You're the one rolling the dice.
Servicing Differential, '03 Durango
2003 Durango 4x4, 4.7l 9.25 lsd rear
I made a post a couple weeks ago about my differential, It was noisy at low speed turns and I changed the fluids and found some broken pieces of the clutch pack in the case.
I bought the clutch rebuild kit, and I found a web page that features a rebuild where the owner found himself in EXACTLY the same position: During a fluid change, he found clutch pack parts that had fallen off but nothing else had been damaged.
In that write up, he postulates that if you count off the number of turns you had to loosen the adjusters to get the gearset out, then you can get the preload and backlash "close enough" when re assembling. In his write up, it appeared he replaced ONLY the clutch pack.
I bought the two bearings, the cup and cone items that go on the left and right side of the differential...(not bothering with the pinion end)--However if I replace those carrier bearings, the whole "count the turns" deal is out the window right? Certainly a new set of carriers is going to be different...they wont wind up being at necessarily the same as far as the preload and backlash, right?
So, that leads me to want to stay with the original bearings if they look okay. Is that totally nuts or what? Im not looking for another 100,000 miles here, Id be happy with 30 or 40k. I also am not gonna spend $1100 to have it rebuilt "professionally" either. I got the run out gauge, and the marking paint but Ive never done this type of work.
Im sort of feeling like my best chance is to stay with the original bearings and double check the backlash when installed again. I dunno. Im doing all of this ahead of a long trip for a vacation! We will be driving it down the beach somewhat. I also pull a boat with it.
Any comments would be appreciated!
I made a post a couple weeks ago about my differential, It was noisy at low speed turns and I changed the fluids and found some broken pieces of the clutch pack in the case.
I bought the clutch rebuild kit, and I found a web page that features a rebuild where the owner found himself in EXACTLY the same position: During a fluid change, he found clutch pack parts that had fallen off but nothing else had been damaged.
In that write up, he postulates that if you count off the number of turns you had to loosen the adjusters to get the gearset out, then you can get the preload and backlash "close enough" when re assembling. In his write up, it appeared he replaced ONLY the clutch pack.
I bought the two bearings, the cup and cone items that go on the left and right side of the differential...(not bothering with the pinion end)--However if I replace those carrier bearings, the whole "count the turns" deal is out the window right? Certainly a new set of carriers is going to be different...they wont wind up being at necessarily the same as far as the preload and backlash, right?
So, that leads me to want to stay with the original bearings if they look okay. Is that totally nuts or what? Im not looking for another 100,000 miles here, Id be happy with 30 or 40k. I also am not gonna spend $1100 to have it rebuilt "professionally" either. I got the run out gauge, and the marking paint but Ive never done this type of work.
Im sort of feeling like my best chance is to stay with the original bearings and double check the backlash when installed again. I dunno. Im doing all of this ahead of a long trip for a vacation! We will be driving it down the beach somewhat. I also pull a boat with it.
Any comments would be appreciated!
1 - 6 of 6 Posts
If the carrier bearings are rough turning or pitted, replace them. Get a service manual. The 9.25" corporate axle was used for many years in many applications. It doesn't specifically have to be for a 2003 Durango, but one would be helpful if you will be performing higher-echelon work like this. The public library may have a FSM or a general Chiltons that covers a rebuild and gives procedures, measurements and torques.
With the differential out, measure the turning torque of the pinion yoke nut with an inch-pound torque wrench. You can set carrier bearing preload if you know the pinion bearing drag in inch-pounds. Just subtract that amount from the total pinion and differential turning torque for the differential bearing preload.
Adjust the left and right side bearings until you reach the preload amount (for new bearings) while also achieving the correct gear backlash.
A tooth contact print should verify that most contact is in the middle of the tooth on both the drive and coast sides of the tooth. Adjust until the best contact is achieved.
Clean the inside of the housing thoroughly and use a 75W-140 synthetic hypoid lube with the 'posi' friction modifier additive.
With the differential out, measure the turning torque of the pinion yoke nut with an inch-pound torque wrench. You can set carrier bearing preload if you know the pinion bearing drag in inch-pounds. Just subtract that amount from the total pinion and differential turning torque for the differential bearing preload.
Adjust the left and right side bearings until you reach the preload amount (for new bearings) while also achieving the correct gear backlash.
A tooth contact print should verify that most contact is in the middle of the tooth on both the drive and coast sides of the tooth. Adjust until the best contact is achieved.
Clean the inside of the housing thoroughly and use a 75W-140 synthetic hypoid lube with the 'posi' friction modifier additive.
An update:
I finished up yesterday. The write up I was following was good, but left out a few things.
First of all, that whole count the turns on the adjusters bit was total BS. Unless you had some sort of degree wheel on the end of your home made adjuster wrench, (which I can envision, but why, oh why) The thing is, the amount of turn needed on the adjuster to make a difference in the backlash is SMALL. No way is "1 and a half turns" going to do you any good. 1.458 turns maybe. How are you going to discern that right? Another thing worth noting, if you back the adjusters off enough, they will fall through the threaded area, and then you just lost count on the number of turns! This happened to me, but it lead me to just go ahead and replace the carrier bearings since I had to set the preload and backlash from scratch at that point anyway.
The author also might have mentioned that the ring gear bolts were reverse threaded. The assumption is that one who would be reading this article is doing so to make a novice attempt at servicing a differential, so why would anyone know that?
I was a fiend with my long homemade spanner, back and forth on the adjusters, until I got them both snug, with the backlash that I wanted...
The whining noise at low speed turns is gone, and the whole thing just feels smoother than it did before. I noticed before taking it apart that the one side had more play in it than the other, that turned out to be the side where the clutch pack was coming apart.
The whole process was made simpler because I did not disturb the pinion. So, rebuilt the clutch pack and new carrier bearings. Now lets see how long it lasts! I am feeling pretty good about it though!
Thanks everyone.
I finished up yesterday. The write up I was following was good, but left out a few things.
First of all, that whole count the turns on the adjusters bit was total BS. Unless you had some sort of degree wheel on the end of your home made adjuster wrench, (which I can envision, but why, oh why) The thing is, the amount of turn needed on the adjuster to make a difference in the backlash is SMALL. No way is "1 and a half turns" going to do you any good. 1.458 turns maybe. How are you going to discern that right? Another thing worth noting, if you back the adjusters off enough, they will fall through the threaded area, and then you just lost count on the number of turns! This happened to me, but it lead me to just go ahead and replace the carrier bearings since I had to set the preload and backlash from scratch at that point anyway.
The author also might have mentioned that the ring gear bolts were reverse threaded. The assumption is that one who would be reading this article is doing so to make a novice attempt at servicing a differential, so why would anyone know that?
I was a fiend with my long homemade spanner, back and forth on the adjusters, until I got them both snug, with the backlash that I wanted...
The whining noise at low speed turns is gone, and the whole thing just feels smoother than it did before. I noticed before taking it apart that the one side had more play in it than the other, that turned out to be the side where the clutch pack was coming apart.
The whole process was made simpler because I did not disturb the pinion. So, rebuilt the clutch pack and new carrier bearings. Now lets see how long it lasts! I am feeling pretty good about it though!
Thanks everyone.
Glad to hear that. I'm geting ready to install a 2003 9.25" axle in my 1999 Dakota to upgrade to the rear disc brakes and get rid of the 1999's noisy rear axle. I guess I need to look over the 2003 axle before the install.
Just an update, she's got almost 3000 miles on it since the job, and works great. Even had it down the beach a few times. Funny thing happened when we were on vacation...we were in the Hotel parking lot, and saw a Durango coming in the lot similar to ours. You know how when you buy a car alll of a sudden you notice them everywhere? Well this one slowed down to turn into a parking spot, and guess what? It made that familiar undulating whirring noise! LOL! My wife and I both got a chuckle out of that. Must be a pretty common thing for those track lock units!
1 - 6 of 6 Posts
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