I'd like to hear from anyone out there that has one of these. I am considering getting one for my Dodge. When I bought the truck, I didn't think I'd be doing that much towing, but now there always seems to be something tagging along behind me, and they keep getting bigger! Needless to say, the 3:55 gearset was a mistake, and I don't want to change the gears, or rearend out.

 

I'm in the same boat, need a 4:10 for towing my 5fer but like the 3:55, running light. I priced a underdive unit that would give me about 3:90 ratio engaged. Its about 2 1/2 times the cost of the rear. I too would like to hear from someone who's done it.

Dave

 

I just checked on the price from US Gears, and it was $2800. It has a 1:25 underdrive, and if my math is correct, that would make a 3:55 to around a 4:40, quite a difference. That would give me all the grunt I need, for taking off, then once I hit final drive, I can shift it back to the 1:1 ratio, that's if I'm understanding it correctly.

 

Your right, My calculator must have screwed up. The RPM's with my tires is 200 more in OD than a 4:10 rear would be. I'd guess at 4:30 or so with my six speed's final ratio in OD of 3.23 with the underdrive, instead of 2:58 with want I have now.

Dave

 

Is no one out there using one of these units?

 

Hello,

I have buddy who has a 97 dodge 12 valve and a 5 speed with a gear vendors under/over drive. I have driven and pulled about 8,000 pounds with it. There is alot of shifting but the cool thing is that the aux tranny keeps the engine in the power range so you are never lugging or really wrapped up. Which really helps the fuel economy and wear and tear on the engine and EGT's, his truck also has the 3.55 gears in the rearend. When your unloaded you can put the truck in fifth over and cruise at a really low rpm, or run over a hundred at regular rpm. As for other makers of aux trannys i do not know much about them as I have only been around this one truck with a splitter. I believe he payed about 3,000 dollars installed. hope this helps.

Ty

 

have not used a US gear piece but if u have a 4x4 it is designed to go betweem tranny and tranfercase big expense for install gear venders makes a unit probably wont do what u want cause they dont have a true underdrive but it will bolt on behind the tranfercase if u have a 4x4.

 

I have heard of prices over 2k not including installing the units. I visit a RV forum and there is talk about them alot. I thought about it for a short time but plan on installing a Tranny.

KC

 

yep, have one on my Suburban with the 6.5 Turbo Diesel. The truck had 4:10 gears and I hated it sreaming on the highway. Used it as a splitter and an overdrive. The truck has a 5 speed and there is a HUGE gap between third and forth. I split 3rd and 4th with it while towing, and I allways use it in 5th gear overdrive while running empty. Final gear ratio with 5th and overdrive is 2:21 !! 75 MPH, 1,800 RPM, its a beautiful thing....

BUT.... the reason you are not finding many people on here with them is simple WAY WAY WAY too much $$$$$$$$. I got mine at an auction, un-used for $600. Now for that its wonderfull, for $2,800, I think you would need your head examined....

Zino

 

cstmfabman:

I have the Gear Vendors unit on my truck the last 95K miles. I have an auto like you. For an auto the unit works best as a double overdrive above 55 mph. At 70 mph the RPM's are 1,500 versus 2,000 with the unit turned off. Increases the MPG by about 3. Have not had any problems with the unit.

If you had a standard transmission the unit would be good for towing as it splits each gear, but in an auto, IMO, it is good for overdrive only.

If you want more details, go to www.gearvendors.com and ask them about the unit. They will respond to you within a few days.

Zino:

You have to consider the reduction in noise, increased mileage, and less wear on the engine and drivetrain. I want my CTD to go a million!

John

 

[quote author=cstmfabman link=board=7;threadid=18843;start=0#msg177141 date=1061954545]
I just checked on the price from US Gears, and it was $2800. It has a 1:25 underdrive, and if my math is correct, that would make a 3:55 to around a 4:40, quite a difference. That would give me all the grunt I need, for taking off, then once I hit final drive, I can shift it back to the 1:1 ratio, that's if I'm understanding it correctly.
[/quote]

You are about correct....

This ratio thing depends on which way you are looking at it. I looked into the US gear unit a while back and you will find that the OD ratio is a .75 ratio. See depending on how you do the math it will come out as either 1:25 or :75. Another post related the 500 rpm drop which is the :75 OD ratio. Actually the .75 OD comes out to around 600 rpm drop. 1:1 is no OD and anything below 1:1 is an OD ratio. 1:25 would be a reduction not an OD. The 1:25 would be a reduction of the same gearing as a .75 OD, in other words the gears backwards. You can get the unit either as an OD or a reduction unit or UD. The ratio is the same either set up as an OD or a UD.

On the five speed it would make some splits but on the six speed the ratios are too close to a gear change to make real splits, so it is used as just an OD or a UD giving either one lower gear or one higher gear.

I give you something to think about, if you have an automatic the UD unit will just about give you the same ratio as the automatic in direct (no OD). Of course it will give you a lower first so actually another gear on the bottom.

The unit set us as an OD will give near the same ratio improvement as the standard OD in the transmission, giving you another gear on top.

To figure it if it is an OD unit multiply the ratio by .75 and if it is an UD unit, devide the ratio by .75