gregchrysler

1949 tranny bucks and not much power

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Hi there again      i just fixed the motor  advance was stuck  runs great now but when I put it in gear it bucks ?clutch not grabbing right?  and I have to rev engine to move forward

The car is a 1949 Chrysler royal   fluidmatic  just had tranny redone  costs $3000  bu I don't think i have enough power to make it up a hill     used hydraulic tractor atf tranny fluid    

tag says use 10 weight    could this cause it?    Thanks for your help as always

 

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6 minutes ago, Taylormade said:

As far as I know, these units take 10w oil, not tranny fluid.

You mean SAE 10? or SAE 10W?

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Tractor fluid, TDH type, ISO32 or ISO22 grade is a good substitute for the original fluid or for 10 oil. Whatever you use must be thin, the thinner the better. Thick oil will not work as well.

 

I am still trying to imagine how you could make the transmission buck. Maybe if you push the gas pedal to the floor boards and dump the clutch. Is that what you are doing?

 

Is there any way you can get a video? The still pictures don't show any bucking.

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Tranny bucks when I first take off and  engage clutch with engine revving for a few seconds then ok after ==it's only on takeoff ==reverse works fine  --could  a short in the governor or solenoid do this?  I will get a video tomorrow .   Thanks again rusty

 

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Sounds like oil on clutch and or a worn out clutch.  Was a new clutch installed with the transmission overhaul?

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You don't need to rev up the engine. Proper technique is to release the clutch fully with the car in gear, then step on the gas and drive away like an automatic. It is really more like an automatic that needs a clutch pedal to shift. Also you have to lift off the gas for a couple of seconds when you get up to 14MPH or more, so the trans can shift. It won't shift up as long as you keep your foot on the gas.

 

If you have to rev the hell out of it to prevent stalling that is not a transmission problem. That is an engine problem.

 

If it won't take off without stalling start by doing a compression test. If the compression is bad and your engine is shot to hell you need to fix that first. If it has good compression and oil pressure then the engine is in decent shape, you need a tuneup. What exactly is wrong I don't know. You, or a good mechanic will have to go over the ignition system and see that you are getting a good spark and that it is happening at the right time.

 

Only then do you go to work on the carburetor. It may need an overhaul, or maybe just a few adjustments. Don't overlook the choke, if the stalling is when the engine is cold the choke could be the cause.

 

All this means you need a good mechanic who knows the old Chryslers, and a factory manual so he knows what to do.

 

Guess work and hit or miss methods will only get into a deeper mess. You have to know what you are doing and make everything the way the factory meant it to be. Don't let anybody go getting ideas of their own.

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If your car is running right it will be very smooth and quiet and will have plenty of power for all normal driving. They were specifically designed to be as smooth as possible with power and performance secondary. That means they are no threat in a drag race but will take you anyplace you want to go, in comfort, from coast to coast and from Death Valley to the top of the Rocky Mountains.

 

If it runs like a sack of shit, something is wrong. It is no use saying "the transmission bucks" while forgetting to mention that you are stomping the gas to the floor then dumping the clutch. The transmission is specifically designed not to buck, in fact it is almost impossible to make it buck. I did say "almost".

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Thanks rusty   engine runs really smooth  do you know how much vacuum should be at carb?  I will try sending u a few videos today  also  reverse works well so maybe not clutch?

but power gear or first gear car hardly moves   thanks rusty u are very very helpful

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Greg I am glad to be of help. But I still don't know what the problems is. I have been working with those transmissions for more than 30 years, had them apart, studied all the literature I can find and I can't figure out any way for one to buck. Like I said the only way I can figure out to MAKE one buck, is to stomp the gas pedal to the floor, rev the engine to 5000 RPMs and dump the clutch.

 

If I am missing something it is because these haiku of yours don't give me much information to work with. That is why I suggested making a video.

 

Now you say it hardly moves. That is fairly typical, they take off slowly but soon build up momentum. Especially on soft ground or on an up hill slope you have to give it some gas to get moving. This is AFTER releasing the clutch COMPLETELY with the engine idling and the car in gear. In other words you release the clutch completely, with the car stopped,  then step on the gas and drive away like an automatic. If you try to rev it up and slip the clutch like a manual trans you will get no place or take off like a snail.

 

 

Edited by Rusty_OToole (see edit history)

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Thanks  rusty   youre a genius     I put it in gear and let the clutch up and then gave it gas --no bucking   thanks  it does take off slow but a lot better than before   I owe u a steak dinner

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Now you know the secret, it drives like an automatic and you don't use the clutch except to shift. Then drive like an automatic.

If you ever saw the clutch out of the car you would baby it. It is only about 6"  in diameter, about half the size of a regular clutch. You are not supposed to use it the way you would on a manual trans car.

 

I could never convince my old man of that. He insisted on shifting into gear, revving up, and slowly releasing the clutch. When the car didn't move he would rev it harder and slip the clutch more. Then rev harder and slip more. The car would slowly start moving and after about 50 feet he would let up the clutch pedal completely. No matter how many times I demonstrated the right method he would never listen. It took less than a year to burn the clutch to a crisp.

 

Here is how I do it. Start off parked, with the hand brake on. Start engine and warm it up until it will idle down. Factory recommendation is 450RPM idle. This seems impossibly slow if you are used to today's cars but is correct. In fact, the trans won't shift if the idle is set too high.

 

Now your motor is warmed up and you are ready to go. Step on the clutch, shift into High and release the clutch fully without touching the handbrake. Now release the handbrake step on the gas and away you go.

 

When you get up to 14MPH lift off the gas. You should hear a soft *click-clack* from under the floor boards and when you step on the gas you are in high gear and ready to go places.

 

If you come to a stop sign no need to touch the clutch. Slow down and stop like you would with any automatic. Take off when you are ready, lift off at 14MPH etc.

 

You only need the clutch pedal to shift into gear, or from forward into reverse or from Low to High range.

 

Low range, you only need that when driving slow in snow, sand or mud. Or for taking off with a heavy load or up hill. Normally you can do all your driving in High range.

 

If you do need Low range start off as you would in High range. When you get to 6MPH you can lift off the gas and it will shift up. If you want to go into High range you can use the clutch to shift as if it was a standard transmission.

 

Hope this clears things up.

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