Broken Ring Gear......

[FelixNDiva]

So our coach is at Camping World to have the roof sealed and the slide covers replaced. I get a call from the service manager yesterday stating that there is a problem with our coach. Evidently they had to remove the coach from the service bay for some reason and in doing so backed it into a very soft area and got stuck. The person driving the coach attempted to rock our coach back and forth to get out of the mud. This action resulted in breaking the ring gear in the differential. IM NOT HAPPY...... They are replacing the gear. But should I be concerned about any other components of the drive train? My biggest concern is to get on the road and have a failure in the middle of nowhere.

Any advice would be great..

Thanks

[RobbieH]

We break ring gears in our rock crawlers pretty often. It takes a LOT to break a ring gear in our rigs, I can only imagine how much force it takes to break a ring gear in an RV's huge differential.

They can't just replace the ring gear. They need to replace the ring and pinion both, and they need to properly set the gear lash. This is not a job for an amateur. If they don't have someone there that knows how to set gears, they need to bring in a pro. If I were you, I would make them replace the bearings too, since they are in there, and because you don't know what sort of metal fragments have gotten into them. So, R&P set, new seals and bearings, and a pro doing the job.

[twinboat]

Wow, the shock thru the drive train would have been extreme. I snapped a truck axle and it sounded like a bomb.

If they actually broke the ring gear or pinion gear, look for twists in the drive shafts and axle splines.

If they blew out the spider or side gears, that can happen from spinning one wheel fast. Less shock but more sheaded steal flying around.

Make sure a pro looks it over.

[Unplanned Tourist]

An acquaintance of mine broke teeth off his crown by trying to rock his DP back and forth also. He ended up putting in a complete rebuilt center section because one of the threaded bolt holes that hold the side bearing caps on was stripped out. So I would suggest that a competent gear shop do the work on your diff. I have rebuilt many truck diffs and must say that they do need to be set up properly or they will fail prematurely.

[RobbieH]

Oh, once they fix it, you need to follow break-in procedures unless the manufacturer of the R&P says you do not. Ask for the instructions that come with the parts so that you know what their specified heat treat break-in procedure is. If you do not, the R&P never get a chance for the metal to harden, and the first time you need to put some pressure on them, the teeth will cut right off the ring gear.

Here is the procedure I follow:
After driving the first 15 to 20 miles, stop and let the differential cool before proceeding. Keep the vehicle at speeds below 60 mph for the first 100 miles. I also recommend putting at least 500 miles on the new gear set before heavy use or towing. During the first 45 miles of towing, it helps to go about 15 miles at a time before stopping to let the differential cool for 15 minutes before continuing. This is necessary because not all of the gear tooth is making contact until it is heavily loaded. When towing, the teeth flex to contact completely, and cause the previously unloaded portion of the teeth to touch and work harden. It is very easy to damage the ring & pinion by overloading before the teeth are broken-in.

[FelixNDiva]

Thanks for the replies. They are sending the Pumpkin out for repairs. I am going to do some follow-up with the vender.

OH I could ring some ones neck right now.......

[Unplanned Tourist]

Originally Posted by RobbieH

Oh, once they fix it, you need to follow break-in procedures unless the manufacturer of the R&P says you do not.

I'm not sure where you got this from, but when I rebuilt diffs, they would go straight to work. 2 diffs (tandem drive) pulling up to 160,000 pounds up and down the mountains. No break-in for those and they are usually good for 1,000,000 miles. I have never heard of a "break-in" time for gears. Where did you get that from? Always good to check for leaks, etc. after driving a short while though.

[RobbieH]

Originally Posted by Unplanned

I'm not sure where you got this from, but when I rebuilt diffs, they would go straight to work. 2 diffs (tandem drive) pulling up to 160,000 pounds up and down the mountains. No break-in for those and they are usually good for 1,000,000 miles. I have never heard of a "break-in" time for gears. Where did you get that from?

Just from Randy's Ring & Pinion. I figure they know what they are doing.
https://www.ringpinion.com/Technical...r_break-in.inc

We've seen them fail when not broken in properly.

It is kind of scary in a rig like mine (my rock crawler) that never sees highway speeds or use. They may never get heat cycled in their entire life.

There are some gear sets that say they do not need the break-in period. But I tend to think safe is better than sorry.

[IC2]

I suspect that Randy's Gear has a good reputation for building the venerable Ford 9" and GM 10 bolt diffs and that break in procedure is good for 4.10 ratios and higher that tend to run hotter then the lower number ratios. It's a bit too conservative for a heavy truck Eaton, Sterling, Dana or similar axle in a MH. I would consider a heat and cool cycle then after a few hundred miles that the gear oil be changed and the housing flushed, particularly if the OP doesn't/can't witness the disassembly, cleaning and reassembly. As far as what components need to be changed - ring, pinion, side gears, all bearings and all seals and if it has a locking assembly, at least at a minimum, disassembled, cleaned and reassembled. When a differential self destructs, shrapnel goes through out that entire axleassembly - and usually with a very loud bang.

Dang, don't you just adore CW??

[RobbieH]

In our group, nobody runs a GM axle smaller than a 14 bolt. 10 bolts go POW!

Well, I'd put a 12 bolt in my Firebird. I'm still waiting for the stock 10 bolt (with spool) to blow up. Luckily the tires on it don't get any traction.

[Unplanned Tourist]

Originally Posted by RobbieH

Just from Randy's Ring & Pinion. I figure they know what they are doing.
https://www.ringpinion.com/Technical...r_break-in.inc

We've seen them fail when not broken in properly.

I'm sorry, but Randy's Ring & Pinion" are just covering their butt with this "break-in" routine. How long do the guys at the drag strip spend breaking in the gears? I have spent a lot of time at a drag strip, and never saw anyone. These are hypoid gear sets that are "generated" similar to forging, and then heat treated. If you ever rebuild a diff, you will know about checking the contact patch, and how it climbs under load.
By the way, how many MH's have the diffs "broken in" when coming out of the factory? None.

[RobbieH]

I like to sway on the side of safe than sorry. If mine were getting replaced, I'd cycle them. I have on everything other than my rock crawler.

[FelixNDiva]

To follow up.... I visited my buddies at CW, first to let them know how pissed I am and second to see my coach and the damage done. They have the complete rear end dissembled the axels are out, all bearings have been removed. The differential has been sourced out to a very reputable heavy equipment shop. Everything in the differential will be replaced. I requested that I be contacted when the diff is returned so that I can inspect. I told them that I wanted to see all of the old parts and the build sheet. The axels will be checked for straightness and the splines will be checked for any cracking. I also requested that the U-Joints be replaced..... After several stink-eye looks they agreed to replace them. I feel that they are doing their due diligence to make all of the necessary repairs and to restore my confidence. We will see.

Thanks Jeff

[Dtwallace]

Originally Posted by RobbieH

Oh, once they fix it, you need to follow break-in procedures unless the manufacturer of the R&P says you do not. Ask for the instructions that come with the parts so that you know what their specified heat treat break-in procedure is. If you do not, the R&P never get a chance for the metal to harden, and the first time you need to put some pressure on them, the teeth will cut right off the ring gear.

Here is the procedure I follow:
After driving the first 15 to 20 miles, stop and let the differential cool before proceeding. Keep the vehicle at speeds below 60 mph for the first 100 miles. I also recommend putting at least 500 miles on the new gear set before heavy use or towing. During the first 45 miles of towing, it helps to go about 15 miles at a time before stopping to let the differential cool for 15 minutes before continuing. This is necessary because not all of the gear tooth is making contact until it is heavily loaded. When towing, the teeth flex to contact completely, and cause the previously unloaded portion of the teeth to touch and work harden. It is very easy to damage the ring & pinion by overloading before the teeth are broken-in.

I have to ask Robbie, where in the world did you get that information from?

40 plus years of heavy vehicle maintenance and I've never heard of tempering the gears of a differential in a break in period. There is no break in of the differential, it's setup right, from the beginning, and you drive off without a care.

Next, I would have the transmission serviced by a reputable shop on CW's dime.

There are proper ways to rock a vehicle out of a rut, and there are improper ways, apparently if they broke a ring gear, and I don't think that's the case,
they abused the hell out of the transmission to get it out the improper way.

This is a real dark cloud hanging over you peace of mind now, you don't know what will fail next from the apparent abuse they've inflicted on your coach.

Sorry you had to go through that, and wishing you the best of luck.

DTW