There is no reason not to use synthetic. Dino oil has zero benefits over synthetic. Don't let ignorant myth-perpetuators lead you to believe synthetic will cause leaks or any other such nonsense.

I use Mobil 1 gear oil in my diff's and change it every 35-40k or so....so every 2-3 years. Minimal cost....easy to change....why not use a high grade synthetic to reduce gear wear. Especially in the cold because it flows so much better.

__________________
-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

I had ams oils 75-90 in a dakota pickup and saw another .5 miles to the gallon on the highway on long trip. As was said an almost unnoticable gain. Im looking foward to switching my drivetrain (less engine oil) all over to ams oil. For some reason I just cant seem to go astray from my old buddy Rotella T.

Oil is cheaper than diffs. I don't see why not use synthetic from a wear reduction stand point alone.

__________________
68 280SL - 70 280SL - 70 300SEL 3.5 - 72 350SL - 72 280SEL 4.5 - 72 220 - 72 220D - 73 450SL - 84 230GE - 87 200TD - 90 190E 2.0 - 03 G500

Nissan GTR - Nissan Skyline GTS25T - Toyota GTFour - Rover Mini - Toyota Land Cruiser HJ60 - Cadillac Eldorado - BMW E30 - BMW 135i

I've got Amsoil in my trans, rear and engine. I get 28 mpg average. I use it in everything from my HD2500 to my Yanmar diesel tractors. Never let me down and I've SOLD two GM trucks in the last few years with over 250K (one with 298K) and they're both still going.

The trans oil DOUBLES the factory change interval, the rear end fluid can up to TRIPLE it. That alone is worth the price of admission. 260K and driving everyday in the SDL.

__________________
1987 SDL. The best there ever was.

I am amazed by the number of replies. I guess oil threads are always popular. I think I am gonna put regular oil in it for the following reasons:

1. I already have some.
2. There's probably regular oil in it and it's been in there for over 300k miles with no ill effect.

__________________
85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

I use Amsoil gear lube in all the vehicles I have. also use synthetic in their transmissions. the 85 300D I use their 15/40w Marine Diesel engine oil.

I started using synthetics back in 1971 on a 67 VW Bug.

Synthetics flow better when cold.and give better protection when hot. they also seem hang onto the parts when the engine has been shut down.

Charlie

__________________
there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works

Oh I forgot to ask: What size tools do I need to change the diff oil?

__________________
85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

You asked a question, then you will get some replies. that is what you wanted?

You must have made up your mind what you were going to do before posting the question.

Like chumming fish, throw out the bait, and see what comes to the surface and bites.


Charlie

__________________
there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works

I believe it is a 14MM hex.

Charlie

__________________
there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works

That sounds right Charlie.

It's a good idea to remove the filler nut before you remove the drain nut.

__________________
1987 300TD 309, xxx 2.8.2014 10,000 mile OCI


Be careful of the toes you step on today, as they may be connected to the ass you have to kiss tomorrow. anonymous

“Be who you are and say what you feel, because those who mind don’t matter, and those who matter won’t mind.” Dr. Seuss