Manual transmission swap in m135

[MattG749]

New member. I have a couple of questions about putting a manual in place of the hydramatic. I can use a 235 bellhousing.
but does the 302 have a recess for a pilot bearing.
And can an np205 be used in place of the reduction unit will it hold up to continuous use..... im planning on using an sm465 Muncie 4 speed. And an advance adapters ranger 2 speed. And was thinking of using the np205 as a reduction unit..... if not I could use a spicer 5831E auxiliary 3 speed behind the 4 speed and use its 1.27:1 low gear as a reduction gear for 6wd. Only problem is finding one of those boxes.... which is why I want to know if the np205 will actually hold up to moving 12,300 lbs regularly..... and almost 17,000/20,000 lbs when loaded.....

 

[m1010plowboy]

Welcome to the forum from the deuce refrigerator we call Canada.

I'm just the landscaper so check with the mechanic but I think one of the mating challenges is the bellhousing design commits an engine to the bell. It could have been a manufacturing process to speed things up but here's what they say.



I have one apart and looked for better pictures but here's what we have for input info. Bolting any transmission to this motor could help save a few trucks. There is a recess for a pilot bearing.

 

[DUUANE]

Welcome to the excitement. The civvy manual bellhousings that fit the 302/270 gmc are set up for a sm420 trans. It has a smaller input bearing retainer register than the 465 in later chev's . Not the end of the world but bellhousing will need to be bored out to work. What i hate about the 420/465 is the wide spread between 2nd and 3rd. A smart feller might be able to source a clark 280V from a late 60's C40 with single speed rear and make an aluminum adapter/spacer that takes up the extra length if the input shaft and adapts the back of the bellhousing to the front face of the trans. That way you could have the best of all worlds..a 7:1 bull low..and 4 synrchonized close ratio road speed gears. There is a truck for sale up here that ive seen with my own eyes that has a brownie. Im pretty sure they would sell it separately. I have one also but would like to hang on to it as a spare for another truck currently operating.

 

[MattG749]

Welcome to the forum from the deuce refrigerator we call Canada.

I'm just the landscaper so check with the mechanic but I think one of the mating challenges is the bellhousing design commits an engine to the bell. It could have been a manufacturing process to speed things up but here's what they say.

View attachment 818411

I have one apart and looked for better pictures but here's what we have for input info. Bolting any transmission to this motor could help save a few trucks. There is a recess for a pilot bearing.

View attachment 818409View attachment 818410View attachment 818412View attachment 818413

The 2 halves of the original bell housing were machined and planed to seal agains one another for submersion is my guess. I’ve seen the military blocks with 235 bell housings attached. My only real concerns are what clutch can I use throw out bearing
Etc. I’m trying to find one of those old spicer 3 speed auxiliarys 5831E or B .... it will solve the issue of how many gears I need and the issue of losing reduction gear for the t case..... if not I’m gunna have to try and cram a 2 speed from advance adapters along with an sm465 and an np205 in the truck to get the forward gears i need. And still have a low range..... I’m planning on turning into an m216 like you cunnucks had using it to haul rip rap and asphalt chip seal.

I also am going to be making my own set of wires to use the military distributor with civilian plugs. That won’t require cutting up military plugs only requires a trip to tractor supply. When I have them made I’ll try to post pics and explain the yank space magic I’ve got cobbled in my head......

 

[MattG749]

Welcome to the excitement. The civvy manual bellhousings that fit the 302/270 gmc are set up for a sm420 trans. It has a smaller input bearing retainer register than the 465 in later chev's . Not the end of the world but bellhousing will need to be bored out to work. What i hate about the 420/465 is the wide spread between 2nd and 3rd. A smart feller might be able to source a clark 280V from a late 60's C40 with single speed rear and make an aluminum adapter/spacer that takes up the extra length if the input shaft and adapts the back of the bellhousing to the front face of the trans. That way you could have the best of all worlds..a 7:1 bull low..and 4 synrchonized close ratio road speed gears. There is a truck for sale up here that ive seen with my own eyes that has a brownie. Im pretty sure they would sell it separately. I have one also but would like to hang on to it as a spare for another truck currently operating.

That’s what I’m trying to get the spicer 5831 for it would mount behind the 4 speed giving me 12 forward speeds the spicer would have a lo di and OD gear letting me split each gear in the 4 speed.
mans I could use the 1.27:1 lo gear in the spicer box as a reduction gear for 6x6 use.... be nice if I could find one been stalking vander haags for a while

 

[jasonjc]

How does that work mounting a 2 or 3 aux after the transfer case?? And does the M135 front axle have a reverse rotation?

 

[eric67camino]

I assume that you are planning on putting the 205 t-case or auxiliary gearbox/brownie box between the new transmission and the original transfer case?

 

[MattG749]

How does that work mounting a 2 or 3 aux after the transfer case?? And does the M135 front axle have a reverse rotation?

After the transmission..... and yes the rotation is reversed. Which means the ring gear and everything from a rear axle will swap into a front axle.

 

[MattG749]

I assume that you are planning on putting the 205 t-case or auxiliary gearbox/brownie box between the new transmission and the original transfer case?

Yes looking for the spicer/brown lipe 5831 from the 60s. Would be perfect for this.

 

[eric67camino]

Home - Gearvendors

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At one point, I was looking at doing a similar build to what you are. I found the gear vendor's unit that looked promising, but never got much farther on the concept. They claim to be good for up to 2000 hp engines and for 25,000 pound rvs. Would need to verify that overall length with transmission, adapter, and overdrive unit would fit and still allow small drive shaft to transfer case.

Of course the next concern would be can the transfer case and axles take the increased rpms that the increased road speed would cause.

 

[MattG749]

Home - Gearvendors

RACING AND TOWING PERFORMANCEOVERDRIVE ECONOMY The Absolute Highest Horsepower Handling Overdrive you can buy! Gear-Splitting Performance and Overdrive Economy. For RV’s, Trucks, Muscle Cars, Hot Rods, and Racing. The Finest Quality Auxiliary Transmissions. The Ultimate in Horsepower Handling...

www.gearvendors.com

At one point, I was looking at doing a similar build to what you are. I found the gear vendor's unit that looked promising, but never got much farther on the concept. They claim to be good for up to 2000 hp engines and for 25,000 pound rvs. Would need to verify that overall length with transmission, adapter, and overdrive unit would fit and still allow small drive shaft to transfer case.

Of course the next concern would be can the transfer case and axles take the increased rpms that the increased road speed would cause.

I’ve never really heard very good things about the gear venders unit. .... not to mention the $3000 price tag... and they are very long ..... I was only planning on getting the truck up to about 65mph at 1800-2000 rpm these engines don’t rev very high and don’t like to be wound out. So the lower I can keep the rom the better....

 

[DUUANE]

I think overall length will be the issue. Off the top of my head the Hydramatic is 33" OAL as i remember it. and the jack shaft is very short. A full synchro 4 spd in front of the brownie might fit. One of the nicest shifting transmissions ive ever had my hand on is a T19 out of a 84 ford with a 6.9. Close ratio so no stump puller 1st gear, but would work great with the brownie.
Eaton fuller RTO6610 is 28.3" and RT610 is 31.2 " long so if you dont care about pro shift these would fit and be the hot ticket with a built in low range. A custom clutch disk and an adapter and youd be stylin. RT's can be had reasonably but the RTO is pricey.
I'l put a tape across the brownie and T19 i have here tomorrow and report back.