F350 - two speed rear axle? - Diesel Forum

koalamotorsport · 12-22-2007, 07:59 PM

Is there a two speed rear axle available?
Powerstroke 1995 5spd F350 roll-back tow truck. Not sure of the rear end ratio, but it turns 3000rpm at 70mph. I use it for mostly long hauls, so it would be nice to have a 2 speed rear axle to get the revs down to around 2000 at 70 but keep the low end grunt.

Thanks

Brett

bosefes · 12-22-2007, 08:03 PM

Most of the two speed rear axles you'll find today are gonna be way to big to put in there. Have you thought about a US GEAR Overdrive?

mlcowden · 12-22-2007, 08:53 PM

There was a recent discussion on this in the towing section below last week.

koalamotorsport · 12-22-2007, 10:13 PM

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: StarJM</div><div class="ubbcode-body">There was a recent discussion on this in the towing section below last week. </div></div>
Thanks, just found and read that thread. Seems the Gear Vendors unit would be the trick, but it's pricey. It would allow me to keep the rear disc brakes though, which I'm sure I won't find on a 2 speed axle.

Brett

koalamotorsport · 12-22-2007, 11:07 PM

Actually, reading through the entire Gear Vendor site, it might be less pricey than it seems. They claim 22-28% fuel savings. At 22%, it would only take about 8500 miles to pay for the unit in fuel savings, assuming $3.25/gallon (I was paying $3.40/gallon 2 days ago on a 900 mile trip)

Thanks for the point in the right direction.

bosefes · 12-22-2007, 11:31 PM

You may want to ask around to people that have actually towed heavy with a gear vendors. I think you'll find that many have had a lot of breakage and other problems with it. Do some research on the Gear Vendors option as well as the US Gear Overdrive. The US Gear unit seems to have a much better track record.

mgraveman · 12-23-2007, 01:42 PM

Have you considered just changing the rear end gears? If you never pull and aren't loaded over GVW a set of 3.55 gears and 235/85R16 tires will be enough to get you going, and will help a lot on the highway.

JoeBob1901 · 12-23-2007, 02:16 PM

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Koala_Motorsport</div><div class="ubbcode-body">Actually, reading through the entire Gear Vendor site, it might be less pricey than it seems. They claim 22-28% fuel savings. At 22%, it would only take about 8500 miles to pay for the unit in fuel savings, assuming $3.25/gallon (I was paying $3.40/gallon 2 days ago on a 900 mile trip)

Thanks for the point in the right direction. </div></div>

You sure about that? Can you show the equations on how you got to that figure? 8500 miles at around 15mpg would cost roughly 2k to fill up, so a 20% savings would be roughly 400?

I've looked at the gear vendors, they seem nice, and would be great if you haul quite a bit and have deep gearing, but seem to be pretty pricey, if it was in the ~2000 range, I think it'd be much more economical.

johndeere9610 · 12-23-2007, 07:38 PM

I think I would try to find some 3.55 gears

TECH51 · 12-23-2007, 08:08 PM

I don't know about 3.55 on a rollback with two cars or trucks hooked up mite be a dog.

johndeere9610 · 12-24-2007, 12:14 AM

I dont know about a roll back with to cars on doing 70 to ofthen either but thats what he wanted was 70mph @ 2000 rpm.

Not trying to me a smart a$$
Rusty

mgraveman · 12-24-2007, 01:07 AM

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: JohnDeere9610</div><div class="ubbcode-body">I dont know about a roll back with to cars on doing 70 to ofthen either but thats what he wanted was 70mph @ 2000 rpm.

Not trying to me a smart a$$
Rusty </div></div>

He never said anything about two cars. We have no idea how he is using it.

TECH51 · 12-24-2007, 01:18 AM

DAMM I just stated that towing with 3.55 mite not the way to go? Sorry if you think I was calling you a smart a$$.

koalamotorsport · 12-24-2007, 09:58 PM

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: JoeBob1901</div><div class="ubbcode-body">
You sure about that? Can you show the equations on how you got to that figure? 8500 miles at around 15mpg would cost roughly 2k to fill up, so a 20% savings would be roughly 400?
</div></div>

8500 miles at an average of 7.5 mpg is 1133 gallons. 1133 gallons at $3.40 is $3853. I seem to have dropped the next part of the equation, sorry. 22% of $3853 is $850, so I guess it will actually take 35K miles.... Oh well, thanks for waking me up.

Brett

koalamotorsport · 12-24-2007, 10:00 PM

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: TECH51</div><div class="ubbcode-body">I don't know about 3.55 on a rollback with two cars or trucks hooked up mite be a dog. </div></div>

Agreed, which is why I don't want to do that. Although, the other option is more power, then taller gears. The Banks kit that adds 250+ lbft of torque is intriguing. That, combined with 3.55 gears will likely give me same acceleration, but better cruising. Right now, the truck takes some work to get it moving with 2 cars on board, which is how I usually run over-the-road.

Hmm, maybe the Banks kit, 3.55 gears AND an overdrive unit... It's only $$$$

Brett