Rear Diff Cover for Cooling..

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Wheeler

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I’ve never really thought of this before tbh… but I was thinking of changing my gear oil as it hasn’t been changed in a year & a half when the new 4.56 gears went in. I got home last nite after a 120mile tow trip… pull about 70mph entire way.. got home & put hand on stock diff cover…. Damn it was A Lot Hotter than I expected. I see b&m, g2 ect make cooling diff covers.. I did quick research, but is one preferred over the other? I have a 14 bolt rear end heavy half, so “assume” 10.5 ring gear..
 

stutaeng

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Should be 9.5" 14 bolt 6 lug semifloat axle. Heat is normal; after all, you are transferring power across. Actually, the entire drivetrain heats up when you drive and most people don't pay attention. Those are the ponies that are lost between your engine flywheel and the wheels: friction....in the form of heat.

I personally don't think you'd gain anything with the finned diff covers. Even the GMT400 heavier trucks run just a standard diff cover. I think it was recently that the Ram 2500/3500 trucks that started running those fancy finned aluminum covers. But in the aftermarket world they make you think you need anything the sell. Just my opinion. They do look pretty cool though.

Maybe get an infrared thermometer or something and check the differential fluid temperature before and after and report back with readings?
 
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1997

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infra red thermo says rear diff hotter than trans when I checked.
didn't except that.
i change my diff fluid frequently, every 25k km's.
 

DonYukon

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Honestly If you want my opinion its a waste of money. the only reason I bought diff covers for my lifted truck was for rock protection. as stated you probably have a SF 14 bolt. Unless you do a lot of high RPM exercises for prolonged periods of time you dont need to worry. actually changing the fluid is the best protection as the heat overtime breaks down the cooling and lubricating properties . Ive wheeled with guys who's buggies axles would literally be boiling ( you could hear it) they would just change the fluid afterwards and most of them have had zero issues with the actual carriers and lockers. most of their failures are either by shock load and unloading or half shafts
 

L31MaxExpress

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Should be 9.5" 14 bolt 6 lug semifloat axle. Heat is normal; after all, you are transferring power across. Actually, the entire drivetrain heats up when you drive and most people don't pay attention. Those are the ponies that are lost between your engine flywheel and the wheels: friction....in the form of heat.

I personally don't think you'd gain anything with the finned diff covers. Even the GMT400 heavier trucks run just a standard diff cover. I think it was recently that the Ram 2500/3500 trucks that started running those fancy finned aluminum covers. But in the aftermarket world they make you think you need anything the sell. Just my opinion. They do look pretty cool though.

Maybe get an infrared thermometer or something and check the differential fluid temperature before and after and report back with readings?

Nissan recalled the Titans in about 05 or 06 built prior to that point and switched them from 80w90 and a stamped steel cover to the finned aluminum cover and 75w140 synthetic oil. Dodge also recalled my 2006 Ram and switched from 80w90 to 75w140 when it was about 1 year old but no finned cover. Both manufacturers were having problems with rear end failures at that time from overheating and destroyed bearings (300+ hp fullsize 1/2 ton trucks were a new thing then). I use 75w140 synthetic in ALL of my rear ends now.

That being said I have a finned cover on both my vans. Not only does the differential stay cooler but it holds more oil (from memory my 10.5 now holds about 7qts) so it takes alot longer to get hot when you really load it uphill.With the finned cover and the synthetic oil it stays much cleaner between changes. It used to get diesel black between 24,000 mile changes and smelled like burned peanuts and no longer does that.
 
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DonYukon

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Nissan recalled the Titans in about 05 or 06 built prior to that point and switched them from 80w90 and a stamped steel cover to the finned aluminum cover and 75w140 synthetic oil. Dodge also recalled my 2006 Ram and switched from 80w90 to 75w140 when it was about 1 year old but no finned cover. Both manufacturers were having problems with rear end failures at that time from overheating and destroyed bearings (300+ hp fullsize 1/2 ton trucks were a new thing then). I use 75w140 synthetic in ALL of my rear ends now.

That being said I have a finned cover on both my vans. Not only does the differential stay cooler but it holds more oil (from memory my 10.5 now holds about 7qts) so it takes alot longer to get hot when you really load it uphill.With the finned cover and the sybthetic oil it stays much cleaner between changes. It used to get diesel black between 24,000 mile changes and smelled like burned peanuts and no longer does that.

my best friend had a 2006 Titan. I remember his axle overheated and failed but he told me it was due to axle seals failing prematurely causing fluid to get low and that was the reason.

Then again that was so long ago my memory might be skewed.
 

454cid

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I wouldn't worry about it. Maybe change to synthetic fluid like GM did in 99.

Last time I changed my gear oil in the back, I used conventinal 80w90. I purchased it about 10 years prior from TSC, and still had some left. I topped that off with some gear oil that my uncle had that was old enough to have been made out of fresh dinosaurs.

I also installed a new GM cover kit I found cheap on ebay..... new OEM cover, gasket, and bolts!

I should probably check the oil level as my pinion seal is leaking.
 

L31MaxExpress

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I wouldn't worry about it. Maybe change to synthetic fluid like GM did in 99.

Last time I changed my gear oil in the back, I used conventinal 80w90. I purchased it about 10 years prior from TSC, and still had some left. I topped that off with some gear oil that my uncle had that was old enough to have been made out of fresh dinosaurs.

I also installed a new GM cover kit I found cheap on ebay..... new OEM cover, gasket, and bolts!

I should probably check the oil level as my pinion seal is leaking.
I broke the spider gears in the 8.5 that came stock in my Express van shortly after swapping to the 4L85E and starting to tow with it regularly. When I tore into it the spider gears were the least of my worries. The axles, axle bearings, pinon bearings and ring and pinon were all blue from overheating (fluid level was not low and I had less than 90K on it) and the whole rear end was trashed. Swapped it for an 9.5 that I had redrilled 5 on 5 and ran with it. I have since swapped the 9.5 for a 10.5 with added fluid and a finned cover for better cooling.
 
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