front diff cover off, you'll see why after the first time. Change often
Run a full real synthetic PAO/ester based 75w90 since the Aero front 28 is so shielded from cooling air flow and has such small case capacity. Seals, bearings and gears will outlast the van then.
Critical to not use the thin to lose ATF if towing, the 28 will get hotter than a firecracker in summer heat.
Put in a drain bolt while you have the front diff cover off, you'll see why after the first time. Change often
Lead Driver
Joined: Sep 2003
Posts: 7,016
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From: SoCal
When I filled the front D28 axle with Mobil 1 75W gear lube, it would gush out of the vent tube after every drive. I refill again to the fill hole on the side of the case, and again, it would gush out. I suspect it's overheating enough to expand out the tube so much shoots into the vent hose, all the way up its full length and spill out, making a mess. When I started to refill with ATF, it stopped doing that.
Posting Guru
Joined: Jul 2004
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From: Mitchell, SD
When I filled the front D28 axle with Mobil 1 75W gear lube, it would gush out of the vent tube after every drive. I refill again to the fill hole on the side of the case, and again, it would gush out. I suspect it's overheating enough to expand out the tube so much shoots into the vent hose, all the way up its full length and spill out, making a mess. When I started to refill with ATF, it stopped doing that.
Front drive axle fluid may leak out of the vent under some driving modes on some vehicles. This may be caused by the design of the vent.
ACTION:
Install a revised front axle cover assembly which incorporates a baffled vent and plug the original vent. The service procedure is detailed in the Instruction Sheet included in the Axle Cover and Baffle Kit.
The Axle Cover and Baffle Kit (F79Z-4033-AA) includes the following:
- One (1) Baffled Cover
- One (1) Vent Hose
- One (1) Plug (for original vent)
- One (1) Instruction Sheet
PART NUMBER PART NAME F79Z-4033-AA Axle Cover And Baffle Kit
The part is obsolete and there are none out there.
Lead Driver
Joined: Sep 2003
Posts: 7,016
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From: SoCal
Thanks Nighthawk. Is that a replacement for the rear (front) cover of the axle housing? Is that where they put the new vent? I remember trying to pull off the cover when I was changing the lube, but gave up after a while because it was glued so tightly to the housing.
I will note that the axle didn't spew before I changed out the original ATF to 75w90 gear lube. And the leakage occurred during my normal drives, as in going to/from the same places as before, with no terrain changes.
I will note that the axle didn't spew before I changed out the original ATF to 75w90 gear lube. And the leakage occurred during my normal drives, as in going to/from the same places as before, with no terrain changes.