# Problem mating motor to transmission



## Caps18 (Jun 8, 2008)

Here is the motor side.

I think it is the 1/8" ring part that is preventing the shaft to go all the way in. Not the black hole part.


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## onegreenev (May 18, 2012)

What does the adaptor look like assembled without the clutch disk or pressure plate? Is that the correct pressure plate and clutch disk?


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## dougingraham (Jul 26, 2011)

There is a plastic alignment tool that you can buy or usually comes with a clutch kit that centers the clutch disc when you tighten down the pressure plate to the flywheel. This tool looks like the end of the transmission input shaft and centers itself on the pilot bearing which should be in the center of flywheel adaptor. I can't tell if there is a pilot bearing from the photo. Normally when you get the two pieces aligned you can just push them together. You should not have to force anything. The normal problems are the end of the transmission shaft hangs up on the pilot bearing or the pilot bearing seal. The motor and transmission are not lined up straight so the shaft won't go into the pilot bearing. If you force it you will ruin the pilot bearing.

I assume this is the first time you have tried to assemble this motor/adaptor/transmission together. If the flywheel/clutch/pressure plate assembly is trying to go too far into the transmission it will hit the throwout bearing which should already be fully retracted. If you push it together as far as it wants to go you can tell if it is hitting the throwout bearing. Just depress the clutch pedal slightly and as soon as you start it will push the motor out. If it is not fully mated and the throwout bearing is touching the pressure plate it could mean the throwout bearing is not on the fork correctly or the clutch mechanism is not fully retracted or it means the flywheel/pressure plate is not in the correct position relative to the end of the transmission bell housing. This could be a "Magic Number" issue if you made your own coupler and adaptor or the flywheel is not installed in the correct place. (too far out on the motor shaft.) There is sometimes a spacer ring that goes between the motor bearing and the coupler to set the correct spacing.

If you are trying to do this on the vehicle you might consider trying to assemble everything on the workbench where you can see a little better what is going on. In my case it was easier to put it all together on the bench and then lower it into the car as a single unit.

Good luck!


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## Caps18 (Jun 8, 2008)

The plastic adapter was used, and it worked. I haven't taken a measurement of the diameter of the plastic shaft to see if it is the same.

It doesn't look like the clutch disk has shifted or wasn't lined up. I had considered that as a possible problem.


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## Caps18 (Jun 8, 2008)

onegreenev said:


> What does the adaptor look like assembled without the clutch disk or pressure plate? Is that the correct pressure plate and clutch disk?


I think the real picture is on my other camera, but this should be close.

The bolt heads had to be ground down quite a bit.

The clutch disk is new, but does fit. I forgot to test fit the adapter to the transmission. It would be good to add that as a step in the process. The pressure plate is the one that came with the truck. The flywheel is too, but slightly modified.


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## Caps18 (Jun 8, 2008)

dougingraham said:


> There is a plastic alignment tool that you can buy or usually comes with a clutch kit that centers the clutch disc when you tighten down the pressure plate to the flywheel. This tool looks like the end of the transmission input shaft and centers itself on the pilot bearing which should be in the center of flywheel adaptor. I can't tell if there is a pilot bearing from the photo. Normally when you get the two pieces aligned you can just push them together. You should not have to force anything. The normal problems are the end of the transmission shaft hangs up on the pilot bearing or the pilot bearing seal. The motor and transmission are not lined up straight so the shaft won't go into the pilot bearing. If you force it you will ruin the pilot bearing.
> 
> I assume this is the first time you have tried to assemble this motor/adaptor/transmission together. If the flywheel/clutch/pressure plate assembly is trying to go too far into the transmission it will hit the throwout bearing which should already be fully retracted. If you push it together as far as it wants to go you can tell if it is hitting the throwout bearing. Just depress the clutch pedal slightly and as soon as you start it will push the motor out. If it is not fully mated and the throwout bearing is touching the pressure plate it could mean the throwout bearing is not on the fork correctly or the clutch mechanism is not fully retracted or it means the flywheel/pressure plate is not in the correct position relative to the end of the transmission bell housing. This could be a "Magic Number" issue if you made your own coupler and adaptor or the flywheel is not installed in the correct place. (too far out on the motor shaft.) There is sometimes a spacer ring that goes between the motor bearing and the coupler to set the correct spacing.
> 
> ...


It is the first time I am mating any motor to a transmission. 

The motor and adapter probably weigh 220 lbs. it is very difficult to move, even with pulleys and three people. I don't have the proper tools to be able to mate the transmission up outside of the truck and then move it in place.

I'm not sure about the clutch pedal. It should be in the correct position. We did measure the depth of the hole compared to the transmission shaft and they are the same length. It does feel like it was bottoming out, with about 2 inches more to go. That is why I am thinking that the shaft isn't going into the adapter.

I'm not sure what the pilot bearing is or where it is. I'll have to look it up.


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## dougingraham (Jul 26, 2011)

Caps18 said:


> It is the first time I am mating any motor to a transmission.
> 
> The motor and adapter probably weigh 220 lbs. it is very difficult to move, even with pulleys and three people. I don't have the proper tools to be able to mate the transmission up outside of the truck and then move it in place.


That is about what mine weighs. I had two assistants the first time and I did it myself after that. You just need to borrow the correct tools. An engine hoist or cherry picker they call it.

If you have never done this you may have to wiggle stuff a little to get it aligned if that is the only problem. You should not have to use a 3 lb sledge hammer to force a precision fit.

I am guessing the flywheel is not close enough to the motor so the throw out bearing is preventing you from pushing it all together. Make certain the coupler is all the way back against the motor (spacer if there is one.) If you had the throw out bearing out of the transmission make sure it is back on the fork in the correct place and make sure it is retracted all the way.

If you try to slide them together and the motor is not aligned the transmission input shaft will hang up on the pilot bearing. Then the splines engage and the throw out bearing will just touch the fingers on the pressure plate when it all drops home.


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## dougingraham (Jul 26, 2011)

Caps18 said:


> I'm not sure what the pilot bearing is or where it is. I'll have to look it up.


The pilot bearing is in the center of the portion of the crankshaft that the flywheel attaches to and supports the end of the transmission input shaft. They usually put this inside the coupler. This bearing is not as important in an EV because we don't idle the motor with the clutch depressed. That is the only time it would turn. When the clutch is out the transmission input shaft and the motor turn together.

Good luck!


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## dougingraham (Jul 26, 2011)

Just looked at the photo on post #5 and there is no way to move the flywheel back closer to the motor. So that is out.


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## Caps18 (Jun 8, 2008)

The hub is attached to the electric motor shaft as far as it can go as well.


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## Caps18 (Jun 8, 2008)

The motor is now attached to the transmission!

I did drill out the flywheel/motor shaft adapter hub just a little. But, the problem was caused by that hole being at the wrong angle or just not lined up right.

The OEM mounting brackets had to be modified a little too. I needed to drill them out for the 1/2", grade 9, 4.5" bolt to go into the motor ring holder. I also had to move some of the holes just a little so the bracket would line up with the existing holes in the frame. You can see I needed to temporarily remove one of the four metal rods on the motor to get the ring mount to fit.

It turned out well in the end, and I can now shift it into the different gears and the motor stops spinning by hand. But, in neutral it does still spin.


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## electro wrks (Mar 5, 2012)

Did you figure out how to incorporate the pilot bearing to support the end of the input shaft? If the input shaft is not well supported (the splines in the coupler may not offer enough support), you could have an early failure of the input shaft bearings and/or gear.

The input shaft on this kind of trans., if it's the typical front engine/rear wheel drive trans. has ~1/8" (3-4mm) of side to side movement on the end where the pilot bearing is located. The pilot bearing is required to locate the shaft near the center of that movement (usually within a few thousands of an inch). Without the support of the pilot bearing, the shaft can still flop around. The input shaft bearings could be edge loaded and/or the gear running clearance compromised (too little or too much), possibly causing an early failure.

This also assumes that the adapter plate is properly located on the trans. bell housing (so the center lines of the input shaft and the motor shaft are in line within a few thousands of a inch). Bolts alone or with shoulders and by feel are not accurate enough to locate the two. Locating dowels, or in your case, sleeves around the bolts are used by OEMs and reputable adapter plate makers to accurately locate the two. It's not easy for the average DIYer to set up a home made adapter plate without a good knowledge of how to use a dial indicator and/or how to do basic machine work.

The pilot bearing is not used as a rotational support as much as with an ICE, as DI says. But, it is still important with an electric motor to locate and support the end of the trans. input shaft.


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## Caps18 (Jun 8, 2008)

I didn't remember there being any movement in the transmission input shaft. Maybe when it is spinning at 3,000 rpm that is different though. The motor adapter plate should hold the motor and transmission in line with each other I would think. Even if there is just a little gap in the flywheel hub adapter. (I should have tested it right when I got it, but I think the opening was too small like it was for the EV rotor shaft.) Would the problem come from when I push the clutch in, that the rotational speed of the motor and transmission shafts might not be in sync? Or that the clutch disk on the end of the transmission shaft will cause it to be unbalanced and need to be supported?

I considered making a homemade adapter for about 2 seconds. This is not a homemade one, I did paint it though.


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## electro wrks (Mar 5, 2012)

The paint might have been or be a problem on the alignment sleeves. Although it looks like you got it together. The sleeves, by necessity, have tight tolerances in their mounting holes. The paint could prevent the sleeves from sliding in the mounting holes of the bell housing. You may have to remove the paint on the sleeves with lacquer thinner or carefully with a file or knife.

The big question is: did you figure out about the pilot bearing? Next time you have it apart, grasp the input shaft between your thumb and a finger and try moving the input shaft side to side. It shouldn't take much force-just a few pounds,a kg of pressure or less. The side to side movement, I think you'll find, is normal. Even with this apparent flexibility, the shaft still needs to be located(usually within a few thousands of an inch,0.08 mm of the centerline) and well supported as with the pilot bearing. Otherwise, the bearing and gear problems mentioned before might occur. 

Every typical front engine, RWD vehicle I've seen has a trans. with this design feature . It's not a flaw(assuming it's not worn out), it's just a simple, convenient design that requires the pilot bearing to locate and support the outboard end of the shaft. DIYers run into this problem all the time when they try to use this type of trans. as a auxiliary gearbox on a lathe or other pieces of equipment. If they try to put a sprocket or pulley on the input shaft, a well located extra support bearing is required to prevent early failure of the trans.


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## piotrsko (Dec 9, 2007)

New question: did you grease either the adapter pilot hole or the pilot bearing end of the input shaft?


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