What is the API designation for the rear axle lube in the 06 f-350

[Fandini]

Opened the manual for my 06 f-350 single rear wheel super duty to find out the required rear axle lube for the truck only to get a ford part number. Can anybody tell me what the proper aftermarket label or API label I should be looking for for both the rear and the front axle.

 

[bushpilot]

from what i can tell the more popular choice is 75/140 royal
purple...its synthetic...just like the factory puts in the
REAR (but not the front)...and the royal purple contains the
ltd slip friction modifier (so you wont have to measure/add any).

the royal purple stuff is available at MANY retailers (including o'reillys
auto parts, pep boys, etc) for about 9.99 per quart (the ford stuff is
more than 15 bucks per quart).

Royal Purple Gear Oil

i THINK ford has modified the owners manual to recommend that you
can run the same lube in the front as the rear now....previous
years the owners manual called for lighter 75w90 in the front diff.

while youve got the cover off that 2006 why not install the 2008
alum. (wont rust) finned (for cooling) 2008 rear diff cover !?!

 

[Fandini]

So you really think a finned cover is worth the extra money. Could pick one up from four wheel parts that would add an extra quart of fluid. Or would the oem one be the better choice. Don't really want that chrome look.

 

[Fandini]

By the way, how's the weather down there in texas? A little chilly here in North Carolina.

 

[bushpilot]

ALMOST anything is better than the (non-finned) stamped steel
(and rusting) factory cover....i figured its rusting cause the paint
is getting "cooked" off...

the mag-hytec's are probably the BEST...since they add an additional
quart or more of fluid...but theyre 5 times the cost of the 2008 alum.
finned cover.

i figured (or is it justified) that for 50 bucks (w/ the longer bolts)
it was worth the improvement...and one has to wonder WHY
they went to a finned/alum. cover on the 2008's (was it just
higher towing capacity ?) or did is there some additional cooling
required ? either way it looks good and it functions better than
the rusty pos on there.

additional justification came from the "what the hell ive got the
old cover off anyway....why not..."

links to A supplier (and other mods) in my signature below.

re: texas...its COLD <to us> 30s at night, 50s during the day

 

[Fandini]

One more question I hope you or someone else can answer, what axle does the code 3L indicate. Should I post this question elsewhere in the forum.

 

[Buffs F-350]

Is it 3L 73 that would be a 3.73 gear with limited slip and go with the royel purple its good stuff .

 

[FTG-05]

ALMOST anything is better than the (non-finned) stamped steel
(and rusting) factory cover....i figured its rusting cause the paint
is getting "cooked" off...

the mag-hytec's are probably the BEST...since they add an additional
quart or more of fluid...but theyre 5 times the cost of the 2008 alum.
finned cover.

i figured (or is it justified) that for 50 bucks (w/ the longer bolts)
it was worth the improvement...and one has to wonder WHY
they went to a finned/alum. cover on the 2008's (was it just
higher towing capacity ?) or did is there some additional cooling
required ? either way it looks good and it functions better than
the rusty pos on there.

additional justification came from the "what the hell ive got the
old cover off anyway....why not..."

links to A supplier (and other mods) in my signature below.

re: texas...its COLD <to us> 30s at night, 50s during the day

Where'd you get a bigger finned cover for $50? Part number and source?

I was thinking of adding fins to my steel rear cover by welding 1"x1/8" strips to the outside - it would time consuming and I don't know how much cooler it would end up (although I would measure the temp difference with my handy dandy laser thermometer my son got me for Xmas!). I like to weld, so it might be a fun project. I'd spend $50 to not have to though.


Thanks,

Al

 

[bushpilot]

Where'd you get a bigger finned cover for $50? Part number and source?

DieselManor - Ford Sterling Differential cover