Automobile Transmission, why not?

They do have thrust bearings, but those thrust bearings are not there to do what a thrust bearing in a marine transmission is doing. Is the driveshaft in a vehicle "pushing" straight ahead against the transmission's output shaft in order to move the vehicle down the road? Of course it isn't.

Thrust bearings in an automotive transmission are there to allow sub-assemblies to stop/start/reverse direction/rotate at different speeds without tearing the adjacent sub-assemblies to bits. They are not dealing with a thrust load from the driveshaft pushing the vehicle down the road. If you think they are, you're very mistaken.

Here's an experiment for you to try if you believe otherwise:

Remove the driveshaft from your vehicle and find a suitably heavy spring to slide inside your driveshaft yoke so that the spring gets somewhat compressed as you wedge the driveshaft back in place. (The spring needs to be at least partially compressed....butting up against the output shaft on one end, and the bottom of the driveshaft yoke on the other end.) Now, with your transmission seeing a, (pretty mild really), *thrust load* against its output shaft...drive it for a while and see how long it lasts as its internals are "protected" by the OEM thrust washers inside.

Post up your results.

With pictures if possible.

 

Why would anyone not install a thrust self alining bearing on a prop shaft?

 

Have to agree with you Broke not, that other post was very silly and the part that you need a high stall converter just capped it off

 

Do it right

New Jersey clam boaters DID put the ENTIRE auto engine setup into flat bottomed workboats. Ran forever wuth no fires reported.

BUUUTTT

They took the radiator / trans oil cooler WITH THE ENGINE. Closed system with anti freeze for winter use. It was reliable as Hell. Ugly. But reliable. ALL setups used the original transmission oil metal tubes.

They ALL used a BIG self aligning thrust bearing braced between 4 of the frames.

Pratical & cheap.

They should meet all USCG requirements as ALL gasoline components were exposed to airflow. So was the radiator fan blade to people.

Can I do it safely today. Yes.

Could you? Maybe.

 

how about a photo

 

The probs waith a auto tranny from a car would not be installation but opertaion hydraulics. Yes you needa thrust bearing, lets just get that out of the way.

1st gear is very low and is not really much good. There are external valve block kits that would operate it but I dont know of a marine converstion valve block.

An auto tranny in a car is one long lump of clutches and band hubs. The line pressure is split into 2, it opposes governor pressure to throttle pressure to change gear. There is also modulator valve that increase band and clucth operating pressure for kick down etc that you will be needing 100% of the time due to a boat needing max torque transmission all the time. If your modulator isnt working on a car it would slip on kick down.

( its a vacuum operated valve on the outside that reads vacuum from the manifold) Plus kick down adjustment on the throttle cable.

Without a specialized valve body a slow pull out woud not apply modulator pressure and would slip almost imediately. Its doable but its going to need some serious hydraulic mods and only 2 gears and reverse would be needed.

I suppose if you locked 1-2 shift valve and locked the modulator, and used only2-3 shift valve on a three speed you might get something.

EDIT

Ive just thought about the governor pressure, phew lot of work.

 

completely wrong frosty, i have seen a dozen c4 autos stock standard in boats that work well.

 

Your right Frosty
Art Carr has been selling autos ( pretty much as you described) modified for boats in the US for 40 years
I have read many tests over the years as many went into production boats
( without torque converters)

 

what kind of boats?
you mean with torque converters as well????
I dont think so???

 

Not without a lot of mods.

You just 'have' to boost that modulator pressure even if you keep your 123.

In a car max modulator would be like someone driving up the back of you everytime it changed gear but in a boat it would be necessary.

I assume you would be doing this to get the boat out of the hole with a big prop, then you would aslo need to set the gear change speed, which in auto mode is when governor pressure overcomes throttle and shifts the 2to3 shift valve. On a boat this is the only gear change you would need.
This would need to be manualy selected meaning if an auto tranny was in a boat some serious valve body work is required.

And if you did that some of the epicyclic gears could be removed and the torque convertor removed.

Might as well buy the proper one.

Yes it may LOOK like a c4

 

yes i do mean with convertors, completely stock. ford c4 and c6 autos work good. i have mentioned all this at the start of this thread. snowy day is the bloke who fits them to his boats, has done for years. his current boat is a 30 ft atkins design with a 4 liter ford 6 and borgwarner auto. all his boats have been warped hull pre 50's designs around 28 - 32 ft. easily driven boats which perform well. i remember 1 which had a 302 cleveland with c4 and it cruised at 25 knots. i am not making this up, i have driven these things .

 

powerglide 2 speed autos were sold here for boats, they had the convertor removed and the extension housing replaced with a thrust bearing and shaft coupling.

 

Were they the ones from Frankston?
if so they were supplied as single speed and took a lot of work to get them to work but never solved the prop turning whist in neutral problem last time I checked
at AUD 75 cents to USD it worked but at 1:1 no chance

You just can beat a marine tranny, the market has clearly spoken
Guys tried it with unlimited money on offshore boats and all have given up to either full custom made or production.
When multispeed were legal in class 1 offshore they used Weisman and Zf etc boxes, I'll bet no-one used a car box.
Velvet drive have new direct drive box out and have left them all in the dust
2500lbft at 6500 rpm, aluminium dry sump case

 

yes , they were made by robbies. i agree marine trans are the best by far but all i am saying is an auto works in a boat.

 

I cant imagine what must happen if they were installed unmodified and with the torque converter?