Rear axle ID

**BroncoHauler** · 02-20-2011, 07:43 PM

So, I'm planning on an Amsoil engine oil & filter change, Amsoil front diff fluid change, and Amsoil rear diff fluid change. Know what I need for the engine, filters, front diff, but in trying to figure out what fluid I need for the rear diff, I looked in the Ford owners manual and see many Ford rear axle options, a number of which require different diff fluids.

How can I tell which rear axle I have? I know it's not an aftermarket Dynatrac, but is there a Dyna or some other axle tag on it that I should look for? I took a real quick look without crawling under the van and didn't see anything, but if there's a number I should look for do you know where it is? FWIW, I looked on the original factory Ford window sticker and didn't see anything other than having the 4.10 gears.

Herb

**daveb** · 02-20-2011, 07:57 PM

All I know is what SMB uses on my limited slip:
AMSOIL Severe Gear SAE 75W-140 synthetic but they also have to put in the anti chatter stuff or going around a corner does some clutch type binding.
[edit] not sure if that's the front or rear...front is a air locker. I'm just looking at the bottle left over.

Roonie · 02-20-2011, 08:08 PM

Just curious no where in my SMB 4x4 conversion info does it mention changing the rear diff fluid. It isn't even mentioned on their service and maintenance schedule? Only the front differential fluid is listed and recommended. Any reason for this?

**daveb** · 02-20-2011, 09:16 PM

I was told about the correct break in procedures and also had both front and rear differential fluids replaced before what’s normally recommended by Ford. It's the limited slip additive that has given me some trouble. Same thing happened with my Impala SS. Chevy didn’t add enough, if at all.

**BroncoHauler** · 02-20-2011, 10:47 PM

Yeah, don't think I even have a limited slip. I'll re-check the Ford window sticker, but I don't recall seeing mention of a LS.

Herb

carringb · 02-20-2011, 11:41 PM

I use 75w150 full synthetic. Mine is the Dana70 but this should be used in the Dana60 also.

I also have to add 2 bottles of Limited Slip additive, or I get chatter and can't even turn under full throttle (not OEM LS.... With OEM LS I'd try w/out first and only add if you get chatter).

scatter · 02-21-2011, 08:38 AM

Herb, if you have the Ford differential, there should be a little ID plate held down by two of the rear cover plate bolts. It will tell you all about what you have in there. Also, the ID sticker on your front door jamb should have most of the info too, but the rear end tag is the final say.
If you do have a limited slip (I bet you do) then don't forget the additive. It IS needed. There're several posts here on how to determine if your differential is open or limited slip. When filling, just fill to the bottom of the filler plug. THIS IS FOR FORD UNITS ONLY! With a Dynatrac just use the amount they say. If you fill that one to the bottom of the plug, you will puke out fluid and make a real mess.

Roonie · 02-21-2011, 12:56 PM

Quote:

Originally Posted by Roonie

Just curious no where in my SMB 4x4 conversion info does it mention changing the rear diff fluid. It isn't even mentioned on their service and maintenance schedule? Only the front differential fluid is listed and recommended. Any reason for this?

Found it in my owners manual.... recommended 50k and 100k replace rear axle lube for Class A motorhomes and for the F450/550.

Quote:

Originally Posted by BroncoHauler

Yeah, don't think I even have a limited slip. I'll re-check the Ford window sticker, but I don't recall seeing mention of a LS.
Herb

on my window sticker it says in one line 4.10 ratio limited slip axle

Any one have a definitive answer on how much additive to add with the oil with the factory LS from Ford?

**BroncoHauler** · 02-21-2011, 01:41 PM

My rear axle tag:

4.10V C24-FA
2002708-6L-S

Double-checking my windowsticker, I do have 4.10 with limited slip.

Now, looking at the van owner's manual, seems the E-350 possibilities are:

SAE 75W-140 synthetic rear axle lubricant (with friction modifier)
1) Dana M70 (M248) E-350 conventional and Limited Slip; 6.3 pints

SAE 90 Hypoid gear oil (with friction modifier)
Dana Limited Slip axles
1) M60 (M248) E250/350; 6.3 pints
2) M70FF (M267FF) E-350; 6.8 pints

OK, the quantity issue doesn't concern me given that according to the manual, you fill Dana rear axles to 1/4" to 9/16" below the bottom of the fill hole so there's really no difference in how much I have to buy, but I need to figure out whether to buy the Amsoil equivalent of the 75W-140 or the 90 Hypoid oil.

FWIW, the Ford owner's manual specifies 8oz of Aditive Friction Modifier XL-3 or equivalent meeting Ford specification EST-M2C118-A.

Any ideas on how to decode the rear axle tag and figure out my rear axle and the corresponding lubricant? This is for an '06 E-350 van.

Herb

Roonie · 02-21-2011, 02:00 PM

Here is a good resource I found on the Dana 60
http://www.pirate4x4.com/tech/billavista/60_front/