Jumping out of 2nd gear

[ozkiwi]

I have recently purchased a 1929 Phaeton that has travelled 88,000 original miles. I have found that when travelling uphill in second gear under load that she jumps out of gear. Any ideas as to a solution to the problem? Suggestion has been made to replace the gear shift plungers and spring and also to drain the gearbox and refill with 600W oil equivalent. Has any one else had a similar problem that can help me.

The transmission is smooth and noise free in all gears and the shift is precise

[BRENT in 10-uh-C]

As someone has hinted, a worn shift rail can cause this, as can a worn input shaft bearing, ...or a misaligned transmission to engine (missing flywheel housing shims). Is the transmission noisy in 2nd gear, or any vibrations? How much "play" in the shifter? Is the shift a precise H pattern, --or is making the 1 - 2 shift a slantward movement?

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[Commander Toasty]

Mine does exactly the same and is indeed nosy in 2nd gear, you can really hear the gears whining. I have tried a few different fluids with no change.

[GaryA]

I have the same problem also, and 2nd is noisy. When going up a hill in 2nd gear I keep my hand on the gear shift lever with a little pressure so it wont pop out.

[J Franklin]

The gear to main-shaft spline clearance is a critical fit and sloppyness there will also cause this.

[Tom Endy]

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There is a long shopping list of why a Model A wants to jump out of gear. Part of it is the fact the gears are straight cut as opposed to being helical. There are also a number of things internal to the transmission that can cause the problem. However, there are two easy things to address without removing the transmission from the car.

Check that the two metal spacers are inserted in the two ears of the clutch housing where it attaches to the engine block. The spacers are brass and are .010 thick. Their purpose it to properly align the housing to the drive line of the car. They should be the same thickness as the gasket installed between the housing and the block. If they are missing they can be easily installed. Bratton has them in their catalog.

Next address the transmission tower. If you have access to one from a car that does not jump out of gear, try it on your car. You can also rebuild your tower without having to pull the transmission from the car.

Tom Endy

[Commander Toasty]

(Check that the two metal spacers are inserted in the two ears of the clutch housing where it attaches to the engine block. The spacers are brass and are .010 thick. Their purpose it to properly align the housing to the drive line of the car. They should be the same thickness as the gasket installed between the housing and the block. If they are missing they can be easily installed. Bratton has them in their catalog.)

Do you have a picture or diagram of this location?

[J Franklin]

They are where the accelerator assembly are attached

[Tom Endy]

Sorry, I don't have a diagram. The shims are listed in Bratton's catalog under p\n 9120, page 41. The catalog shows a picture of them. The shims are horse shoe shapped. They go on each side of the rear of the engine block. Loosen the two bolts that hold the accelerator linkage to the engine. Use a pry bar to open a gap where the ear of the clutch housing attaches to the block. Drop the shim in from the top. To check if they are there wipe the ears clean and you should be able to see the top edge of the brass shim if it is there.

Tom Endy

[Karl]

Wow that was quick -you must have gone home from car club and posted on the forum. As predicted they're a helpful bunch (even if they are confused about the correct side to put the steering wheel on) If you need access to the Brattons catalog as suggested previously I have one (plus ones for all the other major parts houses). Have found the service from the States excellent and even allowing for postage/exchange rates very competitive regards pricing . I also have a spare transmision tower on top of my spare gearbox -Condition unknown . Hope to see you on Sunday -Karl

[steve s]

When my car did that many years ago, I had to forcibly hold the lever in place all the way up a hill. The problem was very worn, rounded off 2nd gear teeth. The fix was another trans for $5 at the junk yard. Those were the days.

Steve

[Commander Toasty]

Tomorrow I will get the car on a lift and have a look to see if the spacers are in place. But first - a question. Generally you don't get one effect without creating another. If these spacers cause enough gap to change how things work in 2nd gear ... what else do they effect?

[Dave in Boise]

FYI on the spacers.. If you are missing them, clean out the gap as well as possible (a couple or passes through with a piece of construction paper will ofter clear out the oil and muck from the gap) and then put a *tiny* bit of rtv on the shim, so when you put it in and tighten the bolt back on, the shims will not fall out oif you ever have to dissassemble again...

[steve s]

Originally Posted by Commander Toasty

.... If these spacers cause enough gap to change how things work in 2nd gear ... what else do they effect?

My understanding is that missing spacers result in drivetrain misalignment that lead to a whole world of shifting and vibration problems. Since you only mentioned the 2nd gear problem, which exactly matches a problem I had, is why I think your problem is with the teeth on your 2nd gear. It woudn't be too hard to take off the top and have a look.

Steve

[JoeWay]

More FYI--Some people, myself included, delete the shims AND GASKET when possible, using a thin coat of RTV on the full contact area including shim points. I bolt up the housing, then sweep it with an indicator. If it can be brought into spec without a gasket, I use the RTV.

If there is NO gap at all between the ears and the block when the bolts holding the accelerator bracket are loosened, It may have been assembled this way.

Also note that gaskets vary widely in thickness. I have new housing gaskets ranging from 0.009" to 0.020", all purchased in the last few years from reputable suppliers (Bert's, Bratton's, etc.). It is not safe to assume that an installed gasket is the correct 0.010" thick.

Joe

[Peyton]

I'd replace the transmission plungers first. Easy and cheap to do. Popping out of gear going up-hill and moderate pressure on the gear shift lever to prevent popping out of gear leads me to believe your problem is either weak springs or worn plungers.

This fix worked for me.

Peyton

[Tom Endy]

I certainly agree with JoeWay. Gasket thickness is all over the map. When initially assembling the clutch housing to the block determination of the gasket thickness and the thickness of the shims should be determined. All the bolts should be torqued down to determine how true the housing fits. This includes the bolts that go through the two ears. Either temporarily install the accelerator mechanism or use shorter bolts. You only need to check the allignment of the top 180 degrees of the housing. That is from the 270 mark to the 90 mark. The bottom 180 will be pulled into alignment when the bell Housing is bolted up. Before the bell housing is attached you can grab the bottom of the clutch housing and move it back and forth.

Many clutch housings have been whacked out of shape over the years and you might not be able to get a proper alignment. In that case you have to find another. Proper alignment is important as it could affect jumping out of gear and premature clutch failure.

I believe the spec allows something like a .006 difference across the top 180 of the clutch housing

Tom Endy

[Tom from Drippin']

[QUOTE=Commander Toasty;79415]Tomorrow I will get the car on a lift QUOTE]

No need for a lift. They are the top two bolts at the top of the housing where the accelerator linkage attaches.