I'm pretty sure you can't put any higher than 3.55 in a 1 ton rear end. 3.55 will get you a big improvement, as will a GearVendor Overdrive, they are expensive new, but they never go bad, you should try to find one used, it doesn't matter what it came off of, it will need a new input shaft if it came off something different.

 

3.08 are available for the 10.25" axle.

As far as driveline strength, the best option would be a high number axle ratio and overdrive or double overdrive transmission.

Something like an E4OD with a Gear Vendors behind it would cruise at 77 MPH at 2000 RPM with 31" tires and a 4.30 axle ratio.
That would also give you a very good selection of lower gears on the hills.

The ZF 5 would be very close and give you even more lower gear selections to chose from.

 

After considering all the great info I've received I think what I'll do is this. Exchange the C6 for a fresh rebuild w/ a GV overdrive. Calculations show I should do about 2200 rpm at 70 and I will have 6 different forward speeds, at my command, to use depending on the situation. Yes, it'll be a little pricey but all in all I think it will be worth it. Thanks again for all the info. I'll be sure to let you all know how it works out.

Dennis

 

This might be of interest to you. The reason is it is a big heavy truck that is an 88 made to tow heavy weight. Now considering you are a diesel to their gasser in the article, if you were able to subtract as much heat all over you should see some gains that are respectable for the least amount of money spent. The is project truck example does use the Auxillary OD by GV on it. The article is LONG!

Shedding heat is one way in your orginal post's question of how to keep the trans running well.

http://performanceunlimited.com/projectmpg/

 

Okay.. This is what I did. Ordered a Performance C6 Transmission and a GV overdrive unit. They'll be delivered next week. I should have an equivilent final drive ration of 3.20. This should put the rpm just above 2200 at 70 - just what I was wanting to do. It is costing a little more that I was wanting to spend but what the hay... I think overall it will worth it.

 

By the way, the GV O/D unit will increase in price by 200 buck in April.

 

Power Band. I haven't heard that term in along time. He means the Torque Curve. That is diesel talk.

For a minute I thought we were working on a dirt bike.

 

Yeah, That's what I meant...

 

Hey everyone...
It has been a while since I have posted anything. LONG overdue responses to all the the fantastic advise all of you shared with me. If you'll allow me to bring you up to date. I still have the old uhaul. It is still running great. I went with a rebuilt C6 and a TC with a little higher stall speed. I added a Gear Vendor overdrive unit and for all practical purposes that did the trick. The transmission shifts solid and with the right physical placement of the switch on the GV unit you can go easily through 1,2,3,4,5,6 different speed and on flat ground peg the speedo (85 mph) running at 3700 RPM. Long hills are a problem but I can maintain 55-60 with a reasonable load in the box. I'll get 8 to a little over 11 MPG depending on the wind at highway speeds which I don't consider to be too bad at all.

I followed all the instructions to replace the heater in the fuel filter housing so I appreciate all that advice too.

Now I am thinking about opening up the exhause a little as I am sure that huge old stock muffler under there probably slows me down a bit.. That and probably getting some advice on how to get around that last 10 gallons and fifteen minutes of fueling time cause by foaming diesel fuel.

Thanks again!

 

I *really* suggest getting a Banks Sidewinder turbo for it. You can probably pick one up used for around $500, and as long as the wheel has no play, you're probably golden.

I've put one on mine, and it really helps with the 1800-2400RPM range - especially as I'm a bit up in the mountains at 2000 feet, where the air is less. Not only does the engine just plain sound better at higher RPMs, but it has much better power and acceleration. It also improves mileage signifigantly:
In my truck, stock, I could maby get 12mpg with 4.10s and a 5-speed, going eh... 65.
I added a GVOD, which brought cruising speed to 1600, and I was able to get around 16-17, going the same speed... but in top gear, I had almost no power. I'd be hard pressed to go up a long, decently steep hill without downshifting.
I recently added a turbo, and upped the fuel somewhat. I recently drove 300 miles at ~74MPH on the highway, got 18MPG.
The power it has however... I can cruise up the same hill I had major trouble with before... and /accelerate/ in top gear.

I also tried it with ~3200lbs in the bed. I was still able to roar up the hill, accelerating as I went, but I had to back off a little near the top due to my EGTs hitting 1000.

As you're starting from a heavier vehicle(mine's just a regular extended cab), I suspect you'll not see quite as good mileage, but the extra turbo power will really help.


Also, muffler wise, I found that my turbo plus a Thrush Welded 3" muffler(flowmaster 40 clone, apparently) keeps the noise down, gives a good sound, and doesn't appear to reduce power compared to straight-pipe.

 

The thought of a turbo has crossed my mind.. I live at about 5800 feet. Around town, on flat ground the old truck runs pretty good. In September I took a bunch of stuff over to Indiana, about 700 feet, and I could really tell the difference so a turbo would definitely help around here.

My fuel tank is mounted on the side of the frame, just past the cab; a 30 gallon tank with a short filler neck about 2-1/2" in diameter. When I fuel up the fuel will start foaming up the neck and shut the nozzle off even though the tank is only 2/3's full. That last 10 gallons is a real pain and takes about 15 minutes to fill it to the top.

Is that the nature of the beast or is there some modification of sorts that can help to eliminate this problem?

In the meantime I'm looking around for a used turbo..... Thanks for the comeback and I'll be checking with you soon....