what the heck is this transmission?

[mac14562]

Member since July of 2017, trolled the forum for a couple of years, then rescued my 74 in pieces from a shop in Colorado. Waiting for retirement in a couple of years to get serious about the restoration but trying to gather info and parts now. The tranny is just sitting on the crossmember, so I took a few pictures. I was told by the seller that he thought it was a 3spd but wasn't sure. No tag, but there are casting numbers on the passenger side. Regardless of what it is, I'll probably be switching it out to a 5spd. Any info would be appreciated.

 

[RM70]

Looks like a NP435

 

[EPB72]

Looks like a NP435

Correct..with an advance adaptor adaptor ..

 

[mac14562]

so, the next stupid question.....since it's a 4spd, would this be an acceptable tranny to mate with a 302 with EFI? Rear end gearing is 3.50, probably going to run 33s with 17-18 inch wheels. Mostly city driving with some highway and some mild trail exploring. Pros and cons?

 

[thegreatjustino]

The NP435 is basically a three speed road transmission with a granny gear used offroad or when hauling heavy loads or starting while towing. You'll never put it in first gear just putzing around town.

It's also a big heavy duty truck transmission that shifts as such. With the long shifter bent correctly to clear the dash, you'll feel like you're rowing a boat with the long throws of the shifter. With that said, I've had one in my '69 for nearly 20 years and see no reason to change it out.

Being a four speed, fourth gear is 1:1 just like the stock three speed. No overdrive. The NP435 with 3.50 gears and 33" tires is just about pushing it for drivability. Most would suggest 4.11 gears for that combo, but that also depends on how much torque your engine puts out. An engine with more torque can make up for some lack of gearing.

 

[DirtDonk]

You won't necessarily be singing it's praises around town, but on that occasion that you do go exploring off road, it's a real game changer! With that low first/low gear you can really roll along comfortably over obstacles without as much banging around. Especially with those 3.50 gears and 33" tires.
That is a lousy combination for a trail rig, but that type of transmission really gets the job done.

Which is why they are so popular in trucks, and used to be the go-to transmission swap into Broncos back when we bought them mainly for off-road adventuring.

Paul

 

[sprdv1]

Correct..with an advance adaptor adaptor ..

low and slow 1st.... crawl time

 

[sprdv1]

so, the next stupid question.....since it's a 4spd, would this be an acceptable tranny to mate with a 302 with EFI? Rear end gearing is 3.50, probably going to run 33s with 17-18 inch wheels. Mostly city driving with some highway and some mild trail exploring. Pros and cons?

What Mr Justino said.... great for off road w/that low 1st gear

The NP435 is basically a three speed road transmission with a granny gear used offroad or when hauling heavy loads or starting while towing. You'll never put it in first gear just putzing around town.

It's also a big heavy duty truck transmission that shifts as such. With the long shifter bent correctly to clear the dash, you'll feel like you're rowing a boat with the long throws of the shifter. With that said, I've had one in my '69 for nearly 20 years and see no reason to change it out.

Being a four speed, fourth gear is 1:1 just like the stock three speed. No overdrive. The NP435 with 3.50 gears and 33" tires is just about pushing it for drivability. Most would suggest 4.11 gears for that combo, but that also depends on how much torque your engine puts out. An engine with more torque can make up for some lack of gearing.

 

[mac14562]

Great information. I was already considering changing the rear to 4.11 or 4.26. Also was probably going to go with a 3.5 in lift and maybe keep the 1.5 body lift that's on it, depending on the shape of the rubber. If I went with 35s what would be my expectations? I'm not sure what I'm going to do to the motor yet to help with power and torque. It only had a couple thousand mile on it before it overheated and seized up. It could be trash but I'm holding out hope that it may be saved. From what I've studied, the NP435 is bulletproof and can easily be rebuilt with a minimal amount of mechanical ability. From an economical point of view, I could restore it with the NP435 and drive it for a bit and change it later if I didn't care for it. The hardest part would be reconfiguring the drive tunnel to accept the shifter, eh?;D

 

[thegreatjustino]

If I went with 35s what would be my expectations?

My setup when it was last drivable was the NP435, 3.5" suspension lift, 3" body lift, 35" tires, 4.11 gears. Stock 302 converted to 4bbl carb and dual exhaust with headers. It was acceptable to me. Flooring it in fourth gear to speed up on the highway would trip the secondaries in the carb and move the Bronco well.

In the years since the above, I've installed a nice torquey 351, but have yet to drive it with this combo.

 

[okie4570]

I have the same setup with 4.11, no way I'd run 3.50 gears.

 

[sprdv1]

Great information. I was already considering changing the rear to 4.11 or 4.26. Also was probably going to go with a 3.5 in lift and maybe keep the 1.5 body lift that's on it, depending on the shape of the rubber. If I went with 35s what would be my expectations? I'm not sure what I'm going to do to the motor yet to help with power and torque. It only had a couple thousand mile on it before it overheated and seized up. It could be trash but I'm holding out hope that it may be saved. From what I've studied, the NP435 is bulletproof and can easily be rebuilt with a minimal amount of mechanical ability. From an economical point of view, I could restore it with the NP435 and drive it for a bit and change it later if I didn't care for it. The hardest part would be reconfiguring the drive tunnel to accept the shifter, eh?;D

buddy here in MO has ran the NP435 and 6 banger forever Hard Rock Crawlin too..

 

[jckkys]

I drove a 10.000 lb. truck and 120 hp 6 cylinder engine for 100s of thousands miles and never found a use for the "granny" gear. The 3 useful gears are very slow shifting. The NP 435 is very heavy duty, but that's all I can recommend it for. I'm lucky to live where there are real off road trails ie. they go somewhere. Rock crawling trails don't. So I can't care about that.

 

[mac14562]

jckkys, you brought up an excellent point. Trail riding and rock crawling can be two different mindsets. My job as a pipeline surveyor/inspector requires a lot of trail riding to get to the right-of-way of the pipeline. In fact, that's what I love about my job, that and I get to travel all over the U.S. But I know my limitations and extreme rock crawling doesn't interest me at all. i don't mind dirt and mud, I just don't want to tear anything up. I think I'll be fine with the NP435 and sink the savings somewhere else in the Bronco.

 

[toddz69]

jckkys, you brought up an excellent point. Trail riding and rock crawling can be two different mindsets. My job as a pipeline surveyor/inspector requires a lot of trail riding to get to the right-of-way of the pipeline. In fact, that's what I love about my job, that and I get to travel all over the U.S. But I know my limitations and extreme rock crawling doesn't interest me at all. i don't mind dirt and mud, I just don't want to tear anything up. I think I'll be fine with the NP435 and sink the savings somewhere else in the Bronco.

I think you'll be fine too. I ran my truck for 3-4 years with 3.50 gears and 33x9.50 BFGs and the 435 and it was a great trail combination (I do trail riding, not rock crawling). I used it behind both my tired old 302 and my 5.0, which was pretty fresh and peppy at that time. Loved the first gear for slow climbs and good compression braking.

Todd Z.

 

[marshall godron]

You should definitely look into the gear banger shifter from wild horses. Way nice and it takes care of the long throw while shifting

 

[marshall godron]

Dam. Cant I cant figure out how to rotate the pics %).

 

[mac14562]

yeah, I had the same problem with my pictures. I wasn't too concerned about the long shifter but I'm definitely looking into that setup. That actually looks pretty cool