Sudden Lock Up

[Marshall V. Daut]

I didn't see it mentioned so far, but a super easy way to tell if a tooth has broken off the ring gear is to remove the top oil filler plug in the differential center housing. This will give you access to the ring gear. Take a small flashlight and a long screwdriver and with the transmission in neutral, use the screwdriver to step the ring gear through its path, one tooth at a time. Mark the first tooth with a light-colored spray paint or White-Out so that you know you have already checked that tooth. If a tooth has broken off, you will see and feel it as its turn comes before the open filler plug hole. It's more likely that a ring gear tooth has broken off than a tooth from the pinion gear. If you find a chipped or missing tooth, you'll know what needs to be done.
On the other hand, should no tooth be broken or chipped, a differential gear (spider gear) may be frozen on its shaft. This is rare, but can happen, especially if the rear end lube level was low or the wrong kind of lube was used. Possibly water damage over the years started the process of rusting shafts. I have only seen this happen once in my Model A years and that was because the lube in the rear end had leaked out and the moving parts inside the differential ran dry.
The only other thing I can think of that could have caused this problem would be a loose pinion bearing. If that happened, you'd feel a vibration upon decelerating because the driveshaft would be wobbling against the ring gear. If allowed to continue and progressively get looser, the heavier pinion gear will eventually shear ring gear teeth and/or jam and lock up against the ring gear.
Let's hope for your sake (and your wallet's!) that none of these scenarios comes to pass!
Marshall

[Marshall V. Daut]

My advice above, of course, will only help if you can turn the ring gear. If it's locked up and won't allow itself to be turned by a screwdriver between the teeth, the rear end has to come apart anyway.

[jg61hawk]

Thanks for the advice. I removed the drain plugs. The car is on jack stands so I could turn the rear wheels and watch inside. Did not see any teeth broken on ring gear. Heard nothing strange. I did see damage (see pictures). There were chips on, the flange area of the ring gear...not sure I described that correctly. Hopefully the pictures are clear. I also filled the rear with kerosene and spun the wheels and drained it...no pieces. I took a magnetic pick up tool in both drain holes...nothing substantial.

[Jerry Kzoo]

With the trans in neutral see if both rear wheels will spin at the same time in the same direction. That will tell if the jam is in the differential. You might have sheared off a axle key and the one side was spinning inside the hub??

[johnneilson]

There is damage to the ring gear minor diameter edges, it needs come apart

suspect pinion gear problems

best of luck, J

[jg61hawk]

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With the trans in neutral see if both rear wheels will spin at the same time in the same direction. That will tell if the jam is in the differential. You might have sheared off a axle key and the one side was spinning inside the hub??

The car is on jack stands in neutral both wheels can spin in same and opposite direction...I don't know what that means but it appears you do...HELP!

[Phil Brown]

Yea no need to waste your time looking through that little oil hole that one pic shows something hit the gear carrier and the gear.it needs to come apart
Unless you want to just see how far it can go as it self destructs

[Synchro909]

The wheel turning in opposite directions like that is quite normal.
If a tooth were to part company, it is usually from the pinion. About the only way to have a look at that without taking everything apart is with a fibre-optic camera. Even then, it would be difficult.

[johnneilson]

You could wait until it looks like this... it only went 7 miles

John

[Arkomo]

You know my friend had his rear axle start doing some very loud popping. It turned out that he had a piece of one of the spur gears broke out and was getting caught between the ring gear and the diff case. Even cracked the banjo. Had to rebuild the whole thing.
You could have something like that or possibly a bearing was the culprit. Never the less, I bet you will need to take the diff apart. Tom

[Randall]

U joint

[J Franklin]

Originally Posted by Randall

U joint

Gotta ask how that computes?

[Randall]

if u joint has broken it can lock wheel,I had one to break on my T going to Ohio and it slide tires,the pieces can float around and then go back in place letting drive shaft turn again ,would check before I took diff.apart,also wondering if nuts that hold pinion bearing has backed off

[Phil Brown]

Originally Posted by Randall

U joint

I can see that happening, but he already said that when he drained the oil there was a lot if metalic mixed with it so there are most likely still problems in the rear.
But if it is a bad u-joint he will see that as soon as the rear axel is separated from the trans clamshell

[nkaminar]

Could be both. In any case the rear end will have to come apart. Sorry.

[stevemclark]

If you need a new ring and pinion ,Pinion 9 Teeth - Ring 34 Teeth - Standard 3:78 to 1,now is the time to consider if you want to go with a higher ratio,Pinion 11 Teeth - Ring 36 Teeth -3:25:1 High Speed( actually it's 3:27:1) a 13.5% increase in speed, 45mph=58.5mph,50mph=63mph estimated , but 1st and 2nd gears are higher too.You will need to change the speedometer driven gear as well , that is very easy to do.Some venders have these ,Mikes has both,check to see who ever you go with has them in stock as well as the speedometer gear if you change ratio.It's cheaper than overdrive. I have thought about this but living in the mountains overdrive would be it for me.

[Gene F]

Originally Posted by stevemclark

If you need a new ring and pinion ,Pinion 9 Teeth - Ring 34 Teeth - Standard 3:78 to 1,now is the time to consider if you want to go with a higher ratio,Pinion 11 Teeth - Ring 36 Teeth -3:25:1 High Speed( actually it's 3:27:1) a 13.5% increase in speed, 45mph=58.5mph,50mph=63mph estimated , but 1st and 2nd gears are higher too.You will need to change the speedometer driven gear as well , that is very easy to do.Some venders have these ,Mikes has both,check to see who ever you go with has them in stock as well as the speedometer gear if you change ratio.It's cheaper than overdrive. I have thought about this but living in the mountains overdrive would be it for me.

Steve, that is interesting, because I was a at a car meet and a guy told me he would not install the S-10 transmission again. Said it was a lot of work, and you don't pick up that much...

[jg61hawk]

So here's the update. I drained the trans too...actually big stuff showed up in the cup part of the drain plug. I figure this car is in my possession for 9 years and we drove from NJ to Gettysburg and Morgantown National Meets. In 9 years I put 5,000 miles on it. Engine is perfect.
I removed the rear hubs, no brake issues that I saw. I put new keys in the axles, and torqued to 125. I bought magnetic differential drain and fill plugs. I'm going to refill all fluids and drive it locally (like I have generally always done). NO MORE long hauls until I get it professionally repaired. In NJ there are no "local" places, but Schwalms is about 200 miles away and I can handle that. They have a waiting list...but I'll see what happens. Generally if I take the car to a local diner or small car show it's done for about a month.

[Keith True]

Are you really going to drive it around? When I find pieces in a rear or trans I won't even move it two feet under power.It gets put into the garage with the forklift,wheel dollys,or off the back of the truck.Right now you might have a broken part or two,a ring,pinion,axle gear,spider gear,bearing,you wouldn't know until you open it.You might get many miles or months,but you also might get 100 feet and grenade the whole thing.I saw a 32 rear self destruct because the owner wouldn't listen to my boss.It would clunk,lock up,and free up when he backed up.Then it was good for a while.It let go less than 100 feet from his driveway,and it took both axle trumpets,the center,both axles,the carrier,and the driveshaft.

[Phil Brown]

Keep your phone handy, one to call AAA, and two, to take pictures because the destruction night be epic
Not judging your decision, just probley not the one that most of us would make