Do Diff Covers Work Or Are They Just Bling?

[MolaKule]

Originally Posted By: Snagglefoot
Just being able to change your diff oil without going through the mess of pulling off the rear cover might make it worthwhile for some.


for sure.

That's why I own two Nissans. Drain and fill pugs on every gear system.

 

[hatt]

Part 2

 

[hatt]

Not too much happens in this video. He said he'll have the results video mid September.

 

[ofelas]

Without going into the pros/cons of stamped vs finned diff covers, one could conclude that neither your F-150 nor your Jeep are capable of "Heavy Duty Towing".

Originally Posted by billt460
Both my F-150 and my Jeep both came with extra cost, "Heavy Duty Towing Packages".

 

[MolaKule]

Finned or not, if the cover has some increased capacity AND drain and and fill plugs, that is a plus.

 

[hatt]

Another video in the series.

 

[StevieC]

Hatt, that video was great. Thanks

 

[hatt]

It was pretty neat seeing the inside of the diff.

 

[StevieC]

Originally Posted by hatt
It was pretty neat seeing the inside of the diff.


Yeah, first time I saw that... Had an idea of what was going on but never considered the shape of the pan affecting the flow of oil. Makes sense though.

 

[02SE]

So it appears he's only referring to aftermarket Aluminum diff covers, and not OEM ones designed and speced by the engineers for use in trucks with specific GCVW ratings, and in performance cars that might be subjected to extreme use.

As I said before, if the engineers had determined that my truck could meet it's GCVWR with the standard stamped steel cover used on lower GCVWR trucks, they would have just used the stamped steel cover and saved some money.

 

[hatt]

Originally Posted by 02SE
So it appears he's only referring to aftermarket Aluminum diff covers, and not OEM ones designed and speced by the engineers for use in trucks with specific GCVW ratings, and in performance cars that might be subjected to extreme use.

As I said before, if the engineers had determined that my truck could meet it's GCVWR with the standard stamped steel cover used on lower GCVWR trucks, they would have just used the stamped steel cover and saved some money.
What truck do you have?

 

[02SE]

RAM 3500 4wd CC Dually, HO Cummins, Aisin, 4.10 gears, auto leveling rear air suspension.

The same truck without the HO Cummins, and Aisin trans, has a lower tow rating and GCVWR, and uses a stamped steel diff cover.

 

[hatt]

Neat. You have a pic of the cover?

The only factory aluminum covers I've noticed were on Nissans. I just figured they were swag like a chrome exhaust tip. They certainly aren't heavy haulers like a ton dually diesel.

Edit. I found a pic. Looks like the exact shape of steel covers. Aluminum with a lot of fins. I'm sure that does cool better than a stamped steel cover.

 

[clinebarger]

Originally Posted by MolaKule
Finned or not, if the cover has some increased capacity AND drain and and fill plugs, that is a plus.



Added capacity may not be beneficial at all.....

I've done extensive testing of deep transmission pans & found they do more harm than good, Especially if the vehicle can accelerate from a stand still quickly. Some of the cars I build transmissions for can cover 60 feet in 1.20 seconds. The fluid would climb into the geartrian, Aerate, Uncover the fluid suction port AND make the fluid temperatures run higher.

I realize this isn't an apples to apples comparison with a differential.......But lube needs controlled all the same & engineering on these types of aftermarket products is usually very poor.

 

[JLTD]

Cool thanks for all. Can't wait for Part III.

 

[02SE]

Originally Posted by hatt
Neat. You have a pic of the cover?

The only factory aluminum covers I've noticed were on Nissans. I just figured they were swag like a chrome exhaust tip. They certainly aren't heavy haulers like a ton dually diesel.

Edit. I found a pic. Looks like the exact shape of steel covers. Aluminum with a lot of fins. I'm sure that does cool better than a stamped steel cover.


The problem with the Titan is that when it came out, it had a Dana 44 with a stamped steel cover. The Dana 44 was arguably undersized for the application, and when people towed, the diffs would occasionally overheat and self-destruct. So Nissan put an Aluminum diff cover on for better heat dissipation.

 

[hatt]

Originally Posted by 02SE
Originally Posted by hatt
Neat. You have a pic of the cover?

The only factory aluminum covers I've noticed were on Nissans. I just figured they were swag like a chrome exhaust tip. They certainly aren't heavy haulers like a ton dually diesel.

Edit. I found a pic. Looks like the exact shape of steel covers. Aluminum with a lot of fins. I'm sure that does cool better than a stamped steel cover.


The problem with the Titan is that when it came out, it had a Dana 44 with a stamped steel cover. The Dana 44 was arguably undersized for the application, and when people towed, the diffs would occasionally overheat and self-destruct. So Nissan put an Aluminum diff cover on for better heat dissipation.

Weird. GM has used the 10 bolt rear for decades without major issues.

 

[CarbonSteel]

Originally Posted by clinebarger
Originally Posted by MolaKule
Finned or not, if the cover has some increased capacity AND drain and and fill plugs, that is a plus.
Added capacity may not be beneficial at all.....

I've done extensive testing of deep transmission pans & found they do more harm than good, Especially if the vehicle can accelerate from a stand still quickly. Some of the cars I build transmissions for can cover 60 feet in 1.20 seconds. The fluid would climb into the geartrian, Aerate, Uncover the fluid suction port AND make the fluid temperatures run higher.

I realize this isn't an apples to apples comparison with a differential.......But lube needs controlled all the same & engineering on these types of aftermarket products is usually very poor.
Any data you care to share that helps substantiate your point?

 

[MarkM66]

Looks like the stock one is best. As usual.

 

[clinebarger]

Originally Posted by 2015_PSD
Originally Posted by clinebarger
Originally Posted by MolaKule
Finned or not, if the cover has some increased capacity AND drain and and fill plugs, that is a plus.
Added capacity may not be beneficial at all.....

I've done extensive testing of deep transmission pans & found they do more harm than good, Especially if the vehicle can accelerate from a stand still quickly. Some of the cars I build transmissions for can cover 60 feet in 1.20 seconds. The fluid would climb into the geartrian, Aerate, Uncover the fluid suction port AND make the fluid temperatures run higher.

I realize this isn't an apples to apples comparison with a differential.......But lube needs controlled all the same & engineering on these types of aftermarket products is usually very poor.
Any data you care to share that helps substantiate your point?



I have all the data saved on a thumb drive, But it's just that.....Raw Racepak Logger data.

I logged....
G-meter (3-axis)
MPH
Engine RPM
Current Gear
Trans Forward Drum RPM (On 4L80E's)
Output shaft RPM
Main Line Pressure (Transduser)
Outlet Cooler line Temperature (Thermister)
Sump Temperature (Thermister)

*The Line Pressure would drop upon acceleration, Then work back up to ALMOST normal (Suction becoming uncovered).
*You could see the ATF was aerated from the foamy look on the dipstick, Thought it was from sucking air.....Relocated/Fabbed a suction tube that would pick-up ATF from the back of the pan.
*This helped the line pressure drop a lot but did not cure it completely.
*Fluid would still aerate.
*Fabbed-up a baffle around the pick-up tube to keep the fluid sloshing to the back of the pan......Fixed ALL the issues along with a 15 degree drop in max Temperatures.
*The ATF must have been climbing the back of the pan & getting into the geartrian, You can call this part of my findings speculation if you want!

Installed a stock pan & filter....Along with new frictions & steels in the trans because they were distressed.......This trans has lived for 3-years/500 passes since without issue.

***This is an extreme example (1000 HP put through a Trans-brake 4L80E & 10.5" slicks), But cost me A LOT of time that could have been put to use making money!