The Other Doubler

[fabjunkie]

There was a thread on pirate going for a while that has died off about doubling up sm465's. Anyone on here do it? Seemed there were a few guys that had doubled up manuals or auto/manual. One guy over there had custom made the output/input shaft for the 465's but the tech wasn't very abundent and then died. Curious if anyone is producing these or if would still have to be a custom job.

 

[78Buford]

The main problem with doing that is the second transmission is very vulnerable to breaking.

Say you have a healthy engine that puts out 400 pounds of torque. The first 465 trans will receive the 400 ft lbs, and laugh at it. For the sake of nice round numbers, multiply it by 7.0

465 #2 will receive 2,800 pounds of torque. It won't laugh at 2,800 lbs of torque. Snappy snappy goes the input shaft on trans #2.

Even with a weak engine, 200 foot pounds of torque, you are putting way more power to the second transmission than it was ever designed for...

Roy

 

[sled_dog]

There was a thread on pirate going for a while that has died off about doubling up sm465's. Anyone on here do it? Seemed there were a few guys that had doubled up manuals or auto/manual. One guy over there had custom made the output/input shaft for the 465's but the tech wasn't very abundent and then died. Curious if anyone is producing these or if would still have to be a custom job.

There is a topic somewhere in "Center of Gravity" about it. MJ was working on it and someone else, don't think either ever finished.

 

[diesel4me]

farm trucks!..

I've seen many home built tractors and farm trucks with "brownie" trannies installed behind the first tranny..most of them used a huge tranny from a tractor trailer truck ,in order to withstand the high torque generated by the first tranny..never saw any of them break,but we all know how HEAVY a big 13 speed tranny with a "road ranger" shift is!...

I've seen a few SM465's coupled together at truck pull competitions,but many of them broke after a few runs..often cobbed together with blobs of weld and home brew shaft couplers..the trucks pulled very well until they broke though!..

I'd like to have a manual tranny behind an automatic like a TH400--then you could pick what "range" you want when wheeling,and let the automatic do the shifting!--then put the manual back into 4th or whatever gear is 1:1,and drive home!..--then you'd have a "tripler" or "quadrupler"!..

 

[sope]

A local gut here is running this set up in an S series blazer. I don't know him but the truck is on the road and trail with it. It has a 305, 700R4, SM465 14 bolt and D44

 

[Hossbaby50]

A guy on here with a big Burb had the double 465 setup. He snapped the input shaft off like others are mentioning. If you only used the first tranny in 2nd, 3rd, & 4th gear you might be ok but if you send 7x the power of the motor to the 2nd tranny you will most likely have some breakage issues.

Harley

 

[MattK]

hope you got some wheelbase to run a setup like that.

 

[fabjunkie]

Yeah, I went back over the thread on pirate and it said that it adds about 12" to the length. I guess I'll just save and get a 203 and an adapter. Might be something to play with in a lb though.