Coach won't move when in Gear - 03' Beaver Santiam

[khannah42]

Hello fellow coach owners.

I have an 03' Beaver Santiam that I drove about 45 miles, parked it and sat for 35 days and now I start it up and it won't move when I put it in Gear.

The coach starts, shifts into D and R, engages into gear but she won't move. I put the coach into Neutral and tried to pull it any distance with my 1 ton diesel and it wouldn't budge.

What I have done so far:

a) Checked the Transmission fluid level. It has an Allison tranny and when I pressed UP/DOWN simultaneously it did not give me a code for fluid level. I checked the dipstick when it was running and it was below the OK level so I added a quart, checked it again and added another quart.

b) Took a hammer and pounded on the backside of both rear wheels to free up the brakes in event they were rusted / stuck to the brake rotors. When pressing up and down on the brake and park brake you can hear Air pressure releasing and activating.

At this stage it feels like a brake issue. The coach wants to move when in gear.

Any ideas? Thanks.

[RayJr]

My uneducated opinion the brakes are stuck/frozen I would try rocking it back and forth. It does air up? Right?? Good luck.

[twinboat]

If you believe the shoes are rusted to the drums, you need to strike the brake shoes WITH the parking brake OFF.
Be sure to chock the wheels.

If you have disk brakes, look on the drive shaft for a parking brake.

[khannah42]

Well now appears I have a bigger problem.

I had a local mechanic meet me to look at it and put too much throttle while in reverse to try and get it unstuck. The pinion is now broke.

[Unplanned]

I was just going to say Don't give it too much throttle!
Same thing happened to a friend of ours.

[twinboat]

The pinion was probably the cause of your problem in the first place. Probably jammed against the ring gear.

A good rear diff. can take more thrust then you likely applied.

Your engine needs to be held at full throttle for a long time before it gets the boost pressures up to develop high HP and torque.

Stall speed tests, of torque converters, are tested that way often.

[Unplanned]

Originally Posted by twinboat

The pinion was probably the cause of your problem in the first place. Probably jammed against the ring gear.

A good rear diff. can take more thrust then you likely applied.

Your engine needs to be held at full throttle for a long time before it gets the boost pressures up to develop high HP and torque.

Stall speed tests, of torque converters, are tested that way often.

I have to respectfully disagree with you. I have seen it happen personally.
It's the forward to reverse action that does it. Diff gears are OK with lots of torque applied in the forward direction, but all bets are off in reverse.
I have had lots of customers with broken diff gears happening when backing in deep mud and it starts to hop.
40 years in the business and you see a lot.
Happy Glamping.

[twinboat]

Originally Posted by Unplanned

I have to respectfully disagree with you. I have seen it happen personally.
It's the forward to reverse action that does it. Diff gears are OK with lots of torque applied in the forward direction, but all bets are off in reverse.
I have had lots of customers with broken diff gears happening when backing in deep mud and it starts to hop.
40 years in the business and you see a lot.
Happy Glamping.

We agree to disagree.

Being involved for 35 years in municipal snow plowing and land fill dumping, with lots of backing, blown differentials were a rarity.

I think the short, often ungreased, drive shaft and ever changing ride height may be vibrating the pinion bearing apart.

[PlanBee]

Ring and pinions are the most vulnerable in reverse, As a technician in another life I have seen quite a few broken and almost always from pulling in reverse.

[twinboat]

I suppose time will tell if its a bad transmission and he blew the rear OR was a seized pinion, but now a blown rear differential.

OP, please follow up on your repairs.

[barmcd]

I had to replace the ring and pinion gear and yoke on my coach . I have no idea how it happened as I hadn't owned it very long. The first estimate was $1600 for the ring and pinion, then they found the yoke was bad and I paid an additional $600 or so for the yoke and one u-joint.

[Unplanned]

Originally Posted by barmcd

I had to replace the ring and pinion gear and yoke on my coach . I have no idea how it happened as I hadn't owned it very long. The first estimate was $1600 for the ring and pinion, then they found the yoke was bad and I paid an additional $600 or so for the yoke and one u-joint.

So you had 2 failures.
Often the yoke is worn to a point where the u-joint cups are loose in the ears. They probably found that when they took the drive line off.
I spent many years rebuilding transport truck diffs and transmissions.
Before the days of semi annual inspections, failed u-joints from excessive wear was common. Now they are checked every 6 months in BC. It's not unusual to find a worn/loose yoke on some of the older trucks.
khannah42's failure sounds like a shock load. Too bad there isn't any pictures. Easy to tell then.
Happy Glamping.

[RobRoy]

Originally Posted by twinboat

The pinion was probably the cause of your problem in the first place. Probably jammed against the ring gear.

A good rear diff. can take more thrust then you likely applied.

Your engine needs to be held at full throttle for a long time before it gets the boost pressures up to develop high HP and torque.

Stall speed tests, of torque converters, are tested that way often.

I think you on the right scent


I've seen pinion bearings so bad on 9 Fords that the vehicle wouldn't move because the pinion could then cock so bad it would climb the ring gear and lock up tight.



As stated you have stated I can't imagine how you could build enough power to snap the pinion .... you cant neutral slam the trans ( wont go into gear to do so) and as you have stated you should be able to stall the converter with no problem other than excessive tranny temps from overdoing so.

[khannah42]

Yes I will update on progress. I would post pictures but there isn't much visible where you could see a problem.