The Stovebolt Site Forums The Shop Area Driveline Starter question for 55.1 GMC Hydra-Matic

My 55.1 GMC is a 248 with a hydra-matic. I am switching to a T5. What starter do I need? I believe that the original starter is specific to the hydra-matic, which means it should go to somebody who needs it.

Hy Joseph_Y, that depends if you want to maintain your six volt system or change to twelve volt at the time of transmission replacement. If you want to remain six volt you'll need a 139 tooth flywheel and a six volt starter for a 54 through 59 bellhousing. If you want to change to twelve volts, you'll need a 168 tooth flywheel and a twelve volt starter to fit the same bellhousing, hope that helps.

The previous owner converted it to 12V. The stamp on the starter says 6V though.

I have a donor chassis from a 55.1 GMC manual truck for the bell housing, clutch linkages, and a starter. It would be a 6V version though (I assume). Is there a way to rebuild it to 12V? Where do I find the 168 tooth flywheel?

When converting a 6 volt hydramatic transmission truck
to 12 volts you have to use the original 6 volt starter.
Because it's the only starter with the correct teeth that will match up to the 139 teeth hydramatic flywheel.
Picture of HM parts

In your case use your backup manual tranny bell housing, pressure plate, clutch, throw-out bearing, flywheel and starter.
Here is a 12 volt STARTER its for a Chevy, so I'm not for sure if it will bolt up.
I think some venders also make a 12 volt starter with a solenoid.
Otherwise you could use the manual tranny 6 volt starter. Just don't run it for a long time.
If you don't want the hydramatic flywheel send me a PM Pirvate Message.

Talk about a mark up. I had mine converted locally for $50.

What is the difference between the 6V hydra-matic starter and the 6V manual transmission starter? I do not have the manual transmission one in my hand yet, so I cannot look at them side by side. I am not picking up the donor manual transmission chassis until next month.

I am using the bell housing, crossmember, and flywheel from the manual transmission donor chassis. It is my understanding that I have to. I do not know which starter to use though.

Can I have a local shop convert the 6V starter to 12V and just keep the 6V flywheel from the manual transmission chassis? What is the negative of using the wrong tooth count?

I think Jorb has comparison photo of the two starters. The "snout" of the H-M-starter is a different length.

The "snout" of the H-M-starter is a different length.

The Hydra-Matic starter is the one on the top.

Makes sense that the top longer snout starter is the HM,
I thinks the reason for the HM starter being longer has something to do with that front housing.
Which the manual tranny doesn't use.

longer snout: The part you don't see when bolted up.

Nice Pic
tc

If your 6V starter is in good working condition there is no need to have it converted to 12V just for the sake of having a 12V starter. Mine needed to be rebuilt anyway and I asked if he could convert it and he said yes so I had him do it.

There is one problem he has a hydramatic truck toeboard.
There is no foot activated starter mechanism on the floor.
He needs a 6v or 12v manual tranny starter with a solenoid.

Can I put the solenoid from my hydra-matic starter on the manual starter? Or is that a silly question. I have no idea.

It is not a silly question, but you cannot. The drive-lever is different.

Chevs of the 40s used to sell a 6v solenoid starter (from a LCF truck). It will work, but there is a hefty core charge.

I do not know if the Powerglide 6v starter will work.

Do 55-59 trucks use a solenoid starter?

Can I use the snout from the manual starter on the hydra-matic starter? I believe the snout is the difference between the starters.

Hy Joseph_Y, I believe the armature shaft on the Hydramatic starter is too long to install a nose from a standard transmission starter on it.

Mechanical starters on '55-59 6 cylinder GMC trucks but '56-59 are for 12V flywheels.

I planned on using the flywheel from my 55.1 GMC manual transmission donor chassis. I have not heard about the 248 crankshaft being different for a hydra-matic though.

With the truck bell housing you can use the 6 volt car starter. It is a solenoid starter. You will most likely need a 12 volt solenoid, but you might not. I have a spare starter that has been used while the stomp starter is getting rebuilt. It is a 6 volt solenoid starter from some donor car. I put a column mounted horn button on to act as the starter button. You already have the button so that part is done for you. It has worked so far and I have yet to change it out. About a year of dump runs, errands and just fun drives so far.I would match the starter to the flywheel and go from there.

The 55.1 GMC manual transmission flywheel will have 6 mounting holes to the crankshaft. You need to see how many bolt holes is in your crankshaft.

He is using a 1954 GMC truck clutch housing.
Is the Chevrolet passenger car starter w/solenoid interchangeable with the GMC truck clutch housing?

I can see Chevrolet truck and Chevrolet car parts being interchangeable.
I do not know about GMC.

Hy Joseph_Y, all the linkage for the stomp starter is bolted to the engine not the floor, so you only need a hole in the floor for the button shaft to pass through. Or you could use the car solenoid starter of the correct voltage as Steve_H has suggested.

The '54 Chevy and GMC clutch housings are interchangeable. The starters are too.

ref: Hollander Manual, 32nd edition.

OK, here's the low down on the Chevrolet Starter w/solenoid info.

The 47-54 Chevrolet Truck Factory Assembly Manual Shows:
R.P.O. 327 Solenoid Starter Equipment Instruction
Section 0, Sheet 3.00
Looking at starter it says,
part #1107109 motor assembly

Section 12, Sheet 7.00
That sheet says same part #1107109 but RD right hand drive truck.

1954 Chevrolet Car Spec sheet PDF page 41 under starter motor it says same part #1107109

1954 Chevrolet truck Spec sheet PDF page 114 under starter motor it says same part #1107109

Master parts catalog Grp. # 2.041 Motor Assembly, Starter It does not show that part number for some reason. Just part #1107108

Note:
Chevy manual and H-M tranny flywheels both have 139 teeth and use 6 bolts to attach to crankshaft.
Chevy manual and H-M tranny starters both have 9 teeth on starter pinion.
Both the manual and H-M tranny starter drive end housings are the same length.
The difference is, the mounting ears on the H-M drive end housing are closer to the solenoid.
Which allows the starter drive end housing to insert farther into the bell housing, because the H-M flywheel is set back from the crankshaft.

The above info tells me, the manual transmission 1954 Chevrolet passenger car starter w/solenoid part #1107109
will work on a 1954 Chevrolet 3700 3900 series manual tranny truck. And probably any 3000 series truck.

Like cletis said it will come down to the flywheel fastening bolts 6 or 4.
If you have 6 it will work if 4 it will not.
You have to use the Chevy 139 teeth flywheel with the 9 teeth starter pinion.
You would think that someone could convert a GMC stomp starter to a solenoid starter.

OK folks, my mind has cleared a little. I stated above (now removed) that a '54 Hydra-Matic engine may have used a 4 bolt flywheel. What caused my confusion is a '53 Hydra-Matic used a 6 bolt flywheel 228 and all other 228s were 4 bolt.

All '54 248s had 6 bolt flywheels regardless of transmission used. The starter and flywheel from the '55 titled truck should work for you.

I picked up the manual transmission donor chassis this past Saturday. I had good weather for the entire trip except for when we loaded it on the trailer. Low 40s and drizzling. Overall, it was a pretty smooth 480 mile adventure.

The engine, bell housing, and transmission from the donor chassis is covered in an inch of grease dirt. The stuff is hard as concrete. I will try to clean it up this Saturday so I can remove the bell housing.

I now have an original 3-speed manual transmission that I do not need.