Extra Gear

[6.5 Detroit Diesel]

Hmm.. I've been reading a lot about the Gear Vendor setup. Seems like a lot of people are doing it. My question is, can I safely add another overdrive gear onto my truck? Transmission is a Five speed, (L,1,2,3,Od) I wanted to put an International 6+ in, but money isn't there right now.

[Craig M]

The quick answer is yes. The new Duramax has an Allison with a double overdrive, which is what you will have with a gear vendors behind a 5 speed manual with OD 5th. You rear end is 4.10, not sure what overdrive your 5 speed has. Main advantage to double overdrive is high speed driving. RPM's will be kept down at high (70+) miles per hour. You will also have the ability to engage the Gear Vendors on any of the other 4 gears if you wish. 4th over may not be that much different than 5th direct, but you would have that option.

[moondoggie]

Good Day!

"...can I safely add another overdrive gear onto my truck?" I'm not sure what would make it unsafe.

My 95 pickup (see signature) has a 4L80-E, which has a 0.75 OD ratio; the Gear Vendors Aux. OD on this truck has a 0.78 ratio. This gives ~ 1850 rpm @ 70 mph with stock-sized tires. This puts me right on the torque peak (supposedly where best mpg is found), & oh my! is she quiet.

Blessings!

[6.5 Detroit Diesel]

Not sure what the gear ratios are. It's basically a four speed. The low gear I only use when starting loads. What I want the extra gear for is to as mentioned, bring down my rpm's at highway speeds.

[Dvldog8793]

Howdy
The Gear Vendor is a SOLID product with a seriuose reputation. They ain't cheap, but I think you get what you pay for. My trans runs cooler when towing in third with GV engaged. Supposedly the GV is rated for more power than the 4L80E. I would think that with a 5 speed you could really use it. I don't know if my GV will ever pay for itself but it is nice to cruise down the highway and also be able to the house behind me if I want.
L8r
Conley

[moondoggie]

Good Day!

If you're serious about a Gear Vendors, keep in mind: it only works above a certain minimum speed (18 mph?). It's actuated by a pump driven internally by the driveshaft, so must be at a minimum rpm for the pump to make enough pressure for it to work right. If all you're doing is dropping highway rpm (what I use it for), & not splitting gears, no problems.


Blessings!
(signature in previous post)

[JohnC]

IIRC the OD in the NV4500 is 0.71:1