TH350 and Gears

[Benelli]

I have a VERY Hard time pulling the water-tank up the hills, I have to put my K10 in 4-lo-loc, and I don't like too, because going down the hill it's a little un-nerving to try to swap out the t-case from low to high while having 4000 gallons of water pushing me down it.

I have 3.40 gears, would some 3.73's, with a posi-traction rear-end add anything?

What would you suggest? Using my Dad's diesel might be the best idea...especially when stopping comes to mind.

[Pyrotechnic]

What tire size are you running ?

3.42 with a 28" is a great combo, but since your truck is 4x4 I imagine you are running 33's or 35's ?

EDIT: Just dawned on me, but figuring 8.35 lbs for each gallon of water, times 4000 gallons, equals roughly 33,400 lb. That may explain why you are having trouble pulling it.

[glock35ipsc]

I would hope he meant 400 gallons! This is what I used to lug around 3000 gallons with, would never THINK of trying it with a 1/2 ton pickup!!!!

[Benelli]

I didn't check it. It's 400 gallons....It's not a fire-truck lol.

I'm running 31" tires.

[Pyrotechnic]

LOL alright then that puts your payload at about 3340 lbs. Being a 4x4 and wanting to haul, I would get a 4.11 gear. Not as highway friendly as what you have now, but it will pull your loads really well and this gives you room to grow as far as tire size.

4.11's will put you at 3000 RPM at 65 MPH.
3.73's will put you at 2700 RPM at 65 MPH.

I would go for the 4.11's since that will bring about the most noticeable change, and your cruise RPM's while fully loaded will be in the meat of the torque curve.

[asphaltburner]

Yo! That's FRANKENTRUCK's (K20) setup,...4.11:1 axles, TH400, twin-stick NP205, and 33" tires.
Kicks butt on the highway,...cruising and passing,...NOT at low rpms! I keep it under 80. Hydraulic lifters protect my investment at extreme rpms. VERY nice accelerator response off the line, too!
In low range, it's a torque monster, especially with the 350 I built.
I'd sure recommend this combination for the chore you have in mind! 31" tires will compliment the combination nicely unless you're heading out on the highway.
Todd.

[Benelli]

If I did decide to go with the higher ratio, probably 4.11, how do I go about doing that? Do I need to find two axles with that ratio, or can I just rebuild the ones I have now?

[asphaltburner]

Ring and pinion gear swap in the axles you have. It does require some micrometer measurements and shimming for a proper wear pattern, so it may be a job you'll want to farm out.
I'd do both axles, but I don't believe that's necessary, and a question I'd like to hear the answer to,...anybody have input on that?
Todd.

[Driveway Dreams]

As far as I know, & can figure. Your front and rears need to have matching ratios other wise when you go in to 4x4 they will be trying to spin at different speeds. And then you will tear stuff up in the driveline.

[asphaltburner]

Yo! Gerald!
That's what I've always thought I remembered (sorry I learned most of this, like, 35+ years ago!),...but you could certainly motor with two different axle ratios. T/case would accommodate, but you'd be working it excessively.
Anyway Benelli, stick with changing axle ratios equally.
Todd.

[LONGHAIR]

Originally Posted by asphaltburner

Yo! Gerald!
That's what I've always thought I remembered (sorry I learned most of this, like, 35+ years ago!),...but you could certainly motor with two different axle ratios. T/case would accommodate, but you'd be working it excessively.
Anyway Benelli, stick with changing axle ratios equally.
Todd.

The only transfercase that could compensate at all would be the "Full-time" NP203, but only in the un-locked position. When locked it would be the same as the others. From the words

I have to put my K10 in 4-lo-loc

we can only assume that this is what you have here. The differential is there to equalize things from front to rear, but I seriously doubt that it could deal with different ratios for very long.....maybe up the driveway into the garage, no farther. Even then you would be better off to put in "loc" and take the drive flanges out of the front hubs.
I would recommend a part-time conversion in any case. Everything about the truck will "feel" better if you do it.

A typical transfercase will not "accommodate" anything. It is either gear-driven or chain driven, but there isn't much room for that. Minor differences happen between front and rear come from factory gear sets...Some of the Dana gears were not exactly the same as the corporate axles that they were paired with. Even these will make shifting the transfercase difficult.


As a "budget consideration" you could swap the rear end to the ratio that you need and just drive it that way until you can afford to do the front. As long as you are willing to convert it to "part-time" and leave it in 2wheel drive, it won't hurt anything.

[asphaltburner]

Yo! Thanks, LONGHAIR!
Wondered about the correct answer to this question but I hadn't pursued it. Others have suggested that different ratios, front and rear could be accommodated by the t/case, BUT, as I suspected, it would be a disaster.
There's a REAL answer for you, Benelli,...and me too!
Todd.

[Benelli]

Part of the reason I put it in 4, as it is part-timed already, is that it'll spin out if I get the one-wheel wonders stuck in some wash outs. It's a pretty tough old hill.

I think I'm going to just leave it as it is, and use my Dad's diesel. More stopping and going power.