Did I cook the rear end?

[GAllen]

We just took a trip from So Cal to the Oregon coast, GVW @ 21,000 lbs. When I got back I noticed the paint on the rear diff cover was flaked off and the cover rusted. It was still new looking before we left. I took the 6% grades as fast as it would go, and there were several of them. Do I need to change the fluid right away?

 

[CumminsWill82]

How many miles on the truck? If it were mine i'd paint the diff cover cause i like my diffs painted to keep rust away and i chang the fluid. There is a TSB stating that you can use 75 w 140 synthetic. if you go that route use MOBIL1 not valvoline syn gearlube, that stuff foams like there is no tomorrow.

 

[JRD]

Is there any type of "whining" sound or droaing sound coming from the rear? If not, your probably ok. And besides if your rear diff fluid got really hot you would know it, that stuff stinks to no end when it gets hot. If you never smelled gear lube and there is no noise... your just fine. But if changing your fluid would make you feel better, certainly there is nothing wrong with some fresh lube in the diff.

 

[CumminsWill82]

BTW check my thread about AAM rearend problems.

 

[Nate]

I run Valvoline oil in the diffs of both my truck and Jeep and I've never had a problem.

 

[GAllen]

No noises, smells, or anything abnormal. Just flaked paint. Sounds like an aluminum cover and fresh fluid will be fine.

 

[CumminsWill82]

i just think valvoline foams a little to much

 

[LesStallings]

We just took a trip from So Cal to the Oregon coast, GVW @ 21,000 lbs. When I got back I noticed the paint on the rear diff cover was flaked off and the cover rusted. It was still new looking before we left. I took the 6% grades as fast as it would go, and there were several of them. Do I need to change the fluid right away?

It seems that the paint "cooks off" many of our differentials. There is a thread somewhere that discusses it. I change the differential fluid exactly as the manual requires and have never had a problem.



But YES, the paint is cooked off. I would not get worried unless the fluid come out bad.



Once I get set up to do more of my routine maintenance, I'll most likely change to a new cover, or at least paint mine and use a quick drain arrangement.

 

[rrausch]

The problem could also be poor surface prep prior to painting. Also the EPA has mandated pretty lame paints for many years now. The paint coming off is probably more due to those things than heat.

 

[klenger]

The problem could also be poor surface prep prior to painting. Also the EPA has mandated pretty lame paints for many years now. The paint coming off is probably more due to those things than heat.

Agreed.



[Adding useless text here to make my message long enough to be accepted. ]

 

[GAllen]

Thanks guys.

 

[Tony T.]

if you go that route use MOBIL1 not valvoline syn gearlube, that stuff foams like there is no tomorrow.

I would figure a over-fill to cause a foaming problem. Even though I have not used Valvoline I'm sure it's still good lube if filled to specs.



Tony

 

[LJFiler]

My rear axle looks like you describe and I thought the same thing. I have only 7,000 miles on my 05. I thought that I had gotten it hot so i checked the fluid and it was 3/4 quart low from the factory. The fluid looked and smelled fine. I believe that after taking a closer look you will find that the paint on the axle is just coming of because of the lack of good prep work before painting.

 

[JasonH]

We just took a trip from So Cal to the Oregon coast, GVW @ 21,000 lbs. When I got back I noticed the paint on the rear diff cover was flaked off and the cover rusted. It was still new looking before we left. I took the 6% grades as fast as it would go, and there were several of them. Do I need to change the fluid right away?

I wouldn't worry. I pulled a 28ft toy hauller 280 miles in 90deg heat, AC on, up hwy 15 out to Vegas. Yes paint flaked off but I just sanded it and recoated with some high-heat paint. Looks good as new. Oil change with Mobil 1 syn. No noticeable wear or discoloration on gears & oil looked good.

 

[MLee]

It sounds like "verify your fluid levels your self before driving your new truck" has gone by the wayside. They ship the fluids low in the differentials and the dealer is supposed to check and bring up to the proper levels. If asked they will tell you they have, but Many are not, they don't want to even after they deliver it to you. That is why the "pre-delivery" check list was devised. I don't think any body used it. took about 4 hours to do. But do your self a favor when you take delivery of your new truck, ASAP check those fluid levels. I am not an expert, just relaying what has happened with the third gen trucks.

Marv.

 

[JAlderman]

If it makes you feel any better, my 99 Ford SD with the viseon 10. 5 has done the same thing and it came with 75w140 syn. It has 131,000 miles on it and a rough life.

 

[wedone]

My 05 had 1500 miles on it and the rear diff paint looked like it was soaked in salt water. This was after hauling a 8K load up the Sierras in high heat. I thought I overheated the diff. After looking closely, it looked like crappy prep before painting. I took it to the dealer and they told me it was normal. I can believe it because I already painted the driveshaft do to "thin paint"

 

[MMeier]

Just put a Mag-Hytek on it and be done with it, also adds another 4 qts too!!

 

[WhiteSheep]

My differential paint baked off on the first long hard towing trip I took. I repainted it with high temperature engine paint and have not had a problem. I prepared the surface by washing it at a high pressure car wash and going over it with a wire brush. If anything else flakes off, I just shoot it with a little more paint. BTW, there was no sign of a problem when I changed the gear oil. I am using AMSOIL now. It is also important to note that the fill level is BELOW the drain hole, not even with it as is common. It is easy to overfill AAMs.



Whitesheep

 

[Buffalo]

Foaming Gear-oil

Regarding the "Foaming Gear-Oil" issue, how can you tell if your gear-oil IS foaming?



Joe F. (Buffalo)