Engine/Transmission (1994 - 1998) gear vendors upgrade for NV4500

[KBurgoyne]

anybody put a gear vendors over/under drive on your NV4500. is it worth the money. what are your driving impressions?.

 

[hsmith]

I guess it depends on what you expect for the money. Definitely a large investment. I have had mine for almost 200k miles now. Really like being able to split while towing. It is a smooth operator for sure, however you will never be able to justify the cost as a saving, no matter how much you drive. It will never pay for itself in fuel savings.

It is a hydraulic unit and will not engage below 20 mph and does not like being loaded in reverse.

I have not been able to get over 60k on one before it gave up. Consolation is their exchange policy is very reasonable, around 20 percent of total original price.

I'm not into bashing anyone's products but this is what I have been through with mine.

 

[KBurgoyne]

3 grand for something that will only last 60k sounds like a bad deal expecially when a ring and pinion would cost about around 1500 parts and labor and would last forever. i know i would lose some towing ability with a higher gear set, but money talks.



thanks for the info hsmith.

 

[DonTX]

I would refuse one if it were free. I had one in a Cummins 5. 9 motorhome behind an Allison. It shot craps at 15k miles, took forever to get parts to fix it, sold the motorhome the day I got it repaired.

3 grand for something that will only last 60k sounds like a bad deal expecially when a ring and pinion would cost about around 1500 parts and labor and would last forever. i know i would lose some towing ability with a higher gear set, but money talks.



thanks for the info hsmith.

 

[hsmith]

I have to add I have never had any problems with them on getting replacement units in short order. Last time we were a long way from home and they sent me one asap to the rv resort we were staying. With the driveshaft removed, it is probably only a 45 minute job to replace.

 

[Loren]

Kburgoyne,



I don’t have a GearVendors unit, but years ago I installed a U. S. Gear overdrive on my 2000 model year truck. I wrote an article for the TDR that was published in issue #47, page 162. I would recommend you read that, since it’s much more detailed than what I can write here.



Here are some of my thoughts:



I went with the U. S. Gear instead of the GearVendors mostly because the U. S. Gear unit will work in 4WD. The GV mounts to the rear of the transfer case and does not change the ratio to the front drive shaft, so it is locked out whenever you are in 4WD.



I also wanted the manual shift of the U. S. Gear unit, although I’ll admit that I have never driven a GV.



As I said in that article, an overdrive installed on a five-speed transmission is probably a much better investment than converting the truck to a six-speed.



At the time I wrote that article, diesel fuel was selling for about $1. 70/gallon. (Oh, for those prices again. ) With that price for fuel, the savings in fuel cost would essentially never pay for the cost of an overdrive unit. If you put on really high mileage, like over 30,000 miles/year, you may save money, even at today’s fuel prices.



I really liked my overdrive and considered it to be the best accessory I added to that truck, with the exception of the exhaust brake. I would encourage you to do it.



– Loren

 

[SRehberg]

I bought our truck used and it came with the GV OD already installed. I personally don't like it. One thing to consider is the use of an exhaust brake with the GV unit... . not recommended by the manufacturer due to "reverse torque. " I was told by GV's tech to avoid downhill grades using just the engine as a way to hold speed down (no exhaust brake) while the GV unit is engaged. They told me the braking action would destroy the cone clutch. Basically I've used it with the truck when not towing and it does drop the RPM to a quieter level. Our truck is a 4x4 so it hangs on the rear end of the transfer case and connected to the rear axle with a one piece driveshaft which gives vibration at 50 mph. Some ding dong decided a one piece shaft would be better than shortening the two piece version which would have given more stability. We tow with a 5th wheel and the GV OD is never used when towing, just 5th, 4th etc. I'd like to find a good two piece drive shaft and bearing setup.

 

[hsmith]

Mine being a 2wd, the GV is a direct mount and I have zero vibration issues. Stayed with the two piece drive shaft. I use mine all the time towing, 4th over is my primary towing gear because 5th gear is so weak in the 4500. I have mine wired so that the eb will not work when the gv is engaged.