I was reading about the gear vendor for my 78 NP 435.The more I read about it the more I like it!I was thinking The gear vendor and some 4.56 gears that will be about 3.3 in the GV over drive. How good do the hold up under sever abuse? Why is their no 1st over, 2nd over it the unit is just turned on and off?How hard are they to intall?
thanks,
dustin

 

I have the GearVendors behind the NP205 transfer case in my '74 hi-boy, with 4.10 rear. It's definitely an asset to allow you to slow things down in the drivetrain on the highway. I'm running between 22-2400 RPM at highway speed in OD, and it really quiets things down, and 3rd Over is an awesome hill-pulling gear! They advertise that the unit can handle up to 1100 HP, used in motor homes, dragsters, you name it. Because it's based on a planetary gear, they should be pretty bomb-proof. I've got less than 10,000 miles on mine so far, so can't speak to longevity, and I'm not hot-rodding much, mainly drag around a slide-in camper and beat around some back country.
The reason you can't use 1st Over is that the OD engages via hydraulic pressure generated by a hydraulic pump in the OD unit. They figure you won't be making enough speed to make sufficient pressure to keep it engaged. For the same reason, they recommend against using 2nd Over for compression braking.
My install took me nearly a day, not including measuring the driveline and getting it cut to match afterwards. Mechanically it's pretty straight-forward to install, but I fiddled with the wiring portion to try to keep it as neat as possible. Also, I found I had to get them to provide a 90degree speedo adaptor because it was too close to a side gas tank to make the bend. But they were very good about consulting on any issues I had, and didn't quibble about a couple of things besides the speedo that I wanted taken care of. Good outfit.
Steve

 

How is your gasmileage performance since you installed it? Before and after?

Thanks, Rb

 

Rb,
I installed a newly built FE410 at the same time I installed the GV, so can't ascribe increased gas mileage to one or the other. The 410 is a lot torquier than the low compression 390 it replaced, so I am able to run with the GV engaged most all of the time on the highway. That has to help mileage, but can't say with authority how much. I can tell you that with slide-in camper aboard, before I was usually looking at about 6.5-7 mpg, and now it's between 7.5-8, so definitely better.
Guess I'd have to say that what I appreciate the most is that the noise level in old hi-boy is much less, I can even hear the stereo if I choose, and the wife too, even if I don't choose sometimes! And running neck and neck as the most appreciated thing, is that I can run up just about any hill in 3rd OD without losing speed, where before I would have to feather back a bit to keep revs under control in 3rd for long sustained climbs. Gads, I'm starting to sound like a GV salesman here! Wonder if they would give me a commision after the fact?
One last tip, I got a 10% discount by joining the Camping World President's Club for $20, a pretty good payback on the $2650 GV!!
Steve

 

I found a used Gear Vendors in a 2wd F350 with a C6. I'm wondering if a GearVendors for a C6 2wd can be converted to go behind a BW1356 instead?? I don't know how much they want for the overdrive or what condition it's in, just thought maybe that could be a cheaper alternative to buying a new one. I saw a used one for a TH400 2wd and they were asking $2400 for it. For that price, I'd just get a new one!

 

The basic GV unit is the same for all installations, but they have a different adapter for all the types/brands of gear box they fasten to. I don't have any idea how bad GV would nail you for all of the components required to adapt from one to another, but there are a lot of itty-bitty pieces which are part of the package. They are decent to talk to, so you might just give them a call and find out. You're pretty much captive to sourcing from them in any event.

 

Thanks Stephen, I kinda thought it might be something like that. So far I haven't called on the used unit yet either.