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-   -   Grinding Noise... low differential fluid? (http://www.jeepgarage.org/f203/grinding-noise-low-differential-fluid-44546.html)

Jamesla30 07-10-2012 06:58 PM

Grinding Noise... low differential fluid?
 
I have a pretty annoying grinding noise that happens usually at very slow speeds. It is strange as it seems to happen right after moving from a stop, and right before shifting from 1st to 2nd gear. It will also grind continuously if I'm going about 10 miles per hour and keep the rpm just right (like right before a shift, but not enough rpm to let it shift). Once I let off the gas, or if i shift to neutral, the noise immediately goes away. It makes no noise when in park and revving the engine.

I am thinking it has something to do with the differential. The transmission seems to shift fine, i haven't noticed any slipping or clunks with it.

Could low differential fluid or improper fluid ratios cause this problem?

I have a 99 WJ V8 w/ Quadradrive, which uses the special fluid....

PLEASE HELP!

01grand 07-11-2012 03:10 PM

Re: Grinding Noise... low differential fluid?
 
It could be a problem with a few things, since you said it only happens when moving I will stick with driveline parts that move the vehicle. I would check both the transfer case and differentials for low fluid and any problems with the fluid. If you haven't changed them its probably a good idea to do it anyway. The transfer case takes Mopar NV247 transfer case fluid, also known as mobil fluid 424 or amsoil has an equivalent hydraulic tractor fluid. It takes less than 2 quarts so it can be done for $20 or less yourself. The diffs take synthetic 75w-140 gear oil, nothing really special but you may need a limited slip additive (although many leading sythetic gear oil makers say an additive is included, such as royal purple, amsoil, mobil, and valvoline). I have heard different stories on whether extra additive is needed for quadradrive, so far mine have been ok on RP, but I will be going to amsoil soon. Diff oil is a little more expensive, about $30-40 per axle (about 1.5 qts for the front and close to 2 qts for the rear)

Jamesla30 07-11-2012 05:16 PM

Re: Grinding Noise... low differential fluid?
 
Quote:

Originally Posted by 01grand (Post 655143)
It could be a problem with a few things, since you said it only happens when moving I will stick with driveline parts that move the vehicle. I would check both the transfer case and differentials for low fluid and any problems with the fluid. If you haven't changed them its probably a good idea to do it anyway. The transfer case takes Mopar NV247 transfer case fluid, also known as mobil fluid 424 or amsoil has an equivalent hydraulic tractor fluid. It takes less than 2 quarts so it can be done for $20 or less yourself. The diffs take synthetic 75w-140 gear oil, nothing really special but you may need a limited slip additive (although many leading sythetic gear oil makers say an additive is included, such as royal purple, amsoil, mobil, and valvoline). I have heard different stories on whether extra additive is needed for quadradrive, so far mine have been ok on RP, but I will be going to amsoil soon. Diff oil is a little more expensive, about $30-40 per axle (about 1.5 qts for the front and close to 2 qts for the rear)

Is changing the transfer case and differential oils something I could try to do myself? I have no lift or way to get my Jeep off the ground... I am technically saavy, used to change my oil myself all the time. But never done anything with TC or D and crawling underneath the Jeep is always a pain. How much would it cost a shop to do both for me? Should I go to a dealer to ensure they do it correctly with the right fluids? Thanks for your help.

01grand 07-11-2012 06:57 PM

Re: Grinding Noise... low differential fluid?
 
A dealer should have the right fluids to use, depends on the outside shop if they care enough to look up the right specs and use the right fluid. They SHOULD but.... they cut corners sometimes too. The transfer case can be done on the ground, but you have to lift the body up so the axles drop enough that you can get to the diff cover to remove it. Otherwise its regular bolts on the diff covers and hex plugs on the tcase. Just pull the fill plug to make sure it comes out (upper plug) and then remove the drain plug with a pan underneath. Once drained you can fill it back up with a cheap fluid pump from the auto store. But if you aren't sure about it it would be best brought to a shop. Out of curiosity you don't happen to live in MN do you?

Jamesla30 07-11-2012 07:40 PM

Re: Grinding Noise... low differential fluid?
 
Quote:

Originally Posted by 01grand (Post 655223)
A dealer should have the right fluids to use, depends on the outside shop if they care enough to look up the right specs and use the right fluid. They SHOULD but.... they cut corners sometimes too. The transfer case can be done on the ground, but you have to lift the body up so the axles drop enough that you can get to the diff cover to remove it. Otherwise its regular bolts on the diff covers and hex plugs on the tcase. Just pull the fill plug to make sure it comes out (upper plug) and then remove the drain plug with a pan underneath. Once drained you can fill it back up with a cheap fluid pump from the auto store. But if you aren't sure about it it would be best brought to a shop. Out of curiosity you don't happen to live in MN do you?

Colorado.

Jamesla30 07-11-2012 09:46 PM

Re: Grinding Noise... low differential fluid?
 
Sounds like its gonna cost $500 or more to have a shop or the dealer do the transfer case and diffs fluid replacements. And another $300 or more if I do a transmission fluid replacement too. Being that i'll probably be ordering a 2014 in December or January, I think i'll pass on the issues for now.

Could I just buy some oil and fluid and fill the transfer case and diffs if they are getting low? Anyway to tell if they are low? Can I just fill to the top and call it good?

I do remember a shop telling me a while ago that the diff and/or transfer case both had leaks....

01grand 07-11-2012 10:56 PM

Re: Grinding Noise... low differential fluid?
 
You can certainly top them off if they are low. Again for how cheap it is I would recommend just draining and refilling the transfer case, $20 for fluid and its only 2 quarts. If you can crawl under the truck on the ground you can do it. Either way, fill it until some fluid starts dribbling out of the fill hole. You can do that for the diffs but that would be slightly over full (maybe not a bad idea if they are leaking) otherwise they should be about 1/4" to 1/2" below the fill holes if I remember correctly.

Frango100 07-12-2012 05:12 PM

Re: Grinding Noise... low differential fluid?
 
If you did your oil changes before, i would say that T-case and diffs are not a big deal to do yourself as well. I do it myself as well and its no rocket sience by far:D
As Aaron said, T-case is just removing the fill plug and then the drain plug (only in that order to prevent to end up with an empty T-case and a rotten in place fill plug), Just fill it up until it starts overflowing.
For the diffs there is no drain plug, you have to remove the cover and need RTV to seal it again when installing. Only for the rear you have to jack it up a bit to get access to the upper cover bolts, but for the rest nothing difficult. Takes you less then an hour per diff working slowly and saves you big money and gives a good feeling when done.
You could ofcourse just fill it all up and call it the day and keep an eye on the level once in a while.

Jamesla30 07-12-2012 10:11 PM

Re: Grinding Noise... low differential fluid?
 
Thanks guys, can you give me a list of what oil/fluids and quantity I need for the transfer case and diffs? Any types/brands you would recommend? Can I get these at any parts store?

Can I fill diffs (not replace) without having to jack anything up? Are the fill plugs accessible from underneath when on the ground as normal?

Jamesla30 07-12-2012 10:14 PM

Re: Grinding Noise... low differential fluid?
 
Also, the diffs don't have a rubber gasket? Just RTV? Anything special when applying that? Just make sure it goes around all the way with no gaps?

Now that we are talking about it, it really doesn't sound that difficult... so why are shops trying to charge $150-250 per diff/tc to do it??? Does it really take them a couple hours to do each? Wouldn't seem likely, especially with a lift.

01grand 07-13-2012 11:33 AM

Re: Grinding Noise... low differential fluid?
 
They charge that much because they can. lol. You need 2 quarts of fluid for the transfer case, the dealer is the best bet for that otherwise if you can find mobil 424 it will work as well, but I haven't seen that at any parts stores by me. The gear oil is a 75w-140 weight, and make sure to get synthetic. 4 quarts is enough to do both diffs with about 1/2 a quart left over. You will need to jack it up to get at the top bolts on the rear end, but you shouldn't need to for the front. You can always get a siphon pump to remove the gear oil from the diffs but that can be a long process with how thick gear oil is and doesnt ensure all the old fluid is out. Black RTV will work perfect to seal up the cover to the diff, just make sure to get a good bead all around and let it cure for a bit before adding oil. My trick is to pull one cover off, drain, clean, and reseal it, then go do the same on the other axle. Then go back and fill up the first one and then fill the second. You could even do the tcase in between sealing and filling the diffs. If they are leaking from around the cover like you said I would definitely go with taking the covers off rather than the siphon method, I heard from someone that the shops will do the siphon rather than deal with taking the covers off. :glare:

Jamesla30 07-13-2012 02:22 PM

Re: Grinding Noise... low differential fluid?
 
Quote:

Originally Posted by 01grand (Post 655976)
They charge that much because they can. lol. You need 2 quarts of fluid for the transfer case, the dealer is the best bet for that otherwise if you can find mobil 424 it will work as well, but I haven't seen that at any parts stores by me. The gear oil is a 75w-140 weight, and make sure to get synthetic. 4 quarts is enough to do both diffs with about 1/2 a quart left over. You will need to jack it up to get at the top bolts on the rear end, but you shouldn't need to for the front. You can always get a siphon pump to remove the gear oil from the diffs but that can be a long process with how thick gear oil is and doesnt ensure all the old fluid is out. Black RTV will work perfect to seal up the cover to the diff, just make sure to get a good bead all around and let it cure for a bit before adding oil. My trick is to pull one cover off, drain, clean, and reseal it, then go do the same on the other axle. Then go back and fill up the first one and then fill the second. You could even do the tcase in between sealing and filling the diffs. If they are leaking from around the cover like you said I would definitely go with taking the covers off rather than the siphon method, I heard from someone that the shops will do the siphon rather than deal with taking the covers off. :glare:

Thanks, I'm getting ready to do this... last few questions:

1. What do I need to lift the rear end? Will the stock jack work, or should I go buy a floor jack? Where do I put the Jack to lift in the rear?

2. You mentioned "cleaning" the diffs... what is involved in that. Wash out with water, let dry, etc? Or avoid water, and just use a towel to wipe out?

3. I have heard this transfer case needs a special fluid.. its quadradrive (NV247 I believe)... where do I get that and what ratios do I use? Or will the Mobil 424 work without adding additive?

4. Lastly, is there any write-ups anywhere with details on either of these jobs?

Thanks so much again guys!


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