Clutch / Torque Converter: 1952 Land Cruiser stalls with a big clunk (Torque Converter)

[aenthal]

I have been involved with old cars all of my life so I am familiar with 50's and 60's cars stalling out when they stop. Usually means a dirty carb, not warmed up, or bad timing. Carbureted cars do that, which is why later ones are fuel injected.
But this was different than anything an old car had done to me.
I took my 1952 Land Cruiser to a Los Angeles chapter meeting this afternoon. It drove there, about 20 miles from my house, with no problems. I stopped at a supermarket on the way back home. Again, no problems. Then I got on the freeway and drove home, which I expected to also involve no problems.
But when I got to the top of the freeway off ramp by my house, it stalled out with a clunk because the light at the top of the ramp was red.
Started right back up with no effort. Drove to the next traffic light, where it clunked out again. Started it back up again.
Clunked out at the corner of my street.
Started it again and semi floored it when I got to my driveway because it was threatening another stall.
It did not stall out when I stepped on the brake once it was on my driveway. Put it in park (it is an automatic transmission) and shut off the ignition normally. No clunk.
What in heck is the clunk that stalls it out?
Never had that before. Sounds like a transmission clunking. I will check the fluid level when I have some fluid with me, in case it is low.
Never had a transmission stall out an engine. Low fluid makes a temporary pass through neutral, not a stall out (at least in other 50's-60's cars I've had).
So what makes a car clunk itself into a stall when you step on the brakes?
Anybody ever have a Studebaker or other car of that era, do this. I haven't!

[studegary]

The lock-up torque converter not working properly. Be sure to check the fluid "by the book".

[StudeRich]

Yes it DOES sound like a problem with the Lockup Torque Converter in your Detroit Gear DG200.

[aenthal]

Good. A new torque converter costs way less than a transmission overhaul.

What "book" do I read that is different than the usual check the trans fluid procedure?
The instructions I just read on line seem to require two people to do this.
It says to have the car running in DRIVE, not neutral (with your foot on the brake).
That seems to imply one person is in the driver seat keeping the car under control, and the second is on the passenger side, handling the dipstick.
Maybe an experienced mechanic in 1952 was used to that, but I wasn't even born in 1952. And I sure don't trust THAT car's parking brake to keep it still if my foot slipped.
Oh well, thanks. Guess I will take it to my mechanic for the fluid check, not check it before I call him.

[RadioRoy]

@aenthal

I can hear your frustration, but it's too soon to come to any conclusions. It's better to make some checks first. The fact that the car has been driving OK means that the current trouble might be simple to fix.

In addition to the parking brake...

You could just block several of the wheels (in both directions) with something significantly sized and firmly planted. The car must be level. Idle speed must be correct.

There is no need to take it to a mechanic just to check the fluid.

If you think about it, you can come up with better ways to do things. The first idea that comes to mind is not always the best solution.

[RadioRoy]

Torque converters have an inherent slippage The input shaft turns faster than the output shaft. That's what allows the car to sit at a stop light with the engine running, but with the wheels stopped.

Studebaker fitted their new automatic transmission with a locking torque converter. When the car gets up to a certain speed, the torque converter "locks" so that the input RPM equals the output RPM. Studebaker touted this as a gas saving feature because there was no slippage in the torque converter.

Thirty some years later, General Motors advertising would tout their new gas saving locking torque converters as if it was a big new thing.

The problem is that sometimes the torque converter fails to "unlock" when the car comes to a stop. Just like with a manual transmission, if you come to a stop and forget to push in the clutch, the engine will stall.

I don't know what causes the failure to unlock. The transmission in my 54 has always behaved properly.

The first thing to do is check the fluid level - properly - and then go from there.

Check the throttle linkages, too, as well as the parts that go to the transmission. A missing cotter pin or a bent shaft can cause problems. The shop manual has lots of things to check. Some you can do, and some the mechanic can do. Check the motor mounts. One of them out of whack can affect the linkage to the transmission.

BTW, you need a Studebaker shop manual and the parts catalogs. Lots of stuff online is erroneous or contradictory, especially when it comes to 70 year old orphan cars.

[Mark L]

My daughter's Subaru Legacy had a transmission defect from the factory that caused the torque converter to unlock at too low a speed. If the car decelerated rapidly, the car would shudder and stall just as if it had a manual transmission that was left in high gear all the way to a stop. Even though the car was out of warranty, we were fortunate that the torque converter was replaced under a special extended warranty.

[studegary]

Do not just take it to a mechanic to check the fluid. They will most likely not do it properly.

Studebaker put out a separate booklet on the Automatic Drive. Brief summary; set the parking brake (block the wheels), let the car idle in L until engine/transmission up to temperature, check fluid - do not underfill or overfill. If you do not know what the fluid is, it may be time for a change in fluid (check every 1K miles and change every 15K miles or once per year).

[8E45E]

A weak starter solenoid will cause the same symptoms, making it stall randomly. The 'clunk' you hear could be from the firewall where its mounted, and the solenoid could be trying to open, thus breaking the circuit to the ignition system causing the engine to quit. Try the $12 fix first.

Craig

[aenthal]

Do not just take it to a mechanic to check the fluid. They will most likely not do it properly.
My mechanic is special. Just one guy, self-employed, not a whole group.
I found him back 30 years ago, when he was an early 20-something working in a gas station. I could spot the difference between him and people who go into auto mechanics because the guidance counsellor said they weren't good enough for burger flipping.
Eventually he opened his own shop.
Any mechanic who says "I know how to do that. I don't need any manual" does not get near my old cars. In the case of this guy (born in 1970, so he had to learn all about old cars from scratch, not past experience working on any), he will call me when I forget to include the shop manual for one of my oldies, asking where it is.
Years ago I told him that valve adjustments were done on my Edsel with the engine running. He was skeptical, but verified that what I said was correct, and adjusted the valves using the "insane" (and messy) engine running technique. When done, he admitted his initial skepticism, but agreed my old car info was right.
The suggestion that I use my "emergency parking brake" cinder bricks is an excellent one.
I can see putting the front tires against the curb so it can't go forward, and its bricks at the back, so it can't accidentally move back either. I could actually check the fluid all by myself with that set up!
But when I say I will take it to my mechanic, I mean with me explaining that this car's fluid is not checked in park or neutral, but done in drive, with the car running, after shifting from reverse, and me sitting behind the wheel, foot on the brake, with him pulling the dipstick.
Just dropping the car off and saying "check the trans fluid" is not my concept at all.
I am hoping-hoping-hoping it is just low on fluid.
Could be. Here is the reason why. Earlier in 2021 he had the transmission down to fix a whole lot of leaks the car had. When he put it back together the car would not hold in park. Reason was, it gets a shim, which neither of us knew about. He found out about the missing shim, put one in, and all was well--until now.
Entirely likely that he checked the fluid then, with the car idling in park, the way you do with most automatic transmissions.
If there really is a difference between the drive-check on fluid level, and the neutral-check, it may have been borderline not filled correctly all of this time.
So you have given me some real good clues.

[6hk71400]

I had a 1950 Packard standard 8 with the ultramatic with the lock up torque converter. It has the same problem and it was the lock up torque converter. I would start it and put it in gear and it would stall again. I could get moving by goosing the throttle to loosen the torque converter to glide into gear. Here in Tucson there is a Ultramatic specialist that still works on the old iron.

The DG 200 was in production 3 years when your LC was built. There were improvements over the years to the DG250 used in 1955. The BorgWarner then was used in Jaguars and other applications. It was and is a great transmission. As others have stated it sounds like the converter is locking up. See if a fluid change will help things. Since it was working before I hope a fluid change will work. Follow the procedure in the Shop Manual.

One thing that can happen is if the car is revved up over 2,500 rpms in neutral it can have problems occur. Again speaking on memory as I have not owned or driven a Detroit Gear Studebaker Automatic Drive car. I will let the experts weigh in on that

Bob Miles
My preference is to use my left leg to do the shifting

[RadioRoy]

<Entirely likely that he checked the fluid then, with the car idling in park, the way you do with most automatic transmissions.>

Not likely at all. Removing the floor mounted dipstick with the engine idling in park or neutral will cause fluid to spit out all over the floor. That's what happened the first time I tried it.

You should be able to check the fluid yourself. There are some things (particularly fluid levels) that owners must check regularly, before trouble happens. You need to learn to do those things yourself.

[Hugh]

I had exactly the same situation in my 51 Commander with the DG200 trans. Had nothing whatsoever to do with the fluid level. The Throttle linkage kick-down was loose, and would not let the trans allow the servo to unlock the lock-up torque converter. This lever and rod comes from the firewall down to the left side of the transmission rear case on top of the housing where the shifter linkage connects. If you have the hill holder, then it is a must you follow the manual instructions for first of all IDLE SPEED adjustment. Then the switch adjustment at the firewall right side of center. This MUST be done as written or you will have a maladjusted linkage, making for harsh upshifts and locking the torque converter clutch when slowing down to stops. The adjustment is very very precise, so don't give it the "close enough" for this old car, it's simply not so. I do not have my manuals in front of me, but the adjustment procedure is for idle speed of the engine, which MUST be at 500-550 rpm. This is with choke open and carb idle adjuster screw against the low idle cam part of the choke. The clunk you hear is most likely the driveshaft center bearing support cushions allowing the shaft to move slightly when shifting, down shifting and of course when the torque converter allows the trans to "lug" the engine to a stall. In my case the holes in the center driveshaft bearing support were worn just enough to allow the whole shaft to move up and down, causing the clunk. I experimented by taking the rubber bushings out of the bearing holder and wrapped a few turns of electrical tape around the rubbers, which were brand new. Seems the HOLES in the bearing holder/support were worn very slightly, tape eliminated the clunk, and I replaced the bearing holder. Hope I am not confusing, but this is very surely the cause., a very simple adjustment. But you must have the manuals, both the shop manual and the DG200 trans. Hugh

[StudeRich]

Andrea, I can say what Hugh explained very well for a Automotive Trained professional, but the "Lay" explanation is a lot simpler and easy to understand.
He very well COULD be on the right track though, in that hard to read "Book".

By the way, The Fluid is checked at not over 600 RPM in LOW Gear (L) !

Now that we know a little "History of your ownership of this Stude. I see a problem.
When your Good Mechanic had this Trans out and reinstalled it or worked on it in ANY way, did he know to look in the Shop Manual in Tune-Up or Fuel Section to setup the Carb. Linkage and THEN turn to the Detroit Gear Automatic Transmission section and read HOW to Adjust the "Throttle Pressure" on this Transmission?

You may want to print this, to properly explain it to him.

[Hugh]

If you have the car now drive it for a short distance and as you slow down in drive, if it “lugs” as if to stall, move the shift lever to neutral. If this unlocks the torque converter from lugging to a stall, then this confirms it is adjustment that is needed. Hugh