Whch rear end lube?

[mwillis]

We have a 2002 Chev. 3500 D/A. We pull a 14000# 5er. I have read in the threads of 2 rear end lubes for the 3500, 12378261 and 12346140. I ask GM which one to use and they said to see my dealer. The dealer dosen't know either, so I came here to ask the experts. Are they both synthetic, and which one should we be using? We will be pulling approx. 1/2 the time and the rest solo. Thanks

[mackin]

All the info you need or what is here,
-->>>>>>>>http://forum.62-65-dieselpage.com/cgi-bin/ultimatebb.cgi?ubb=get_topic&f=3&t=001361&p=


I guess it's your decision to go GM or not. I run Amsoil 75w 90 synthetic in mine. Yours like mine came standard with the Eaton locker. Check your window sticker just in case. Unless your ordered yours then you know..... No additive is needed. Good luck.
MAC :D :D

[Edmac]

mwillis:
You may want to read this thread also:
http://forum.62-65-dieselpage.com/ubb/ultimatebb.php?ubb=get_topic&f=7&t=002814
Ed

[Kanuck]

The recommended rear axle fluid is P/N 12378557
for a 9.75 and P/N 12378261 for all others. The
P/N 12378261 is SAE 75W-90 Synthetic. The 9.75,I believe,is the steering rear axle.

[mwillis]

Thanks guys for the quick response. According to previous threads, rear end lube #12378261 is a synthetic 75W90. And 12346140 is 75W140. My question: Is the 12346140 a synthetic and is it good for heavy hauling? Thanks again

[LanduytG]

Don't give the dealer the big price for their stuff. Just use the Amsoil Series 2000 75W-90 and thats all you will need.
Greg

[ 04-08-2002: Message edited by: LanduytG ]</p>

[george morrison]

The Mobil 1 75W-90 synthetic is fine also. Get it at your local Pep Boys/Autozone, etc. It already has the limited slip additive in it, ready to go. It is the same gear oil used in just about every over the road rig. A one time change out.
George Morrison, STLE CLS

[gdblake]

This probably been addressed before--but I can't find it in the 6 pages I've reviewed. Can someone please tell me how much rear end fluid is required to refill the rear end after draining? HD 3.73LS. Any additives required for the limited slip? Thank you.

[3176CATPOWER]

A previous post said 4 quarts on the refill.

[gdblake]

Thank you, 3176CATPOWER !!

[csimo]

Use ANY 75w90 GL-5 rated SYNTHETIC gear lube you like. If you tow heavy very often use 75w140 GL-5 rated SYNTHETIC.

I wouldn't use the 75w140 in the winter if it gets too cold in your area.

NO ADDITIVE is required for ANY axle on the HD's.

[ 04-20-2002: Message edited by: csimo ]</p>

[thechevyhdman]

my rear end I dont know whats the rpo number for it, But its the 11.5 inch ring gear AAM axle, in a dmax took 4.75 quarts.

[DmaxMaverick]

thechevyhdman

All rear ends on the HD's with the 11.5" require the same lube. Synthetic GL-5. 75w-90 for normal use, 75w-140 for heavy towing.

[56Nomad]

george morrison wrote:

&lt;&lt;The Mobil 1 75W-90 synthetic is fine also. Get it at your
local Pep Boys/Autozone, etc. It already has the limited slip
additive in it, ready to go. It is the same gear oil used in just
about every over the road rig. A one time change out.&gt;&gt;

I searched and read all the previous posts when it was time to do my
first rear end oil change. Based on the information that the "experts"
from this forum provided, I also decided to go with Mobil 1.

It was much more reasonable in cost than what the dealer wanted!
Autozone and Kragen carry it.

[White Knight]

Just changed my rear end fluid this afternoon at about 6500 miles. Dealer did the first change at about 2000 miles. Just completed my first tow (2500 miles), so I thought it was time for another change. Used Mobil 1 from Auto Zone. Used a piece of plastic tubing and slipped it over the nozzle on the lube bottle and just squirted it into the rear end. I held the lube bottle up over the spare tire. Worked great. Four quarts filled it to where it was just starting to run out the fill hole.

Sure much cheaper to do it yourself than have the dealer do it. While I was at it I changed the oil and filter. Also changed the transmission filter. I figure my two hour project would have cost about $350 at the dealer.