Rear End Question

[yurtle]

'98 Series TXT. The last time I drove my buggy in water up to the floorboard, it started make grinding noise while driving. I was hoping it was the brakes or the rear end.

I fixed the brakes so the star wheel auto adjuster works again. I ground off the drum ridge and have them set so they just barely don't drag. I still need to adjust the compensator, but the grinding noise occurs even when the drums aren't installed.

I dropped the rear end pan and was going to replace the oil, but I found no evidence or grit or metal shavings in the oil. I have it up on jack stands, but I can't really tell if it's the wheel bearings, the gears, or the motor. The wheels were completely submerged, so I'm wondering if it's the wheel bearings. Are they lubricated by the differential oil? If so, I might filling it with gasoline and do a thorough flushing before refilling.

I guess the motor could have shot bearings or brushes, but it's a 2004.

I hate the thought of removing the rear end, but that may make troubleshooting and repair easier.

Thoughts?

[kab69440]

Sounds like a dry bearing, from your description. If it still makes the noise while running on jack stands, a stethoscope could be your new best friend in locating which one(s).

[yurtle]

Originally Posted by kab69440

Sounds like a dry bearing, from your description. If it still makes the noise while running on jack stands, a stethoscope could be your new best friend in locating which one(s).

Exactly. A dry bearing with fine grit in it. That's what it sounds like. Not at all what you'd expect to hear from inside the bearings inside the oil bath.

Yep. Got a medical one, but I've always used a metal or wooden stick or a piece of tubing, depending on what I'm lookin' for.

I guess my wife will have to be my new best friend, and operate the throttle while I listen around, and hope she doesn't knock it off the jack stands while I'm under it. Yesterday, I was spinning it up, then running to listen to each part while it spun down.

I forgot I had a copy of the Dana rebuild and parts manual, so I now see there's a seal before the bearing, so the bearing is apparently not normally lubricated by the differential oil.

Another question. I was surprised how much slop there was in the "differential gear assembly", as it's called in the Dana Axle Shop Rebuild and Service Parts Manual. When I rotate the driver's side wheel forwards then backwards, there is more slop than I would have expected. Maybe that's normal, as I've never noticed a clunk when reversing directions, like we used to hear when a rear wheel drive universal joint was going bad.

[bigstik40]

As you noted, the assembly has the oil seals between the axle bearings and the gears. That would mean that in deep water your bearings would be exposed but the differential "innards" and oil would not. The axle bearings are probably the sealed or shielded type and full of grease, which would help keep water out, but an older bearing may no longer seal that well. As far as the amount of backlash when rotating the rear wheels, my 2008 seems to have an excessive amount for its condition. (probably normal). A lot of that "backlash" is in the differential spider gears. Best bet would be to pull the drums and clean and dry everything to see if that helps. I would grease the spline area and nuts prior to reassembly to keep it from rusting together. Good luck - RAY

[yurtle]

Originally Posted by bigstik40

As you noted, the assembly has the oil seals between the axle bearings and the gears. That would mean that in deep water your bearings would be exposed but the differential "innards" and oil would not. The axle bearings are probably the sealed or shielded type and full of grease, which would help keep water out, but an older bearing may no longer seal that well. As far as the amount of backlash when rotating the rear wheels, my 2008 seems to have an excessive amount for its condition. (probably normal). A lot of that "backlash" is in the differential spider gears. Best bet would be to pull the drums and clean and dry everything to see if that helps. I would grease the spline area and nuts prior to reassembly to keep it from rusting together. Good luck - RAY

I pulled the drums this past weekend, and pulled the whole assembly, in order to fix the star adjuster mechanism. The pivot pin can't be removed without removing the assembly from the axle. One of my auto adjusters was either worn or bent. I replaced the shoes a couple of years ago, and one side was auto adjusting, but the other side wasn't. I cleaned and injected grease into the bearing as best I could. It still grinds.

I'll still try kab69440's suggestion to try and pinpoint the exact location of the noise.

I'll probably end up dropping the whole rear end. I'd like to tear open the motor to check the brushes, and I'll probably just replace the wheel bearings, and any seals that look suspect. It's a 1998 with a 2004 motor, and it's really the only thing I haven't torn into yet.

[kab69440]

Ayup. A listening stick works well too. A chunk of hickory broom handle is the preferred listening device for Roots style air compressors, as it allows you to hear bad bearings without having your eardrums explode.

[yurtle]

Originally Posted by kab69440

Sounds like a dry bearing, from your description. If it still makes the noise while running on jack stands, a stethoscope could be your new best friend in locating which one(s).

Originally Posted by yurtle

Yep. Got a medical one, but I've always used a metal or wooden stick or a piece of tubing, depending on what I'm lookin' for.

Originally Posted by kab69440

Ayup. A listening stick works well too. A chunk of hickory broom handle is the preferred listening device for Roots style air compressors, as it allows you to hear bad bearings without having your eardrums explode.

An old-schooler! I actually know quite a bit about Roots compressors. In my experience, folks like you describe are a dying breed. It helps the bottom line to lay off or early retire anyone who has experience and hire a buncha kids who know nothing, but are cheaper.

[kab69440]

Compared to a lot of folks, I am one of those know-nothing "kids'". I am 41.

[Gonkulor]

Originally Posted by kab69440

Compared to a lot of folks, I am one of those know-nothing "kids'". I am 41.

If it weren't for you meddling kids and that dog!

[yurtle]

Originally Posted by kab69440

Compared to a lot of folks, I am one of those know-nothing "kids'". I am 41.

I was a "know it all" at that age.

I didn't mean to offend, and referring to much younger and much less experienced factory reps. I don't see nearly as many grey-haired folks as I used to, when it comes to starting up or troubleshooting equipment. It's not their fault, they often don't have any grey-haired elders they can learn from. The same time everyone was worried about seccession planning, they were getting rid of the folks who used a nickle on its side to check for vibration and a broomstick to listen to noise, and knew "good" noises from "bad" ones.