Manual transmission swap ideas 6, 8, or 10 speed

[454cid]

A detroit would suit me fine. Just way more power than i need.

...and weight. They're huge.

 

[R422b]

...and weight. They're huge.

Very true.

 

[JCribb]

Look at the medium duty trucks like the 5500-6500 series, those had a 6 speed option, but I don’t know if that was available with the gas engines. The one that I drove that was a 6 speed had a small cat motor.

 

[1989GMCSIERRA]

I have a gearvendors overdrive on my F350 ZF6 diesel. That’s about the only way you’re gonna get such shift pattern out of a regular manual transmission.

Unless you’re gonna swap the drivetrain out of a 18 wheeler......

 

[Trigger_guard]

Ok so. Advance adapters sells an overdrive that bolts between the standard Chevy bellhousing and any of the Muncie 4 speeds. This will act as a splitter, giving you half gears. 1/1.5/2/2.5 etc... But these are hella expensive.

Eaton used to make a medium duty 13 speed. But they're awfully rare. This would have an sae bellhousing so you'd also need an adapter. Unless you actually want to use a 53 series Detroit.

Another option would be to find an Eaton or Rockwell 2speed rear end out of a 2.5ton truck. Like an FL60 or an old F600. Loads of suspension and brake work tho

Since you're 2wd you could also do a divorced setup. I.e. put a 4spd somewhere between your trans and diff. This would probably be the cheapest option. But you'd have to find a yoke that will fit onto the input shaft.

Or just go the gear vendors route

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[Trigger_guard]

Sorry for the long posts. But I just want to add.

The transmission you're asking for is a full size Eaton. And there's just no feasible way to do it. IF you could adapt it to a small block. It's literally the size of a small block. And weighs 800 lbs. And 90% of the time you'll drive it just like a 5 speed anyway.

Something to consider tho OP. Used tractors aren't as expensive as you would think. I don't know where you're at. But I could probably sell you one for less than $5k, ready to shift your hearts content

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[b454rat]

I had a 3500HD that I wanted to build. Didn’t wanna use an NV4500, and a NV5600 is ridiculously expensive. Eaton makes a medium duty tranny that is almost a twin as far as gears n ratio goes, but has a 800lb/ft torque rating for a 30k truck. I can’t remember what it was called, but wanna say started with an 8, then 6, how they classify the trannies, torque input, how many gears, etc. Problem ur gonna have is trying to fit it under there. An Allison doesn’t fit under these very well without a sledge hammer....I’ll try in find the chart for said tranny.

 

[b454rat]

I think it’s called FSO-8406. Over 800lb/ft torque input, for a medium duty truck. Another problem ur gonna have is a bell housing. You can get adapters to bolt pretty much any tranny to any motor. But it’s gonna require clearing the firewall, like hacking it out, to get it to fit. Local junkyard has medium n heavy trucks, so could have gotten one relatively cheap...