My journey to 40mpg with a 1ton diesel.

[crashnzuk]

The OPs truck has a Getrag which is where my advise was directed. The only things I know for certain about the NV5600 is that it was only used by Dodge for a few years and it is a very expensive transmission to repair. My advise is purely cautionary and is drawn from the experiences of other Cummins owners on other boards. If you hurt or destroy any manual trans in a cummins powered truck, it will very quickly eat up the value of any fuel savings you had realized.
Travis..

[slowmover]

The later six speeds (and 5-speed NV-4500) remain an option for nearly any CTD. I've nearly 200k on the original clutch on my 5600. And have driven 1T DRW oilfield hotshot (upwards of 30k gross, combined) where the trans does just fine (some install clutches with greater holding power) given the hardship. The near million-milers pulling heavy loads aren't and weren't breaking these transmissions.

"Breaking" a manual transmission is usually a matter of being a fool behind the wheel trying to hurry the shifts. Same mindset that adds a "tuner" where it is hardly justified (if ever) for the loads being moved.

Be sure to filter out those with commercial experience and those whose trucks are little more than toys.

A well-built automatic trans, OTH, will set you back $4k and more.

[crashnzuk]

I think we are pretty much on the same page. Yes lots of guys breaking stuff are doing so by abusing them. BUT, lots of people have had issues with their G360 in normal use from the time they were new. I don't hotrod or abuse my truck (91 W250 diesel, G360), but you won't find me lugging it and letting the trans and transfer case rattle like a box of rocks either. I don't think engine off coasting or extreme low rpm for the gear are good for the trans and wanted the OP to know that if it breaks it will be an expensive fix.
Travis..

[slowmover]

Yes, we are. It is for those who come along later (not knowing much at all abou these trucks, but are considering their use) that some tech points ought to be aired. Other manual transmissions than OEM are a possibiiity, and pluses/minuses weighed. As well as "what constitutes lugging". I'd imagine that I can -- with a Third Gen CTD -- come closer to that what with much more sophisticated engine controls. We none of us would recommend the last bit of FE if it compromises reliability/longevity, but some trucks WILL be more capable than others over a broader range.

[slowmover]

So what happened to this truck?

[mikeyjd]

Originally Posted by slowmover

So what happened to this truck?

I sold it after an icy winter and getting stuck without 4x4. I won't own another rwd truck as long as I live in Michigan.

I own a fleet of diesel box trucks now that I've done some light aero modding on, but haven't done much in the way of hypermiling the last few years being as busy as we are. My wife and I own/operate a major appliance retail/ repair company.

[gumby79]

yeah the two-wheel drives are a little special when it gets icy ,it's like a one-legged man trying to go ice skating. it makes lots of noise it gets attention but it just sits there.

Too slow movers point. The nv4500 5th gear nut backs off due to the harmonic resonance torque twisting the shaft. And yes 5th gear @25mph is lugged

[Tahoe_Hybrid]

Originally Posted by Big Dave

This project has a lot of merit. My truck is fairly similar.

Quick question: Stick or automatic? Just on the face of it a stick is good for a 2 MPG gain. An automatic pretty much forecloses engine-off operation unless you can repair automatics economically..

you can always get an electrical Aux transmission pump.. it was invented


good luck finding one GM owns the rights to it
https://patents.google.com/patent/US20100050626A1/en

[gumby79]

Originally Posted by Tahoe_Hybrid

you can always get an electrical Aux transmission pump.. it was invented


good luck finding one GM owns the rights to it
https://patents.google.com/patent/US20100050626A1/en

Wouldn't an electric power steering pump do the job?