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mustang guy · 11-19-2015, 04:05 PM

Hi, im in the process of trying to fix a 95 monaco dynasty with 8.3 and allison 6 speed that has been sitting for 2yrs. Here is the backstory, bought coach 2yrs ago and had overheating issues. Ended up blowing a head gasket. Coach was towed to thw spot it is sitting at now. It was towed improperly from what im hearing. Coach was towed about 10 miles without removing axles or driveshaft due to fact the tow truck driver could not get them out on side of road. So it was towed to his shop where he took driver axle out and said that is all that was needed. Then towed it 25 miles to where it has been stored until now. I just got the new head gasket on and got it running. I have put axle back in and with it idling in neutral or drive or reverse the driveshaft spins to the differential but coach doesnt move. There is a bad air leak which i havent been able to get under it to try and fix. It is only making 20ish lbs of air pressure. My question is, does the air system have anything to do with the differential not spinning or locking up. I cant believe that driveshaft should be spinning like that but im very much hoping that the low almost non existent air is the problem and that something rear or trans isnt broken. Anyone that has experience with these id love opinions. Its sitting on muddy gravel so its going to be a chore to get under it and figure this air leak out. Thanks for any ideas as to how this works.

jeepfreak · 11-19-2015, 04:32 PM

It sounds to me like the other axle is missing or broken. Are you sure the axle you put in is bolted to the hub? It really sounds like an axle shaft issue. Are there any grinding noises? It is possible that the ring gear or pinion gear could have some teeth stripped off , but I think there would be some serious noise. Double check the axle shafts.

twinboat · 11-19-2015, 04:38 PM

You may have the axles swapped. Is the center of the diff. offset. Did the axle engage in the splines.

ChasA · 11-19-2015, 04:45 PM

Air brakes will lock up when air pressure is below 40-45 psi. Fix your air problem first. After that, your brakes may still be locked from sitting for 2 years. They usually break loose easier in reverse.

mustang guy · 11-19-2015, 05:48 PM

Axles are in it correct. And i understand the airbrakes are not disengaging but how can the driveshaft spin if the differential(wheels) are stationary. Im wandering if there is some type of air actuator on the differential that engages it. Anyone know?

twinboat · 11-19-2015, 06:00 PM

40 years of heavy equipment and heavy trucks. The only thing I recall that could disconnect, intentionally, was the 2 speed diff. I'm sure you don't have one.

If the axles are in the splines and hub studs, something is broke inside. The brakes have nothing to do with the gears inside the differential. I am guessing that towing it, with one axle in, could have blown the spider gears.

Pull the drain plug and look for steal chunks.

alank · 11-19-2015, 06:49 PM

I'm with twinboat, spider gears don't normally spin, the whole spider gear assembly just rotates in the center of the ring gear. If one axle was out, one axle was in, the "in" axle would spin the spider gears because there would be less turning resistance in the spiders than turning the whole ring & pinion and drive shaft. The real killer might be that the spider gears were not down in the differential oil supply where the ring gear runs, and had no lubrication while the coach was being towed.

FunGus · 11-19-2015, 07:28 PM

I am guessing that towing it with one axle still in allowed the differential to turn and the spyder gear that was not held in place by the other axle has slipped out of place and is the bottom of the carrier or differential housing. Now the second axle has been reinstalled, but it was not able to engage the spyder gear that was not in the proper place.

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mustang guy · 11-19-2015, 08:08 PM

That makes perfect sense to me. Do i even want to know how big of a pain it is to work on the diff in this thing? Lol

slickest1 · 11-19-2015, 08:12 PM

I agree with Twinboat. I would drain the oil out of the diff and look for debris first. The air leak could be something disconnected that the tow truck hooked up to to release the park brake.

FunGus · 11-19-2015, 08:52 PM

Quote:

Originally Posted by mustang guy

That makes perfect sense to me. Do i even want to know how big of a pain it is to work on the diff in this thing? Lol

No, I don't think you want to know that

All of them that I have seen on the pushers are similar to an old ford 9" front load- there is no diff cover to remove because is all goes together with the front (rear on pusher) cover that houses the pinion.

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Poohbear7278 · 11-20-2015, 04:28 AM

Not hard to work on , but a little heavy to handle and takes a little knowledge to set the backlash on the gears

NHRA225 · 11-20-2015, 05:58 AM

Quote:

Originally Posted by twinboat

40 years of heavy equipment and heavy trucks. The only thing I recall that could disconnect, intentionally, was the 2 speed diff. I'm sure you don't have one.

If the axles are in the splines and hub studs, something is broke inside. The brakes have nothing to do with the gears inside the differential. I am guessing that towing it, with one axle in, could have blown the spider gears.

Pull the drain plug and look for steal chunks.

Then determine which Rear End You have- Most have Eaton's there is a data plate on the Housing- Call them and ask your questions. I would not put it in drive until you repair it. In addition that's not a Driveway repair. Way too Heavy to deal with.
For Future Reference the Axles don't need to be removed for towing-Just the Drive Shaft !

twinboat · 11-21-2015, 01:47 PM

Having driven trucks with frozen, empty air systems, into the shop, by standing on the throttle and overpowering the parking brakes, I would suggest that that's not what happened.

It takes high heat or extreme impact to bust spider gears.