Hi guys it has been a while since i have been on here. i have a whining noise above 40mph and when you let off the gas it goes away for a second and comes back and then when you give it gas it goes away for a second and then comes back. The local shop said i need a new ring and pinion and all new bearings. There is no play in in the driveshaft or yoke. They said it would cost 1500$ for a rebuild and it would take 5 hours. The parts are only $350 and labour is only $100 a hour so i dont know what to think. i noticed it started after i changed the fluid and yes i added friction mod. BTW its a 98 durango 4x4 with 318 and 9.25 RE with 3.90 gears.

 

I have the same humming sound too, especially if you're cruising at around 40MPH. A shop told me the ring and pinion gears just need to be adjusted with shims so they mesh correctly. If you're considering doing the work yourself, it would be easier to buy a new ring and pinion gear set (when they are sold together, they are made to match each other perfectly) check out the service manual for your D on these forums to see what you're getting into, I forget if you need any special tools or not, but I do remember there's a lot of fine adjustments you need to make to set the gears properly. Hope this helps.

 

If you don't know what you're doing replacing the ring an pinion can prove catastrophic if you don't do it right. Typically something you want to pay a professional that has experience doing.

Check out here if you're wanting to buy it:

http://www.ringpinion.com/

Also could be a bad bearing in the rear end.

 

Thanks yeah i am not going to attempt it my self i think i can get away with new bearings it just started this noise recently. I am taking it in here soon to have a guy put it on a lift and drive it and listen with a stethascope.

 

I also have the same issue.. ironically, with the same year and setup truck...

 

Yeah it is making me mad when guys at shops just say Oh you need a whole rebuild. And then when i ask them why and what parts they start laying out the B.S. I heard that U joints can make the same noise?

 

Yep the U-Joint in the rear end connecting driveshaft is one of the first places I'd check.

 

Indeed, check all the cheap stuff first then move onto the more expensive things to replace. If there are no vibrations at all then odds are your u joints are fine but you never know.

 

It also could be a bad axle bearing.


Now the rear end has shims only on the Pinion, the carrier bearings preload and backlash are set via threaded caps holding the outer carrier bearing races on each side where the axle housings meet the differential housing.

So to set the backlash you would remove each wheel, and axle, then you have to have something long enough with a 32mm hex head to reach the caps and thread one out and one in to move the ring gear closer to the pinion gear and set the preload and backlash tolerances.


But to simply pull the old ring and pinion and swap to a new you would have to shim the new pinion correctly, then set the ring gear to specs. This is a LOT harder to do then swap bearings and reinstall the same old pinion and ring gear that is already set up with the right shims, (if the gears are good!).


One thing I would do first is go buy a second 4oz bottle of Friction Modifier and add it as well. 2 Bottles won't hurt and I have seen people do that and "fix" the issue. The thing is, the clutch packs usually "chatter" and wine slightly around corners and usually not driving straight down the road?????

Hope you used 80W-90 conventional or 75W-90 Fully Synthetic. You should have used at least 7oz of Friction Modifier for your Chrysler Corporate 9.25 rear differential.

Changing the fluids had nothing to do with a bearing going out. It's most likely from lack of maintenance, bad bearing construction, excessive mileage, or worn clutch packs. Putting it on a rack is going to be your best diagnosis.

$1500 for just replacing the bearings is straight up hwy robbery! If it comes down to the bearings needing replaced shop around at your smaller local shops. I paid $1400+ tax for both front and rear re-gear and re-bearing with top quality Yukon parts just last month!