Locked-up rear end

Del in NE Ohio

Del in NE Ohio

Senior Member
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?
 
Put the rear end up on jack stands, put the ****** 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?
 
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.
 
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.
 
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
 
At this point I'd make sure the ****** 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 ****** to be sure. This will also give you a chance to see if the problem could be in the ******.

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?
 
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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 ****** is good? Did it work OK before the wheels locked?

Way more info is needed; this would be an unusual problem.
 
I agree with Tom's assessment. To eliminate any e brake issues remove the drums and check rotation then .
Larry
 
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.
 
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.
 
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
 
Update! Returned to the "A" in question today. With trans in nuetral, rear wheels off the ground, we each attempted to rotate rear wheels forward and then attempt to rotate to the rear. No dice. Locked up tight. So... I'll be returning on Sat AM where after consuming requisite coffee & donuts, the rear end assy is coming out!
 
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.
 
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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...
 
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