Clean slate: which manual trans to get.

[Thaddeusrex]

I’m building a ‘72 for 99% spirited street driving. I’ll take it up forest service roads a couple times a year, and to snow for skiing, otherwise it’ll live in Bay Area on streets, and I’m a very aggressive driver. It’ll have a 347 SBF with 400-450 HP and torque. Atlas II, 4.11s, and 33” tires. 2.5” suspension, and 1” body lift, with Duff Dual Sport 4-link rear and Duff front suspension too.

I have a ZF5 S-42, but it’s going to probably need $1K of work to refurbish it. Was gonna use the ZF, but then got to thinking, maybe there’s a newer/better manual trans I’d like better for spirited street driving, and that my petite wife would like better, and that fits better in the Bronco. I don’t know transmission models, no experience picking one. The ZF is huge, requires chopping up the tunnel (already done tho), and the shifter hat comes up way up under the dash, requiring some funky shifter linkage to make it reachable.

I’d also like at least a 5 speed, with a good low first, and a 75mph cruiser 5th for the freeways around here.

i hope I’ve provided enough details, but if you guys were starting with a clean slate on this rig, what would you pick?

 

[1969miller]

AX15 hands down..

https://www.wildhorses4x4.com/early...manual-transmission-kit-with-new-transmission

 

[Broncobowsher]

M5R2 another option. I've wondered if you could run a set of SuperCoupe gears in the truck case.
Tremec 4050 can be had new, but it will be less sporty and more like your ZF.

 

[JB Fab]

I have Broncos with both the ZF & the AX
I personally like the ZF if it's got a short throw kit and a lighter shifter handle.
AX-15 is sportier, but OP stated " I’m a very aggressive driver. It’ll have a 347 SBF with 400-450 HP and torque", so maybe not the best choice for an AX15.
Wasn't there someone doing a custom upgraded NV3550 a few years ago?

 

[Timmy390]

I studied this long and hard before I made my switch. I ended up with an M5ODR2. I was going to go ZF but because I'm 99% street and only offroad is fire roads on the deer lease and some mud here and there I didn't feel I needed the ZF. No rocks......

The ZF is stronger but the R2 shifts much nicer. I can jam through gears fast and smooth. The later R2 also has a MUCH better shifter location.

As to torque rating.....Remember the Bronco Is not as heavy as the F150 the R2 came in nor are you going to be in the max HP or torque band driving around the streets. I drive mine hard with a warmed up 351W, 4.11's and 33 M/T's. I even pull a 12 foot utility trailer around all summer with a lawn mower on it. No issues......

JMO.....

Tim

 

[Timmy390]

Wasn't there someone doing a custom upgraded NV3550 a few years ago?

You mean these guys? http://tcase.rsgear.com/products/transmissions/terminator™.aspx

I wanted to go with the above but availability was an issue......So I started looing ZF or M5ODR2

Tim

 

[.94 OR]

My understanding is, the ZF only comes behind the 5.8 and you would want a 4WD version.
There is a ZF that bolts up to the 460 (had one) and the Diesel. These will not fit the bolt pattern of the Windsor block.

 

[Broncobowsher]

My understanding is, the ZF only comes behind the 5.8 and you would want a 4WD version.
There is a ZF that bolts up to the 460 (had one) and the Diesel. These will not fit the bolt pattern of the Windsor block.

Correct. And I believe there is also a mod motor bellhousing pattern as well, also won't work.

 

[nvrstuk]

Street driving means a lot of shifting and enjoying rowing thru the gears, staying in the torque & power range of the engine to be able to put that power on the road and not have to feel like you're driving a truck. A ZF is a truck trans and you can't get around that. Do you want a ZF in a Mustang for cruising around town? Course not because you'll never need 1st gear because it's so low AND because you now have a 3spd with an OD gear you have HUGE gear splits making the trans a dud for fun around town.

Go with the AX or M5 trans as their gear splits are much closer, those tranny's shift easier making them much more fun to drive. I've driven them both also.

I drove a ZF for a dozen years in my '68. I drove a 3 spd with an OD in that same Bronco for years... the 3 spd w/OD was a major disappointment. The ZF was a great trans for rocks, trails and also very driveable on the street but I also stuffed a 4 spd toploader in this same Bronco back in the late '80's early '90's and let me tell ya- there is NO comparison between rowing thru the gears in a ZF around town and powering thru the gears with a 4 spd toploader (Mustang/Torino transmission) where gear splits are so close and having a kick-arse time doing it. Makes the Bronco the hot rod it isn't, but definitely as close as you can get with it. Next is suspension, tires, etc, etc...

Have fun.