My salesman assured me that all fluids were checked on my truck before I took delivery. Well, I decided to check the rear end fluid today. Guess what? It is way low. I can barley feel any fluid with my pinky. I have about 1300 miles on the truck and was wondering if this will hurt it at all?http://www.dieselplace.com/forum/smileys/Dead.gif

The lubricant level should be between 0-10 mm (0-0.4 in). Any lower you need to have them add some.

Oh well nevermind then, I am used to the level having to be right up to the plug. Thank youEdited by: Mr. Mister

Mr. Mister.


Be careful, I think there's a "ledge" just inside the hole. You may be getting the gear oil from the ledge on your pinky. I stuck a curved aluminum air blowgun tube farther in and was able to tell that it was quite a bit lower than from the pinky test.


I talked to may salesman prior to deliver and asked him twice to have it checked. When I talked to him at delivery time, he said it was checked and fine. Before I put a socket on the bolt, I noticed that it had absolutely no marks. After I put a socket on it, you could notice some paint discolorations if you looked closely. Needless to say... they didn't do it. I went back and raised hell.

I think we need to be careful about the lubricant level. I think lub level to the fill plug is when the axle bearing are lubricated by the diffrencial lub, if not then it could be @ 0-10 mm (0-0.4in)..


The lubricant level should be between 0-10 mm (0-0.4 in). Any lower you need to have them add some.

1300 miles? Did you not change the fluid at 500 miles?

I haven't towed with it at all, so it's not suggested to change it until 5000.

Read about this issue befor picking our truck up. I removed the rear end fill plug at home, pinky checked, & pulled no fluid. Discussed this with the service manager next day and he pulled up an inspection bulletin on the 2004K Sierra 4WD Rear Drive Axle 8.6 inch. "Document ID # 860218" seems to indicate the level should be 0.6 to 1.6 inches below the fill plug openning. Problem was he couldn't find one for the Eaton (11.5 inch?). Says it is the same deal, no longer gets filled to pinky level due to the venting. Anyway, that's his story. Still not sure what to make of it.

Make of it what you will, but nothing beats measurement. Go ahead and drain the fluid and measure what comes out. In my case it was 2 1/2 quarts of factory grape juice. The specification is for 4 quarts. When you fill it with 4 quarts it is up to the vent hole. Draw your own conclusions from what this servce manager told you.


Some people might say those are blatant lies!

Well according to the techs here, the GM rated capacity of the Eaton is 3 3/4 qts. give or take a few hundreths of a quart. That is about 1/2 inch below the fill hole according to them, so 4 qts should bring it to the hole or very near it.


Most folks still do what I was taught a long time ago, fill it to the hole.


After being assured that mine had been checked, there were no wrench marks on the rear fill plug when I checked it, and it was about 1 1/2 inches below the fill hole. While it's more difficult to check since your finger won't go into the hole, the front differential on my truck was low as well.


When I confronted him, since it was he who told my salesman they were okay, my new Service Manager was un-apologetic nor willing to admit they weren't checked or could be low. He and I are not on very good terms now, but the rear and front differentials on my truck are now full....


Guess it's better to find out you need a new dealership before some sort of possibly serious problem, than while it's in his shop.

I think that 4 quarts of fluild is a clean dry measurement and if you install 4 quarts into a dry housing by the time the fluild make it though the tube to the inner & outter bearings on both sides that your readings our going to show low. So like 2fast2 said he only got 2 1/2 quarts do you think that 3/4's of a quart in each side would be in the axle tube, bearings, axle hub and side carrier bearings ????? Now does heat build pressure? Heated oil expands and you if keep it under 50 MPH and only for short burst runs do you think it will do damage? I say no!!!! If they put 5 1/2 quarts in at the factory do you think it might heat up and expand and come out the vent tube? I say maybe not sure, but that could happen. That is the idea of breaking in, Heat up expand and cool down. NOT OVER HEAT .I would change the rear fluild at 500 miles and refill 1/2 from the fill plug. We all can fit our pinkies in that far ( first knuckle) that should be more then enough. That is how I feel so I am not going to worry about that until I get to 500 miles. I say drive and enjoy cause that is what I'm going to do. This forum is great and you get a lot of great information on here but sometimes to much information is no good. I have only heard of one person having rear end trouble so far and I have heard of many people driving 5000 miles or even more with no trouble. Think about it Edited by: Leatherman

Installed Mag-hytec cover, took 8 quarts to get it to the correct mark. First change at 40K miles, original gear lube was dark but not bad enough to make me lose sleep. New cover has a dipstick and you don't have to screw with sticking your finger in any holes to check. Now you can pour in gear lube from the top. Great design!

just remember the dipstick is magnetic and can pick up allan wrenches that end up in the cover..he he he he.......alwasy have a clean bucket to redrain the new fluid if you get an allen wrench in the cover......

Where can I get some "factory" or other "official" instructions on how to check and change my rear end oil?


Thanks!


Don

Don, it is one of the easiest DIY projects you'll ever do on your truck. At the bottom of the differential is a drain plug that accepts a square drive from a ratchet (can't recall if it is 3/8 drive or 1/2 inch, I think 3/8). The check / fill plug is on the side of the differential, lower than 1/2 was up. Can't miss it. Remove the check / fill plug, then remove your drain plug and let all the messy goop drain out. You'll most likely find you have around 2 quarts from the factory, it is one of the common ways you get "shorted" (i.e. made love to) by the general. Replace the drain plug and add 4 quarts of your fluid of choice (GM grape juice or Mobil 1 75-90 are two of the favorites) and replace the fill plug. It will likely start to overflow as you get to the middle to end of the 4th quart so be ready to catch drips. Wipe everything clean after you replace the fill plug, so you can tell if you have a leak in the future. Drive on.


Good luck,


Jim

Thanks 2fast! I think I'll try to get it done before this weekend's trip!

Installed Mag-hytec cover, took 8 quarts to get it to the correct mark. First change at 40K miles, original gear lube was dark but not bad enough to make me lose sleep. New cover has a dipstick and you don't have to screw with sticking your finger in any holes to check. Now you can pour in gear lube from the top. Great design!


I have one, and I think these trucks for their cost should have this as standard. Gotta love the dipstick! But it is nice sometimes to need the finger for probing a hole. (No not A-Hole)http://www.dieselplace.com/forum/smileys/Embarrased.gif

OK, now that I've actually been under my rig and inspected the diff, I gotta ask: where do you get a square drive for the drain plug? I checked the local auto parts and Home depot but to no avail. Any suggestions? Also, anyone using Mobil 1 75-90 under towing conditions?


thanks!


Don

OK, now that I've actually been under my rig and inspected the diff, I gotta ask: where do you get a square drive for the drain plug? I checked the local auto parts and Home depot but to no avail. Any suggestions? Also, anyone using Mobil 1 75-90 under towing conditions?


thanks!


Don








Ratchet without a socket.

The dealer lubrication service manual says that there should be something like 2-3 quarts in the rear end. The owner's manual says it should be near the filler plug. My dealer has an oil change facility and the quantity info was in their lubrucants book. They also indicated filling to the plug should be no problem.


Anyway, there is GM documentation that says it can be well below the filler hole. http://www.dieselplace.com/forum/smileys/Confused.gif

Just changed the rear fluid this past weekend. (1100 miles) Much easier than the old units without a drain plug. Will be towing our 5th wheel with Mobil 1 in the rear differential.


As others had stated, rear fluid was low from the factory. I collected about 2 1/2 quarts.

OK, now that I've actually been under my rig and inspected the diff, I gotta ask: where do you get a square drive for the drain plug? I checked the local auto parts and Home depot but to no avail. Any suggestions? Also, anyone using Mobil 1 75-90 under towing conditions?


thanks!


Don





Any 1/2" square drive will work! As stated above, a 1/2" drive ratchet works best.


As for Mobil 1 gear lube. I use it and have for the past 50,000 miles. I am a weekend tow type for the most part. When I do tow it is about 16,500# CVW once in a great while I will tow upwards of 21,000# CVW ( Once I towed more then 32,000# CVW, but only to help out a friend that had broke down) and so far the lube works great.

So here it is...


After reading many posts in this forum (all excellent, by the way) I decided that I too would not be ripped off by $26/qt "holy water" (as another member puts it). So, I went with the Mobil 1 and changed it last Thursday just before a trip from Las Vegas to Flagstaff via Laughlin, NV. w/ TT, wife, dog, etc.


Today, feeling like I was missing some special additivies or that the system just wasn't 100% to spec, I caved and went out and bought the "holy water"! I replaced the Mobil 1 this afternoon.


The saving grace? If it can be considered as such, I figure that after having not changed the fluid from the day I drove it home until I was at about 17,500 mi and already had over 500 mi towing about 5300# (GVW 13,000#), the Mobil 1 served to sort of "rinse out" the system. When I drained out the M1 it certainly wasn't as clean as when I put it in. Even the drain plug had a fresh layer of muck on it.


So, if you're like me and haven't been paying much attention to you investments lately, a 500 mi run with a cheap alternative might be the ticket before you too cave and get the gold.


Thanks to everyone and their posts--hope this helps someone.


(now on to performance issues!)

Holy Water?


Do tell.


My truck is right around 3000 miles and I have not changed anything yet.


I think I would like to replace all of the fluids with some excellent stuff.


GarEdited by: biggar

Just did mine with a 3/8 drive ratchet. BTW if you jack up the passenger side rear, and not the driver's side, and tilt the axel, you can get about another quart in there.

Holy Water?


Do tell.


My truck is right around 3000 miles and I have not changed anything yet.


I think I would like to replace all of the fluids with some excellent stuff.


Gar








The "holy water" comment comes from another member and refers to the cost/qt for the GM specified synthetic rear end gear oil. At about $26/qt compared to $6.95 for Mobil 1, you'd think you were paying for liquid gold. My point of view is that I expect to have this truck about twice as long as I'm paying on it or more--I bought the service contract and extended it from 75k to 100k, got the GAP insurance, the whole thing. If there's a question about what voids the warranty then I have to go spec just for peace of mind.


btw: when it says on the bottle "skin irritant", believe it--I got some on my forearms and it felt like fiberglass...

Thanks.


I will likely go with Amsoil or Mobil1.





Gar

I use mobil 1 75-90 and have on both of my Dmaxes. No problems. Like others said I only had about 2 qts in mine at the initial 500 mile drain. I always seem to get in about 4 1/8 qts in mine. 2 in the front.