Went down to the dealer today to get a alli spin on filter and some diff lube. Guy tells me diff lube is $21.68 a quart.....Ouch! I ask him about Mobil and if that will work. He tells me it doesn't meet GM specs. What are you guys using and how much are you paying?


Thanks


Rich.

Well I got Mobil 1 in my rear diff.........almost 8 quarts with the Mag Hytec cover........


So buy the MOBIL 1 or even Valvoline Synthetic with a GL5 rating and the right viscosity and be done with it.


I got 12/qt. bottles for about $80.00 locally with sales tax.





Thttp://www.dieselplace.com/forum/smileys/Clown.gifNYEdited by: GMC-2002-Dmax

There's something of a controversy over the GM spec for the rear differential lube.


The GL-5 rating Tony mentions should be good enough and I believe the axle manufacturer says it's okay, but GM's come up with their own spec.


I've not been able to ascertain whether or not any of the GL-5 rated lubricants will meet that. The possible problem just showed up here in some recent posts. I'd say if your SM and the dealership are good folks, you shouldn't have a problem. But if you've got a b*tthead SM like I have, you may be better off biting the bullet unless someone here can show data that the Mobil or one of the others meets the GM spec...http://www.dieselplace.com/forum/smileys/Ermm.gif


I've been putting off the first change hoping for some more info, but I've got to get it changed pretty quick and right now it looks like it's going to be the GM stuff. I don't like that idea, but I can't risk a possible problem should some sort of difficulty arise with the locker.

I used the Valvoline synthetic and my dealer thought that was okay. I did everything myself and was very simple.


Benhttp://www.dieselplace.com/forum/smileys/Rock On.gif

I can't say for sure, but i believe RP and Mobil and similar meet the specs. for the diffs.


Befor I changed my oil in the rear end at around 1500 miles I had a leak on the front seal and they repaird it. After the oil change I have not had any problems.


I had to buy some of the outragiously priced GM oil for my Denali to put in the transfer case. I am not sure if it is the same GL-5 or not. Roughly $100 for about 3 quarts. This oil apparently has some added friction to grip the clutches in the transfer case and no other oil company makes anything to meet it. I believe this is the only oil that the other manufactures can not meet.

I can't say for sure, but i believe RP and Mobil and similar meet the specs. for the diffs.


Befor I changed my oil in the rear end at around 1500 miles I had a leak on the front seal and they repaird it. After the oil change I have not had any problems.


I had to buy some of the outragiously priced GM oil for my Denali to put in the transfer case. I am not sure if it is the same GL-5 or not. Roughly $100 for about 3 quarts. This oil apparently has some added friction to grip the clutches in the transfer case and no other oil company makes anything to meet it. I believe this is the only oil that the other manufactures can not meet.

Somebody makes that oil for GM and with a a little searching you might find a cheaper source because you know GM is going to mark it up 200 to 300% or more at dealers.

I've had Royel Purple 75-140 in my truck for 50K with no problems. I would use Mobile, RP, Red Line, Amsoil or what ever synthetic you like and I doubt you will have any problems.

I used Royal Purple 75w-90 in mine +/- 18,000 miles ago. No problems, so far. It wasn't "grape juice", but it was purple ! http://www.dieselplace.com/forum/smileys/Big Smile.gif

Somebody makes that oil for GM and with a a little searching you might find a cheaper source because you know GM is going to mark it up 200 to 300% or more at dealers.


IIRC, someone chased it down to Texaco, got some correspondence back from them saying it was a product produced for GM and not available to anyone else.

So let me get this straight, Texaco makes the oil for GM but we can't buy it. What's the deal. Anybody know the PN for the texaco oil.

Schaeffer's 741 75w-90 Full Synthetic. Meets Eaton specs and the GL5 rating according to their web page www.schaefferoil.com (http://www.schaefferoil.com) I have used nothing but Schaeffer's lubes, oil, and additives in my truck and am very pleased with their performance. Only draw back to this lube is that the smallest available quantity is 5 gallons ($120.00 at my local dealer, $6.00 a quart if my math is correct) Edited by: HOOKEM

I chased my tail round and round on this, and it always comes back to nothing else meeting GM's spec. I know others use products such as Mobil 1, and its probably okay. If you're the type to go by the book (GM's spec), you gotta use the Grape Juice. I bought mine from Eric.

FWIW, I used Redline 75W90 synthetic in my rear diff (8 quarts with Mag-Hytec cover). I've noticed that my shifts feel a bit firmer--not rough, but definitely more "crisp" than before. I suppose the friction coefficient with the Redline is a bit different than OEM fluid. Working perfectly, no leaks, planning to do the front soon.


~Terel

I don't see how putting a different oil in the rear would change your shifting.


I believe the only benifit for putting good oil in the rear would be for heat.

My dealer uses Mobil 1 in their shop so it must be OK. They are a large truck dealership use it in all diff. work.

FWIW, I used Redline 75W90 synthetic in my rear diff (8 quarts with Mag-Hytec cover). I've noticed that my shifts feel a bit firmer--not rough, but definitely more "crisp" than before. I suppose the friction coefficient with the Redline is a bit different than OEM fluid. Working perfectly, no leaks, planning to do the front soon.


~Terel

The shift is a fluke and not related to diff oil unless the oil before you changed it was really nasty and long overdue a change. And on the extended covers for diffs that add oil capacity. We got by for many years without them and I think ot is more hype than anything to provide someone a source of income. There is very little airflow behind pig from suction and with big cover I wonder how well it would oil ad cool pinion bearing on a steep climb.

I don't see how putting a different oil in the rear would change your shifting.


I believe the only benifit for putting good oil in the rear would be for heat.





Well, I can't be sure, but I would imagine each lube has a different formula, a component of which is friction modifiers (for limited slip vs. non-limited slip differentials). I'm pretty in tune with how my truck is running/riding, and it feels like the shifts are more "positive" than they used to be. Maybe I'm imagining it, though.


~Terel


Where's the cheapest place folks have found Mobile 1 synthetic lube?

If you think the Mag-Hytec cover doesn't do any thing just tow something and compare the temps of a standard cover with the Mag. You will find there is alot of difference in the temps and just having twice the amount of oil is a great benefit. But hey that's just my opinion. As for feeling a shift difference with different oil in the diff's you must have a very sensetive a$$.http://www.dieselplace.com/forum/smileys/Big Smile.gif

Blue Max,


Are you coming on to me? http://www.dieselplace.com/forum/smileys/HiHi.gif


Maybe I'm imagining it. For those of you who take temp readings off your rear diffs--do you simply buy a tranny temp gauge, or does someone make a temp gauge specifically for rear diffs?


~Terel

Hey I'm a Chevy driver not a Dodge man.http://www.dieselplace.com/forum/smileys/HiHi.gif I think most use a tranny temp gauge and sender.http://www.dieselplace.com/forum/smileys/Cool.gif

Auto-Meter makes a diff gage.


http://hp.autometer.com/products/sport_comp/electric_gauges/electric_gauges.html


http://hp.autometer.com/products/ultra_lite/electric_gauges/electric_gauges.html


Just two examples, I'm sure there are other lines that include the diff temp as well.


DennisEdited by: baimpala

If you think the Mag-Hytec cover doesn't do any thing just tow something and compare the temps of a standard cover with the Mag. You will find there is alot of difference in the temps and just having twice the amount of oil is a great benefit. But hey that's just my opinion. As for feeling a shift difference with different oil in the diff's you must have a very sensetive a$$.http://www.dieselplace.com/forum/smileys/Big Smile.gif

I have towed for over 30 year and some very nasty loads too and I have never had a rear end failure yet with a stock 10.5, D60, D44 a 12 bolt or 9.5 semi floater. (never been to impressed with the 10 bolt) How did I ever survive without them? Like I said, more than anything it is a source of income for the guy that makes them as he has convinced some people that they cannot get by without one. Whats next? Wheel bearing coolers or will it be tranfercase coolers for those that want to do 60 in low range for long periods of time. http://www.dieselplace.com/forum/smileys/HiHi.gif Edited by: snoman

To each his own, but my last truck got the rear end hot enough to burn and peel the paint on the rear diff cover.http://www.dieselplace.com/forum/smileys/Cry.gif

It's somewhat funny to me about new trucks and there owners. Don't get me wrong, I am the owner of a new CC, D/A and love the truck very much.


Some of the "gadgets", ie aftermarket add-ons, probably actually do what they claim, but are probably not really necessary, but some do add a degree of safety. People that I have grown up with have used 1/2 ton Fords, Chevy's and even a few dodges to pull trailer after trailer with loads of peanuts, corn, cotton, hay, water trailers, fuel trailers, tractors, doziers, feed, seed, chemicals, etc. Why yes many probably were overloaded but none the less they have stood the test of time. My father currently drives a truck that he bought new over 25 years ago, and has over 400,000 miles on the original 454. The motor has never so much as had the carb off of it. I should mention that he generally changes the oil once a year.


When commenting on what my new 2500hd is "Rated" to pull, he laughed and said his 1/2 ton would pull more than that...


Well my .02 cents says dont take money from your family's mouth to feed your truck, but have fun, stimulate our economy, and by God, if you can feel the difference with new diff fluid, who is to say that you didnt!


http://www.dieselplace.com/forum/smileys/HiHi.gif

If you think the Mag-Hytec cover doesn't do any thing just tow something and compare the temps of a standard cover with the Mag. You will find there is alot of difference in the temps and just having twice the amount of oil is a great benefit. But hey that's just my opinion. As for feeling a shift difference with different oil in the diff's you must have a very sensetive a$$.http://www.dieselplace.com/forum/smileys/Big Smile.gif

I have towed for over 30 year and some very nasty loads too and I have never had a rear end failure yet with a stock 10.5, D60, D44 a 12 bolt or 9.5 semi floater. (never been to impressed with the 10 bolt) How did I ever survive without them? Like I said, more than anything it is a source of income for the guy that makes them as he has convinced some people that they cannot get by without one. Whats next? Wheel bearing coolers or will it be tranfercase coolers for those that want to do 60 in low range for long periods of time. http://www.dieselplace.com/forum/smileys/HiHi.gif


Hey snoman,


Can have that pattent. That sounds like the next big thing for these guys running these big 24" wheels or spinners.

Hey snoman,


Can have that pattent. That sounds like the next big thing for these guys running these big 24" wheels or spinners.





I live at the beach and you would be suprised at how many one tons that you see with chromed 24"-26" wheels. Many are kids that look like they might be 18 years old driving them....And to think that I complained about buying tires for 16" wheels...lol


I saw a Tonka Yellow F450 Monday that had chromed 24" wheels. This was a local landscapers truck. You know that his clients love to have that truck parked in their yard...

Well I did it. Went down to the dealer today and baught 4 qts. Was told I'd need just over 3. I guess what it boiled down to for me was piece of mind. I'd hate to be half way up Donner summit thinking if my rear end was baking itself. Not to mention taking away the ability for a SM to have an excuse not to warranty the rear end. I'm sure the other oils are fine but in my mind GM probably had a reason to spec out they're own stuff. They don't really do it with engine oil, radiator fluid, or most of the filters.


Just my .02


Rich.

You could allways get some SPF 40 and put it on your rear.http://www.dieselplace.com/forum/smileys/HiHi.gif

It's somewhat funny to me about new trucks and there owners. Don't get me wrong, I am the owner of a new CC, D/A and love the truck very much.


Some of the "gadgets", ie aftermarket add-ons, probably actually do what they claim, but are probably not really necessary, but some do add a degree of safety. People that I have grown up with have used 1/2 ton Fords, Chevy's and even a few dodges to pull trailer after trailer with loads of peanuts, corn, cotton, hay, water trailers, fuel trailers, tractors, doziers, feed, seed, chemicals, etc. Why yes many probably were overloaded but none the less they have stood the test of time. My father currently drives a truck that he bought new over 25 years ago, and has over 400,000 miles on the original 454. The motor has never so much as had the carb off of it. I should mention that he generally changes the oil once a year.


When commenting on what my new 2500hd is "Rated" to pull, he laughed and said his 1/2 ton would pull more than that...


Well my .02 cents says dont take money from your family's mouth to feed your truck, but have fun, stimulate our economy, and by God, if you can feel the difference with new diff fluid, who is to say that you didnt!


http://www.dieselplace.com/forum/smileys/HiHi.gif

There is a lot of truth to this. Modern truck may have big engines and such but they are more car than truck and the old family lead sled sedans and wagon or the late 60's could pull as much weight or more than most of the modern trucks out there today. Even the old Chevy, Olds and Pntiac lead sleds had stronger rear ends and trannies than GM puts in a modern 4x4 1/2 ton pick up.