Hello to all!

[Gary Lewis]

Yeah. My general goal for the future is to get thru college and get a decent Engineering job, so that I can make enough money to support my gasoline addiction, and enjoy my job in the process!

I was surprised to see the MPG from that speed of highway driving.

You can feel how un-aerodynamic it is when you get going fast. If you let off the gas, you start slowing down very quickly, even when going downhill.

It's even worse at high altitude; sometimes I can barely keep it at 60 with the headwinds out here.

I noticed a mileage difference depending on the speeds I drove. My best tank was out East on the slower roads, where I was doing 55-60 the whole time. With my gearing I'm doing around 2,000 revs at that speed.

Usually got high 18's around Kansas territory as the speed went up and the air density went down.

Not only does the wind resistance hurt the MPG, but the lack an overdrive hurts as well. Big Blue has that 460 spinning at 2500 RPM @ 65 MPH, which works out very nicely when towing but seriously unnecessary when cruising. And that is with 33" tires and 3.55 gears! So I have a ZF5 that'll go in to replace the T19 this winter, and that will drop the RPM to 1800, which is much more reasonable.

[can0fspam]

Not only does the wind resistance hurt the MPG, but the lack an overdrive hurts as well. Big Blue has that 460 spinning at 2500 RPM @ 65 MPH, which works out very nicely when towing but seriously unnecessary when cruising. And that is with 33" tires and 3.55 gears! So I have a ZF5 that'll go in to replace the T19 this winter, and that will drop the RPM to 1800, which is much more reasonable.

Oh, yeah. That's another good point!

I've thought about the idea of an overdrive conversion before, but I don't think I will do that anytime soon.

I would realistically have the option of a ZF5, Mazda five speed, or an earlier SROD/TOD/RUG/etc transmission.

My problem with the ZF and the Mazda is that they're very modern units. Both have integrated bellhousings (except some ZF's) and they also have internal hydraulic release bearings. I don't like the idea of running either of those on an old truck, where things in my opinion should be simple and serviceable. I've driven several Rangers with the Mazda five speed and they all feel sloppy and vague, in a non-feedback rubbery way, not in a classic "dump truck" way. I've never used a ZF before, but they seem to be a little tougher and better in general.

I could run a SROD or similar four speed overdrive, but the gear spread is not really any better than what I have now. I'd also lose a usable low gear, unlike the five speed units or my current granny gear. On top of that, the SROD and toploader overdrives aren't known for being very tough, and shifter parts are getting rare.

I like my NP435 for the most part. It could use a rebuild eventually due to normal wear, but I feel confident in trusting it to work whenever I call on it. With my axle gearing, it is the same or better than an overdrive transmission with 3.55 or 3.73 gears, except for the gear spread.

If I made a change, I would consider taller gears and a T19. I could use the synchronized, reasonable first gear to take off, and then I'd have enough high gears to be comfortable at 70 and above.

I have read about some super old-school Clark overdrive units and similar, which are basically ancient ZF transmissions (compound low, 2 underdrive, one direct, one overdrive). They are extremely heavy and sometimes not fully synchronized, but it would be interesting to try and run one of those!

Of course, for most sane people, a ZF5 is a perfectly fine option. I'm sure it would be a treat to have those close ratios and usable low and high gears.

I hope your swap goes well. Especially w/ the mass of a 460, those low revs will help.

[Gary Lewis]

Oh, yeah. That's another good point!

I've thought about the idea of an overdrive conversion before, but I don't think I will do that anytime soon.

I would realistically have the option of a ZF5, Mazda five speed, or an earlier SROD/TOD/RUG/etc transmission.

My problem with the ZF and the Mazda is that they're very modern units. Both have integrated bellhousings (except some ZF's) and they also have internal hydraulic release bearings. I don't like the idea of running either of those on an old truck, where things in my opinion should be simple and serviceable. I've driven several Rangers with the Mazda five speed and they all feel sloppy and vague, in a non-feedback rubbery way, not in a classic "dump truck" way. I've never used a ZF before, but they seem to be a little tougher and better in general.

I could run a SROD or similar four speed overdrive, but the gear spread is not really any better than what I have now. I'd also lose a usable low gear, unlike the five speed units or my current granny gear. On top of that, the SROD and toploader overdrives aren't known for being very tough, and shifter parts are getting rare.

I like my NP435 for the most part. It could use a rebuild eventually due to normal wear, but I feel confident in trusting it to work whenever I call on it. With my axle gearing, it is the same or better than an overdrive transmission with 3.55 or 3.73 gears, except for the gear spread.

If I made a change, I would consider taller gears and a T19. I could use the synchronized, reasonable first gear to take off, and then I'd have enough high gears to be comfortable at 70 and above.

I have read about some super old-school Clark overdrive units and similar, which are basically ancient ZF transmissions (compound low, 2 underdrive, one direct, one overdrive). They are extremely heavy and sometimes not fully synchronized, but it would be interesting to try and run one of those!

Of course, for most sane people, a ZF5 is a perfectly fine option. I'm sure it would be a treat to have those close ratios and usable low and high gears.

I hope your swap goes well. Especially w/ the mass of a 460, those low revs will help.

There are more modern overdrive units, like a Gear Vendors or Doug Nash. Jonathan has one of each of those and is trying to figure out which he wants to use with what transmission.

As for the ZF5, they are rugged and are a true truck transmission. The syncros are a weak point, so you don't want to hurry them in shifting, which is why that recently rebuilt ZF5 isn't going in Dad's truck and, therefore, is available for Big Blue. And the low 1st gear and tall 5th gear do work out very nicely. I ran that tranny in Dad's truck, prior to the rebuild, for several thousand miles and loved it.

Oh yes, thinking of it one way there are three versions of the ZF5: the small block bolt pattern one that does have an internal clutch slave cylinder; the big block bolt pattern unit with an external clutch slave; and a diesel unit with an external slave. But the gas versions have a wide ratio gear set and the diesel has a close ration set of gears, so that's another way to differentiate. And then there's the ZF5-42 vs the -47, which have 420 and 470 ft-lb ratings respectively.

As for the T-19, there are a few versions of those. Jonathan and I had a discussion about them in this thread recently. You might find it interesting given your engineering background.

[can0fspam]

There are more modern overdrive units, like a Gear Vendors or Doug Nash. Jonathan has one of each of those and is trying to figure out which he wants to use with what transmission.

As for the ZF5, they are rugged and are a true truck transmission. The syncros are a weak point, so you don't want to hurry them in shifting, which is why that recently rebuilt ZF5 isn't going in Dad's truck and, therefore, is available for Big Blue. And the low 1st gear and tall 5th gear do work out very nicely. I ran that tranny in Dad's truck, prior to the rebuild, for several thousand miles and loved it.

Oh yes, thinking of it one way there are three versions of the ZF5: the small block bolt pattern one that does have an internal clutch slave cylinder; the big block bolt pattern unit with an external clutch slave; and a diesel unit with an external slave. But the gas versions have a wide ratio gear set and the diesel has a close ration set of gears, so that's another way to differentiate. And then there's the ZF5-42 vs the -47, which have 420 and 470 ft-lb ratings respectively.

As for the T-19, there are a few versions of those. Jonathan and I had a discussion about them in this thread recently. You might find it interesting given your engineering background.

I forgot about those bolt-on overdrives. Those are a good option too!

Maybe when I have little more time and money and a little less mechanical things to get in order, I'll figure out my best solution for an overdrive!

Sounds like a big block or diesel ZF wouldn't be too bad, apart from the sheer size and price to obtain one. I'm sure it would help drivability.

IIRC those ZF's just run on ATF. My NP435 takes a GL-4 gear oil, so when I get around to changing the fluid I'm gonna have to find a place that stocks that.

With my NP435 and tall gears, I often have to use first gear if there's any amount of uphill to the road. My clutch is very old (maybe original) and has some chatter to it, so I can't slip it for very long.

Also I'm sure you know with your wide-ratio T19 that the gap from 3-4 in these trannies is astronomical. I can go around corners as low as 15 miles an hour and stay in third, and then shift to fourth at 30-35 and that's all I've got.