Old granny gear swap..... maybe?

Jesus Freak · Mar 8, 2023

Okay, so in the absence of @PossumTruck , I was getting oil at a local shop and they work on a bunch of old Fords and I asked the owner about a PTO knowing he didn't have anything. Well a kid there says he has a 70s granny gear tranny with a PTO. So my question is this: will the dinosaur 4 speed granny tranny of days gone by bolt to a T19 bellhousing? I'd probably invent a different way to power my hydraulics before I went this route, but if the kid really got right on the price then it could be an option.

FrozenMerc · Mar 8, 2023

Your T19 should have a PTO access / mounting cover, mine has 2, one on each side.

That said, yes the "granny" gear transmissions have a PTO access point as well. They were generally used behind gassers and would either be New Process 435's or a T18 / T19 with the wide ratio. Close ratio T19's were put behind our beloved IDI's (and some 460's)

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u2slow · Mar 8, 2023

PTO fitment (gear mesh) is usually very specific to invidual transmissions and tcases. I think that's why the OP want us to swap the whole thing and not just the PTO.

Jesus Freak · Mar 8, 2023

u2slow said:
PTO fitment (gear mesh) is usually very specific to invidual transmissions and tcases. I think that's why the OP want us to swap the whole thing and not just the PTO.

Yeah, that's the deal. I have a ZF5 pto, even though it bolts on the T19 it's a different gear inside. So if I could just get a whole tranny with a PTO it would work or if I could just get a T19 PTO.

Black dawg · Mar 8, 2023

435 t18 and t19 all bolt to the same bell, same input splines and pilot.

Jesus Freak · Mar 12, 2023

I really might have a shot at a NP435, if the kid gets right on the price. Does anyone have a thought on one of these behind our diesels? If he gets silly with the price, I'm even considering just rebuilding the ZF5 and dealing with it and maybe I can come up with a 5something:1 differential one day. The T19 PTO has become a unicorn.

I'm also thinking about putting my hydraulic pump where my AC compressor is. I won't ever do the AC on my trucks and it's an available v belt to turn it. I'd get an elec clutch for it.

Jesus Freak · Mar 12, 2023

I'll tell you my concern about the NP435, I think it's a legitimate concern. It's really a 3 speed transmission. First isn't synchronized, it's just low gear. So will I be wound up crazy tight trying to shift into road gear? I guess a C6 will make our trucks move, but does it really?

hacked89 · Mar 13, 2023

what’s your goal again? If you want a low first gear why not just mod a 460 zf5 or swap the guts. Those are upper 5.x ratio 1st and an np435 is low 6.x it’s not far off. Then use your zf pto.

Jesus Freak · Mar 13, 2023

hacked89 said:
what’s your goal again? If you want a low first gear why not just mod a 460 zf5 or swap the guts. Those are upper 5.x ratio 1st and an np435 is low 6.x it’s not far off. Then use your zf pto.

I guess the goal is a lower 1st and R. And to make my truck useful again. And of course, on a budget.

Booyah45828 · Mar 13, 2023

Sounds like a 460 zf is what you want then. Diesel zf's are horrible 1st and reverse. I wouldn't want one if I were pulling trailers frequently or in tow truck service.

hacked89 · Mar 13, 2023

Jesus Freak said:
I guess the goal is a lower 1st and R. And to make my truck useful again. And of course, on a budget.

Yep, just use a 460 zf5 and be done with it

Jesus Freak · Mar 13, 2023

hacked89 said:
Yep, just use a 460 zf5 and be done with it

Well, that raises the next question. Do you got some 460 zf5 guts laying around?

hacked89 · Mar 13, 2023

Jesus Freak said:
Well, that raises the next question. Do you got some 460 zf5 guts laying around?

The 460 zf5s are cheaper than the diesel ones and maybe someone would even trade you. Haven’t done a guts swap but they can be drilled and bolted on.

Post in thread 'Compatability of ZF Gas 460 trans with IDI'
https://www.oilburners.net/threads/compatability-of-zf-gas-460-trans-with-idi.34788/post-389886

u2slow · Mar 15, 2023

Apparently you can reload the ZF5's gas ratio guts into the diesel case. In my locale, the gas ones are getting scarce and pricey. I reckon most such trucks saw the squisher 10+ years ago, whereas the diesels tended to last longer.

The low first gear isn't usually a problem with a diesel. I used to run the Chevy 6.2L diesel with the 4spd (6.55:1 first gear) and used 1st regularly because I had 3.21 axle ratio with 33" tires. Of course you can't really downshift into that non-syncro gear.

Similar scene with many Cummins trucks. The trans is 5.xx 1stgear and the axle is commonly 3.54. starting in 2nd is normal.

Jesus Freak · Mar 15, 2023

u2slow said:
Apparently you can reload the ZF5's gas ratio guts into the diesel case. In my locale, the gas ones are getting scarce and pricey. I reckon most such trucks saw the squisher 10+ years ago, whereas the diesels tended to last longer.

The low first gear isn't usually a problem with a diesel. I used to run the Chevy 6.2L diesel with the 4spd (6.55:1 first gear) and used 1st regularly because I had 3.21 axle ratio with 33" tires. Of course you can't really downshift into that non-syncro gear.

Similar scene with many Cummins trucks. The trans is 5.xx 1stgear and the axle is commonly 3.54. starting in 2nd is normal.

I was reading somewhere about the bearings in the front of the case can be damaged by how diesels torque or something. It's really appearing like my best option is to mount the hydraulic pump in such a way as to use the v belt to drive it. As far as the NP435 goes, it's more and more appearing that the PTO is transmission AND application specific. So it's coming around to finding a unicorn 460 transmission, a unicorn chealsea Dana pto for a T19 that is set for THIS hydraulic pump, or invent a mount to put the pump on my engine. And I don't have the $$$ for unicorns.

Old granny gear swap..... maybe?

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