Locked-up rear end
 

Went to help a Model A owner who has a major problem. The car won't move in any gear to the point of stalling the motor. Tranmission is in good shape. Before we go to remove the rear end for repair, Is there a way to tell if the problem is ring/pinion vs spider gears?

Re: Locked-up rear end
 

Put the rear end up on jack stands, put the tranny in gear, then turn one rear wheel by hand and see if the other rear wheel turns the opposite direction. It should turn smoothly without clunking and binding. If it does, then the spider gears are likely good.

BTW, I've seen brake lining bind up a rear end.

Does the gear shift feel normal as you move it through each gear?

Re: Locked-up rear end
 

If the spyders were locked, car would still roll straight forward. I'm betting the trans is stuck in two gears. Just a guess really. Does the car move in reverse with shift lever in nuetral? It's time to remove the rer and trouble shoot.

Re: Locked-up rear end
 

I had an E-brake so mangled it would not release.

Re: Locked-up rear end
 

Trans seems to shift smoothly through all gears. In 1st gear, it might move forward inch or two. Same thing in Reverse. Then with trans out of gear, will not roll in either direction.

Re: Locked-up rear end
 

Do what Tom says and put the rear end up on jack stands. Then try to spin the rear wheels on each side with the trans out of gear. If one will turn and not the other then one of the wheels is locked up. If neither will turn it could be the rear end. To get them to spin you might have to back off the brake adjustment wedges, but before you drive the car make sure they are adjusted back up.

Jerry

Re: Locked-up rear end
 

Raised rear and both wheels/axles rotate as they should. Ring pinion problem? U-joint?

Re: Locked-up rear end
 

At this point I'd make sure the tranny isn't locked in two gears at the same time. You should be able to tell by the feel of the gear shift lever as it moves the gears, but you may want to remove the top of the tranny to be sure. This will also give you a chance to see if the problem could be in the tranny.

The engine runs OK as I recall, but I found a bolt in the bellhousing locking the flywheel from turning once.

BTW, how did this problem originate?

Re: Locked-up rear end
 

did this come on suddenly?
What was done to the car before this happened.
Did the owner drive over some RR tracks too fast? With wheel hop you can destroy the pinion if you do so.
How do we know the tranny is good? Did it work OK before the wheels locked?

Way more info is needed; this would be an unusual problem.

Re: Locked-up rear end
 

I agree with Tom's assessment. To eliminate any e brake issues remove the drums and check rotation then .
Larry

Re: Locked-up rear end
 

Came on suddenly. Car is driven frequently. Owner reported hearing a "clunk" upon leaving a stop light. With floor jack under banjo, wheels rotate freely. Makes me think there is not a brake problem.

Re: Locked-up rear end
 

In reply 7, "they rotate as they should". In other words, rotate one side forward and other side rotates backward? Can both be rotated forward or backward with a person on each wheel and transmission in neutral? Success on these test should eliminate a differential and driveshaft problem.

Re: Locked-up rear end
 

Will the wheels roll if pushing the car in neutral?

Re: Locked-up rear end
 

Look at the ring gear through the fill hole..

Re: Locked-up rear end
 

My 29 Special Coupe was trying to lock up when coasting, on acceleration it would pull with no problem but was making noise. When I disassembled rear I found the pinion bearing preload and lock nuts had come loose and traveled up drive shaft. I had to build rear with new ring gear and pinion, bearings and gaskets. The old ring and pinion looked ok but was a 4-11 ratio, I put in 3-54 and am very pleased. Dwayne

Re: Locked-up rear end
 

Re: Locked-up rear end
 

I think before you do that< you should pull the trans tower. As tom mentioned, much easier job. pete

Re: Locked-up rear end
 

Did you peak in the fill hole??

Re: Locked-up rear end
 

Trans tower was removed and trans drained. No damaged gears. All seems to be in order. Every gear shifts as it should. Have not looked in the fill hole of rear end.
1. When clutch released, stalls engine, doesn't move.
2. With trans in nuetral, will not roll.
3. With rear wheels off ground, both wheels turn freely, in opposite direction as they should.
4. With rear wheels off ground, trans in nuetral, attempt to rotate both wheels same direction was not possible.

Re: Locked-up rear end
 

Look for metal in the diff oil when u drain it. If you see none or nothing when looking in the fill hole ,,, open the clamshell first when you go to drop the rear...

Re: Locked-up rear end
 

That's my plan. I'm hoping for a u-joint fatality.

Re: Locked-up rear end
 

If you don't find any problem at the clamshell, then you can remove the right brake drum and left side axle tube bolts, and pull the axle assembly out the left side.

Re: Locked-up rear end
 

I agree with Tom but I think it's almost best to undo the clamshell and pull the rear axle back a little . you can then use a pair of channel lock pliers to tey and turn the driveshaft, you can complete removing the rear axle further back to access the left side housing easier to remove and also check out the u-joint and driveshaft. It's possible you have a pinion bearing issue , u torque tube/houaings and hopefully not a gear issue. Your spiders and axles appear to be ok as you turned them both in opposing directions ok .
Let us know. Best of luck!!
Larry Shepard

Re: Locked-up rear end
 

We had the very same thing happen in my shop last summer. One of the driveshaft bearings had disintegrated, and the small rollers were locking up the ring gear. I'll bet that is what you will find when the rear is disassembled. Car was driving down the roadway, and suddenly just locked up.

Re: Locked-up rear end
 

My efforts will now have to wait until Saturday. Delayed by good weather!

Re: Locked-up rear end
 

I had a problem with the same symptom in a '30 CCPU I once owned. The bearing in the torque tube (near the U joint) came apart and the rollers jammed between the drive shaft and the inside of the torque tube.
Transmission would shift, but letting the clutch out would stall the engine. The rear wheels were locked up.
Remove the rear end and check torque tube before cracking open the differential.

Re: Locked-up rear end
 

UPDATE! Returned today to lower/roll out rear end assembly. We found catastrophic failure of universal joint. Easy fix, back on the road this afternoon. Check out the photos.
Thanks for all of the responses!

Re: Locked-up rear end
 

You sure did luck out.

Is this what happens when you don't pack the cavity full of Mystik JT-6 High Temp grease? :D

Re: Locked-up rear end
 

Wow you got to quit dumping the clutch when your leaving tree at the drag strip !! :-)

Re: Locked-up rear end
 

Thanks for the update ... That's good news

Re: Locked-up rear end
 

I installed a Mitchell O/D in my 1930 Model A and I noticed that the rear wheels will not move now (the service brakes are not engaged nor is the emergency brake). Pulled the drums to verify brake linings were not binding on the drums. Both sides are stuck.

With the car up on jack stands front and back, I placed the car in 3rd and the Mitchell O/D in LOW to see if I turned the engine the rear wheels would move but couldn't get it to budge by hand. I tried the car and O/D both in NEUTRAL too to see if I could spin the rear end but that didn't work either.

Curious if there is some binding at the ring and pinion and if I shouldn't start the car and engage the gears?

I noticed that you need special tools and presses, etc. to perform a rear-end rebuild. I own the puller kit, but not all of the special tools necessary to repair the rear end.

Thoughts on why the installation of the O/D would lead to the rear end locking up? Doesn't make sense.

Re: Locked-up rear end
 

Pull the tower first