differential fluid
 

Hi,

I have read some old threads saying that mobil1 is good and cleans well, others that say it balooned up the rubber and messed things up. I use it inthe locker on my chevy truck, and it works great. However that has a gasket that must be replaced every time the fluid is changed. My question is does the rear on a 123 car have a gasket? If so, will the mobil1 leak through, or is it such high viscosity that diffusion through any gasket would be negligible? Also, am I safe draining the fluid, putting mobil1 in and then driving it for a year? I can imagine the suspended particles will have a wearing effect, especially at high concentrations. I dont knwo the last time the fluid was changed, but I dont currently have the time to replace it twice in a short time.
Any info would be great. Thanks

JMH

The rear cover is "glued" on with sealer.

There is no gasket on the pumpkin. I just put on a thin smear of silicone sealer and bolt it up.

I don't know that the synthetic will help anything in a rear end, but hey, couldn't hoit!

The differential is actually the only place I will use a synthetic on my diesels. My opinion only, but I'm not going to use synthetic ATF or motor oil. But for the differential I do like Mobil 1 gear oil.

Although the differential cover is sealed with "gasket-in-a-tube" liquid sealer, there are still conventional rubber seals for the half-axle shafts and the pinion seal that could possibly have a problem. Haven't had any problems myself. And the differential is quieter too.

Ken300D

I am curious as to why you don't use synthetics in the engine, trans.
Cost?

First of all you can understand this is a matter of opinion.

Cost is a factor. I believe the oil needs to be changed often in a diesel due to the soot that gets thrown into the oil by the diesel combustion process. I can understand how a synthetic provides superior lubrication, however I think "oil change" is more important than "many miles between changes" as in a synthetic.

A similar line of thought for the transmission. Dirt wears out a transmission far faster than anything else. So change the fluid and filter regularly, at least once a year.

But I do get some synthetic properties from the oil additive I use with every change - STP Oil Treatment. Now there's a controversial topic. :)

Ken300D

I use synthetic everywhere I can. Mobil Delvac-1 in the engine. Mobil synthetic ATF in the transmission. Redline synthetic in the differential (just changed this one yesterday). I hope my MB (and all my other vehicles, except the toyota camry) last forever. The cost for synthetic over standard oil isnt that much of an increase when I look at the cost of maintianing my current vehicles or the car payment on a new one. Synthetic doesnt add that much to that number, so I go synthetic.