1952 M135 Converted to standard shift.....

[Brad]

My Dad's M135 had to be converted to standard tranny cause we were having so much trouble with the original.
He had a second truck that a local municipality once owned that had been converted, so we just switched everything over, and it's working prettyt well.
But we need a flywheel cover, and we have no idea what components these old timers used to do these switch overs.
So we dont know what to look for?
I'm hoping someone out there is familiar with these conversions and might know what the bell housing was that was used for the conversions?
Then I'll go looking for one.
I would think its old HMC or Chevy stuff, but really dont know?
Any help is sure appreciated.
Thanks in advance,
Brad

 

[JasonS]

Assuming that you still have the 302...

The 302 was available with two different bellhousing sizes over its production run: one with an 11 or 11.5" clutch and one with a ~14 inch clutch. If you have the small one, you can use a flywheel cover off of anything chevy or gmc pickup to 2.5 ton. I had the smaller bellhousing with a clark 5-speed on my M135. If it is the larger, you will need to look for a late fifties, larger truck.

 

[91W350]

We used the Chevrolet Muncie 465 in our conversion and a brake pedal, master cylinder and rod out of an Impala. The bell housing had the standard 11" clutch and the dust cover was the same one used on most manual GMC or Chevrolet light duty trucks through 1972.

 

[rainbow]

I have converted several gmc's to standard transmissions both four and five speeds. To make a good truck out of them you should convert the transfer case to two speed . I have one truck with this combination with a three hundred horse power chevy v8. Truck groses 36000 pounds. Have never broken anything yet. MY phone number is 785 486 3350 if I can be of any help

 

[SEADUCEME]

Hello rainbow...im about to convert my 1952 m135 to a 5sp and would sure like to talk to you... I'm SEADUCEME...steve 2038682287 anytime 24/7 thanks

 

[Section8]

Rainbow man!
I would love to know how you over came the linkage to the transfer case to select forward and reverse gearing?
I have read in the forums here that these particular transfer cases require a shift either forward or back to be able to run in said directions.

 

[rosco]

Rainbow man!
I would love to know how you over came the linkage to the transfer case to select forward and reverse gearing?
I have read in the forums here that these particular transfer cases require a shift either forward or back to be able to run in said directions.

Converting the Automatic Transmission to a 5 speed is far easier said then done! At best you are left with product with several glitches. Even so, I drove it thousands of mile in a rough country - from as far South as Grand Prairie, Alberta to the North Slope.

There are several shift levers under the seat/or places for them. I used one of the spots & an extra original lever for the shifting of the T-case for the front axle drive. There was no one around here for me to talk to, 40 years ago, when I did mine. I had to shift both when I went from forward to reverse--shift shift the T-case to reverse, Etc, otherwise the sprage clutch would lock up and the front axle would drag. That is to say, it would skid. It was a far superior sprage then the M35 uses.

I continued to use the original T-case by converting it to a two speed. I did that by shrink fitting a solid piece in place of the idler gear bearing, that is used to drive the winch, But! No neutral in the T-case, so the winch had to be driven with a PTO from the 5-speed tranny. This whole process is simplified, if one doesn't insist on a front drive or a winch, or two speed T-case.

 

[DUUANE]

Hi Rosco..i'm curious about the 2 spd tcase conversion process..what is the process and what ratios do you end up with? Is it reduction in both ranges? I was considering a solenoid controlled air actuator for shifting the sprag..parallel in a relay with the reverse light switch. Spring to hold the spool valve in drive..solenoid to pull it into reverse. If i could have a 2 spd tcase i would very much like that as i have pto openings on the allison. Any direction you could give would be greatly appreciated.

 

[rosco]

Its essentially a Hi & Lo range. You have to look in the T-case. The big gear in there is fixed to a shaft. But between the shaft & outside diameter of the gear, there is a large bearing that allows the outside to rotate freely -- or drive the PTO when selected. I turned a spacer that took the place of the bearing, so the shaft could transmit power as for a low range. So you have a highway gearing & low range, which was about two x one.

The air shift is a good idea - there are things off the shelf that you can use. I didn't think of that.

 

[DUUANE]

Thats great thank you..maybe ill try and find a spare tcase to do some exploritory surgery on..

 

[Ashley P]

Rosco, those mods are right up my alley. I've got a 211 with a small block chevy and 4 speed from an old grain truck. I lack low enough gearing to move out of soft ground when loaded. I'd benefit from a 2 speed transfer. Thanks for the info.

Duuane, if you do an exploritory, please document it here for my benefit!

 

[DUUANE]

I made it back to the shop..ill look into getting a spare tcase to mess with this week..if i can ill take as many pictures as i can. From rosco's message it sounds like its the pto drive gear and shaft that the action all happens on. I'm a little worried about sending power through a shrunk fit piece..ill have to look deeper and see if there is another way maybe make a new 1 piece shaft..