huckstep

First what I'm trying to gain: Fuel mileage, and reliability.

After all, that's why I chose a Cummins...

I just bought a 96 2500 4x4 w 155K miles, it already has a K&N air filter and some kind of custom split exhaust.

The transmission is original stock and still shifts fine but the Torque Converter seems to have a few problems (locks in 1st and R, won't lock at freeway speed etc.) I may be able to get the TC fixed with just with a new TCC solenoid, but I might just go ahead and get a good TC now since I know it'll happen pretty soon anyway.

3 Main Questions:
1.) I'm thinking about changing the final drive ratio from 4.1 to at least 3.55 or 3.23 or maybe even 3.08 like some of the 1st gens had. The main reason is to gain fuel efficiency, please tell me if think this is a bad idea. Also I wonder if I'll have any problem towing an 8,000 lb travel trailer with the taller gearing. I'm thinking if I do, I can always put in a #8 or #10 plate to bring up the power to compensate (gotta find some reason to justify power ).

2.) Will a good TC be enough in the tranny for now with the fairly mild mods I'm contemplating? I'm assuming the stock tranny will die at some point, but will it's death be significantly accelarated by not getting a built valve body? A good tight TC is important to me because it'll give both better mileage and reliability, but I'm not sure what a VB would gain me at this point.

3.) Is an EGT gauge important for me with at most a #10 plate? What about boost?

I'm pretty sure I will get a Tranny temp gauge.

I thought about asking about stall speed etc on the TC to meet my goals but I figured any of the big 3 would be able to answer that question when the time came.

Thanks! I've learned a ton just from reading the old posts already!!

infidel

At least a pyro is essential if you are anything but stock.
Lowering your rpms won't effect fuel economy much at all. Slowing down is more important due to increasing aerodynamic drag the faster you go.
Ask anyone who has lost 5th gear and had to drive extended miles without it. Revved up higher but still going slower most all find their best mpgs ever.
People that have an aftermarket overdrive unit also report no gain in mpgs.

huckstep

Wow, that is great feedback.

So there's no reason to consider something like a GearVendor?

I'd wondered why I hadn't seen any in peoples sigs.

displacedtexan

You would probally never recover the cost of the unit in fuel savings. It also adds more drivline drag to overcome...

torquefan

My 96 has 3.55 gears. I find this to be the ideal gear ratio for towing, and driving solo as well.