Rear Differential Oil Level

[DBurdett]

I have just had my 3500 Truck (2006) in the shop to have the rear pinion seal replaced (slight leak).

After the seal was replaced the technician told me I was overfilling my differential. The correct level I was told was just below the axle tubes.

I have a Mag-Hytec rear differential cover, and the level was just up to the lower level marker on the dipstick, when fully inserted.

The dealer said the correct level is just at the tip of the dipstick, when fully inserted.

Any thoughts on what the correct level of differential oil should be?



Thanks!

 

[Wingate]

Isnt there a reference plug on the back to pull out and set the level??????

 

[ata]

I don't know about the Mag-Hytec cover marks or stick levels, but on the factory cover 3/4 inch below fill plug hole COLD and at bottom of fill plug hole HOT. But a plugged vent line will make the pinion and axle (hub) seals leak.

 

[Slow Six]

Had the same problem with mine There is a reference plug in the Mag Hytec that is at the factory recommended level. I use this level and have had no more pinion seal problems.

 

[steved]

If your pinion seal is in good shape, fluid level won't affect a leak. Think about it, the pinion seal is FLOODED while you drive down the road from the fluid being whipped off the ring gear... its part of the design, not a defect. There is a lot of fluid passing across those pinion bearings to keep them cool, and they use the scavenging affect from the ring gear to get it done. There is a passage in the roof of the casting just for this purpose.



I've been running a ORU cover for the better part of 180k. I've had one pinion leak, that started about 150k. Three new seals did not help it and I was given the same "you're over filling" excuse... turns out it was in fact the YOKE that was defective and poor troubleshooting. I run my differential (11. 5AAM) overfilled by 1-1/2 inch with 85w140 and now 75w140... it hasn't leaked in the past 90k.

 

[HBarlow]

I have also used a Mag Hytec cover since day one with my '08. A friend and former Dodge dealer mechanic does all my service and repair.

He changed the differential fluid in my truck a year or so ago at 50k miles and not long afterward, after a high speed run, my truck was throwing differential fluid all over the underside of the bed, apparently out of the vent tube. He inspected it and decided he had probably overfilled it. Apparently the correct fluid level indicated on the Mag Hytec cover and the factory cover are not exactly the same. He serviced my truck again yesterday at 100k miles and changed the differential fluid again. The yolk seal never leaked after that overfill experience and is not leaking now.

We had the same Mag Hytec cover on my previous '06 and he always serviced it also. In fact, it is THE SAME cover. We removed it before I sold the '06 and installed it on my current truck. My '06 developed a yolk seal leak also that my mechanic friend replaced. I suspect some of them had bad yolk seals or seals were improperly installed.

Dealership service department so-called mechanics are often about as well trained as Wal-Mart tire and lube oil changers. Their primary goal and responsibility as well as the service writers is to sell parts and service. They'll tell us anything we're dumb enough to believe.

 

[Kirwin]

Mag-Hytec covers

I belive if you read the installation instructions for the Mag-Hytec cover, it states the the small hole in the back is for a temperature sender, and is not the fill level location. I run my 03 at the top fill line on the dipstick that they installed for some reason in the cover . I also believe that some seals weep oil more than others. The seal has a rough life under there and is subject to much dirt and temerature extremes. Some weep; some people clean their's off when they get under the truck so its weepage may not be as noticeable. My $ 0. 02 Ken Irwin

 

[Southbound]

Adding my two cents: I have used the mag hytech on three different trucks and always fill to the top line of the dip-stick and never had an issue with "over filling". I can also tell you that I have had my share of pinion seals leak (front and rear) and in every case it was a defective seal or bad yoke. Once replaced never had an issue again!!



My . 02

Southbound

 

[Blu-meanie]

I just changed mine. I installed 7½ pints, came to the second line (I think, it's been about a week so I could be wrong). I can pull it and look again if you need me to.