Differential "friction additive" question

tortorelli · 08-09-2009, 10:20 AM

I recently bought a 2000 SMB E-350 Super Duty with a Dana rear diff. (42 799 2) Wondering if this is a conventional or limited-slip differential and if I should put the "friction modifier additive" in with the standard 80-90W gear oil??? Also, which fluid should I put in the transfer case? Auto tranny says Mercon. Should I use this in the transfer case as well? Thanks alot. Sucks to not have the manuals.

Ford_6L_E350 · 08-09-2009, 11:04 AM

You can go to www.ford.com and look under 'Owner Services'. Select the 'Maintenance Schedule' and enter your VIN and some more information and you can get a complete list of services.

Mike

SMBDAD · 08-09-2009, 11:24 AM

I just did both diff's. I used royal purple synthetic. It did not need additional modifier. I liked having the synthetic, as the rear bearings are lubed by the gear oil (full floating). It has been smooth.

LeadDoggy · 08-09-2009, 07:07 PM

How to test differential
block wheels so vehicle won't roll
jack up one rear wheel
with trans in neutral and parking brake off try to turn the wheel.
if it turns, you have an open differential and if it does not trun you probally have a limited slip.

Quote:

Originally Posted by tortorelli

I recently bought a 2000 SMB E-350 Super Duty with a Dana rear diff. (42 799 2) Wondering if this is a conventional or limited-slip differential and if I should put the "friction modifier additive" in with the standard 80-90W gear oil??? Also, which fluid should I put in the transfer case? Auto tranny says Mercon. Should I use this in the transfer case as well? Thanks alot. Sucks to not have the manuals.

spurious · 08-09-2009, 08:47 PM

If it has the original diff in it look under the "Axel" on the white tag on the drivers door. Generally speaking if it is two numbers "24" it is NOT a limited slip diff. If there is a letter preceeding the number "B24" it IS a limited slip diff. Quick reference prior to jacking the van up. You can also reference that code to tell what gears were in it from factory. good luck!

SMBDAD · 08-09-2009, 08:56 PM

I forgot about the transfer case. If you have a borg-warner (like I do), you should be putting ATF in it not gear oil. I used synthetic mobil 1.

tortorelli · 08-09-2009, 10:16 PM

Thanks a lot for the input!! SMBDAD, I do have a borg-warner transfer case. So mercon is fine when I service it?

SMBDAD · 08-09-2009, 10:33 PM

[ SMBDAD, I do have a borg-warner transfer case. So mercon is fine when I service it?[/quote]

I did not ask him wich ATF he recommended. When he said ATF I stated that I was putting syn Mobil 1 in the tranny so I was going to use it in the transfer case as well. He was old school and did not think it was necessary to go with synthetic, but the case only hold about 2quarts so why not!