Manual versus automatic mpg on 2WD D350

[888]

When I converted my W350 from a 727 to a NV4500, it gained a good 4+ mpg (14 to 18-19). I still run direct (fourth) most of the time, runs 1700-1800 rpm @ highway speeds. Since the conversions, best mpg I've seen was 20.9 last summer. The 727 was really loose, and took quite a bit of throttle to do anything. My pile is lifted a little, and those 3.07's are spinning 35" tires...so I'm pretty happy with the mileage it's getting.

Apples to oranges, but something to chew on.

That's the kind of information I'm looking for, even though I have the 518 and you had the 727. The 518 seems to take a lot of throttle to do anything but my other car is a Jetta TDI which probably weighs half or less and has some aerodynamics to it so it's going to feel like a rocket in comparison. I just recall my D250 seeming to roll a lot freer and not struggling so much to keep speed.

Any reason you didn't use a Getrag rather than the NV4500? Did you end up getting a donor truck somewhere or did someone have a kit put together for the swap?

Thanks

[CumminsPower59]

I went with the NV because I had more NV parts than Getrag parts at the time. I sourced all the parts myself over a couple months so I could throw it together when I was changing out the body on my 91. Relying on some knucklehead somewhere to put a kit together for my truck isn't a good option. There aren't many parts needed for a auto to manual conversion, all of which you can source yourself. You don't even have to mess with a transfer case since you got a D model already. Even the wiring for the conversion is really easy

[CWT]

Is first gear pretty much useless also? I know in my buddies 94 unless you have a load behind it its useless. And if so and you only run direst in 4th gear most of the time its a 3speed basically. ha

[888]

I went with the NV because I had more NV parts than Getrag parts at the time. I sourced all the parts myself over a couple months so I could throw it together when I was changing out the body on my 91. Relying on some knucklehead somewhere to put a kit together for my truck isn't a good option. There aren't many parts needed for a auto to manual conversion, all of which you can source yourself. You don't even have to mess with a transfer case since you got a D model already. Even the wiring for the conversion is really easy

Thanks for the reply. Since the Getrag was the OEM option for the truck, I was thinking that was the way to go but I recall reading the Getrag had a 5th gear issue, is the NV a better option? I assume there is more that has to change to use the NV in place of the Getrag? Bellhousing and drive shaft for example?

[888]

Is first gear pretty much useless also? I know in my buddies 94 unless you have a load behind it its useless. And if so and you only run direst in 4th gear most of the time its a 3speed basically. ha

That was true on my 92, unless I had a load of firewood I started in second gear.

[DodgeFreak]

I went with the NV because I had more NV parts than Getrag parts at the time. I sourced all the parts myself over a couple months so I could throw it together when I was changing out the body on my 91. Relying on some knucklehead somewhere to put a kit together for my truck isn't a good option. There aren't many parts needed for a auto to manual conversion, all of which you can source yourself. You don't even have to mess with a transfer case since you got a D model already. Even the wiring for the conversion is really easy

Thanks for the reply. Since the Getrag was the OEM option for the truck, I was thinking that was the way to go but I recall reading the Getrag had a 5th gear issue, is the NV a better option? I assume there is more that has to change to use the NV in place of the Getrag? Bellhousing and drive shaft for example?

nv4500's had the 5th gear nut issue which is easily fixed a number of different ways. I have a getrag in my crew and its been a pretty stout trans for the abuse I put to it before we put it in the crewcab.

[CumminsPower59]

I usedsecond gen parts for the conversion: block plate, bell housing, starter. If that getrag had a good case, I probably would've used it. I can use first gear in my pile, it has 3.07's and with the 35's, first is mostly useable.

[cmann250]

Adjust your bands. I gained a solid 1mpg from that alone.

I'm a 3 pedal person so I honestly have no experience with this. Can you point me to a link to help with this? I have a factory manual set but it's from my 89, that had the 727 so I'm not sure it would apply and don't want to assume.

Thanks

viewtopic.php?f=22&t=7759

FYI, the front half of your 518 is essentially a 727. Chrysler did not change anything if they didn't have to. Stuff pertaining to over drive is 518-specific, but 1st, 2nd, and 3rd gear are the same mechanically and hydraulically as the 727.

[888]

Adjust your bands. I gained a solid 1mpg from that alone.

I'm a 3 pedal person so I honestly have no experience with this. Can you point me to a link to help with this? I have a factory manual set but it's from my 89, that had the 727 so I'm not sure it would apply and don't want to assume.

Thanks

viewtopic.php?f=22&t=7759

FYI, the front half of your 518 is essentially a 727. Chrysler did not change anything if they didn't have to. Stuff pertaining to over drive is 518-specific, but 1st, 2nd, and 3rd gear are the same mechanically and hydraulically as the 727.

Aha, thanks.

[dpuckett]

If you want a manual, are getting crappy MPGs, and it has a stock auto, just swap it out. I have done it in 2 pickups- mine nd my mom's. She gained 4+ mpg due to having a slopomatic convertor. I gained 2.5 or so. My auto was a little better, but still not great.

All the parts bolt right up. Use your current engine adaptor plate, tranny mount, etc. only hard part is deciding where to cut the shifter hole and driveshaft work. I think it needs shortened 5.5" or so, but check it yourself when you get to that point.

I would recommend going to Dodge and biting the bullet for the clutch hydro kit, though. I had a used hydro kit develop a leak in town one evening. Barely made it home.