Rear Diff Fluid

[idiabuse]

AMSOIL gear oil is lifetime fill on most cars/trucks
With over the road Semi trucks the 75W90 has a
250,000 mile drain interval.
Fuel milage will also improve with the slick stuff
From AMSOIL
at $12.35 a quart retail price it very affordable.


Javier

 

[gonecrazyi]

Also, not all 4.10 rears are limited slip. I've got several that arnt.

 

[SLC97SR5]

No limited slip here either.

I used Valvoline Synthetic 75-140w. The manual calls for synthetic at 100k intervals. I bought 4 quarts.

 

[idi traveler]

My tag just says 4.10, no ls on it.

 

[Sw1tchfoot]

Everyone rants and raves about Royal Purple but it looked like is performed very poorly in a test of multiple gear oils, the test was performed by Amsoil though. Both the Mobil 1 and (obviously) the Amsoil performed well in their tests.

I can't find the link.

 

[Rot Box]

I on run a 90 grade oil (LE-607 from Lubrication engineers... no longer made but I have a large supply).

LE is good stuff I believe LE just switched the name from 607 to 1607 last I checked anyway. It would be a shame if they stopped making that grade altogether.

 

[FORDF250HDXLT]

Everyone rants and raves about Royal Purple but it looked like is performed very poorly in a test of multiple gear oils, the test was performed by Amsoil though. Both the Mobil 1 and (obviously) the Amsoil performed well in their tests.

I can't find the link.

http://www.synthetic-oil-tech.com/Gear Lube White Paper.pdf

 

[phazertwo]

Another 4:10 here with no limited slip. Wish it was though!

PZ

 

[PwrSmoke]

i don't tow with my truck and if i ever did it is not heavy. i just daily drive it.

so based on my use you would say the 75W90 synth?

Yep, that will give you very low rolling resistance to help MPG and it will be cold friendly and last a long interval (60K minimum)

 

[RLDSL]

If you use the Amsoil Severe GEar, you should not need additive. They make one for the extremely rare instance where you might experience chattering still with the synthetic, but I have yet to run across a need for it in over 30 years. The synthetic is just plain slick, and you don't want to make it too darn slick or you will defeat the purpose of your clutch packs.

 

[RLDSL]

AMSOIL gear oil is lifetime fill on most cars/trucks
With over the road Semi trucks the 75W90 has a
250,000 mile drain interval.
Fuel milage will also improve with the slick stuff
From AMSOIL
at $12.35 a quart retail price it very affordable.


Javier

That's a little misleading. Drain interval for our trucks is between 50-100k ( 50k for severe service which would include those of us who do heavy towing or spend a lot of time on dirt roads ) Big truck axles are built with a bit more overkill and have a higher drain interval on dino oil to begin with

 

[PwrSmoke]

That's a little misleading. Drain interval for our trucks is between 50-100k ( 50k for severe service which would include those of us who do heavy towing or spend a lot of time on dirt roads ) Big truck axles are built with a bit more overkill and have a higher drain interval on dino oil to begin with

I agree. I base my intervals on a combination of operational situations and running oil temp. Here's something from 2005 that rounds up the axle oil temps on my truck.

http://www.fourwheeler.com/techarticles/drivetrain/129_0607_1986_ford_f250_hd_towing_axle/viewall.html

 

[bghnkinf350]

I have been on the fence about running the stuff - I guess now might be the time to give it a shot!

 

[OnDaRoad]

Real Feedback ....

Real feedback by a real guy who uses his F350 to actually
work - towing every day in all possible conditions ....

Royal Purple 85/140 which you can order in at O'Reilly's or most other chain parts stores .....

85/140 because the heavier weight provides additional
' cushioning ' for your rear ...


Nothing better - my million mile testimonial ...

Most rear diffs fail because the fluid either falls below
the level where it can lube or because it never gets changed

FIRST THING ...

Check your breather vent that the rear brake hose is
part of on the driver rear - pulll the hose and see if the
breather is clogged up (usually is) - clean it carefully
and then make sure your breather hose is in good shape - check the
breather cap - make sure it is above the rear diff and fastened
to the driver side frame rail ....


Servicing your dif for the first time ?

Jack up the front or park on an incline ...
Remove the cover carefully .......

The reason I say that - if you have the original bolts
they likely will twist off during removal if you are not
careful - leaving you the arduous task of extracting bolts

If you can, have the rear axle on jackstands and your
tranny in neutral (you should preferably have the truck
on a lift but for most guys that is not an option)

Spray brake cleaner and clean the ring & pinion
completely - use lots of paper towels to mop up
the drainage at the bottom of the diff casting

If you are at an incline - this helps to drain

Be sure you clean all the brake fluid out

Turn the rear end as you clean to get the whole gear

Replace the bolts with new ones ..

Check your diff cover for warping, straighten
it with a block of wood & hammer on a flat
surface

Some guys use no gasket - just silicone

I prefer a paper gasket with gray RTV

I tack the gasket to the cover with a thin film
to hold it ....

Carefully install the cover - torque carefully to
insure a tight ft but not too tight to warp the cover

On a 4:10 with a factory cover - allow just
under 4 quarts to refill - some guys overfill

I don't ....



Jim

 

[itsacrazyasian]

Real feedback by a real guy who uses his F350 to actually
work - towing every day in all possible conditions ....

Royal Purple 85/140 which you can order in at O'Reilly's or most other chain parts stores .....

85/140 because the heavier weight provides additional
' cushioning ' for your rear ...


Nothing better - my million mile testimonial ...

Most rear diffs fail because the fluid either falls below
the level where it can lube or because it never gets changed

FIRST THING ...

Check your breather vent that the rear brake hose is
part of on the driver rear - pulll the hose and see if the
breather is clogged up (usually is) - clean it carefully
and then make sure your breather hose is in good shape - check the
breather cap - make sure it is above the rear diff and fastened
to the driver side frame rail ....


Servicing your dif for the first time ?

Jack up the front or park on an incline ...
Remove the cover carefully .......

The reason I say that - if you have the original bolts
they likely will twist off during removal if you are not
careful - leaving you the arduous task of extracting bolts

If you can, have the rear axle on jackstands and your
tranny in neutral (you should preferably have the truck
on a lift but for most guys that is not an option)

Spray brake cleaner and clean the ring & pinion
completely - use lots of paper towels to mop up
the drainage at the bottom of the diff casting

If you are at an incline - this helps to drain

Be sure you clean all the brake fluid out

Turn the rear end as you clean to get the whole gear

Replace the bolts with new ones ..

Check your diff cover for warping, straighten
it with a block of wood & hammer on a flat
surface

Some guys use no gasket - just silicone

I prefer a paper gasket with gray RTV

I tack the gasket to the cover with a thin film
to hold it ....

Carefully install the cover - torque carefully to
insure a tight ft but not too tight to warp the cover

On a 4:10 with a factory cover - allow just
under 4 quarts to refill - some guys overfill

I don't ....



Jim

Just to add to the fire. I run amsoil in the limo fleet. Everything gets 75w140. The Town Cars are drained and filled right at 60K. I don't touch them again. once in a blue moon i change a axle bearing/axle. The E350's i change at 100K and don't touch them again except for top offs in rare instances a seal may leak. the vans get an easy 200K out of the amsoil fluid and it stays very clean.