Axle ratio/ e4od shift points?

[pybyr]

Like everyone else, I'm in $$ pain at the rising cost of fuel, and concerned that it may keep going up.

My truck has 4.10 axles- and since I will be opening the rear diff. up this summer to install a Detroit Truetrac, the thought of changing axle ratios comes to mind (the main deterrent being that I'd also have the additional expense and work of changing the ring and pinion in the D60 up front)

But-- I live in a very hilly area, and with no turbo, the truck can already become "winded" on long and/ or steep hills [hopefully this will improve when the Uhaul inj. pump and injectors go in when it warms up a bit outside].

So one of my questions is what happens to the transmission's shift points if I go from 4.10 to say 3.55. If they stay by governed by current MPH shift points, it'd be lugging too often.

Does one somehow do something to let the electronic transmission controller know about a different axle ratio?

An auxiliary overdrive would be really appealing, but a GearVendors is not in my budget and even if it were, would take too long to earn its keep in fuel savings when I drive only approx. 15,000 miles a year. Unless someone can point me to a good used overdrive at a very fair price....

Thanks!

 

[ManicMike]

If it's running out stream on hills NOW, with 3.55's you'll be better off pushing the truck up the hill. You also have a HEAVY truck; it's a 1 ton frame, duel rear wheels AND it has a toolbox body. EASILY over 7500lbs.

Honestly, your best option is make sure everything fuel-related (tank(s), lines, lift pump, injectors, and the inj pump) are all in great working condition. After that search for a turbo setup. It'll help power AND help MPG.

The E4OD doesn't care what ratio the gear's are, as long as the speedo gear is correct for the gear's used.

 

[Brianedwardss]

With that much weight and an overdrive, I'd stay with the 4.10's. Going to 3.55's will be a bit of work/$$, and on the hills it's gonna be struggling. As said, freshen up your fuel system, and if possible get it timed properly and you'll think you're driving a different truck!