GV or U.S.gear overdrive

[mike g]

I am looking for some input on how well these units shift when splitting the gears? I really need to get one of these in the truck for the 2-3 spread and the dreaded 5th gear problem. I have 3. 55 gears and the 5 speed and will need to split quite a bit with camper and hot rod in tow.

Thanks Mike

 

[Powder Extreme]

I had a US Gear unit, I really liked it. It's the only one that will allow you to use 4 wheel drive. Also you can't put the Gear Vendors in overdrive and leave it there. I really liked that with the US Gear, when empty I would leave it in overdrive and just use all 5 gears in the transmission. Splitting gears is a little tricky, but once you learn the technique it isn't too bad.



Jerry

 

[Texas Diesel]

Just a thought, I saw new NV-5600's for less than $3000 and you get tho keep your 4500 as a spare or sell it.

 

[Floor It]

I have a GV and love it. Its set up to work in 2-wheel drive mode only,I couldnt see the need to use it in 4-wheel drive. It also saved me from having to lenghten the front drive shaft too. You cant use it with an exhaust brake but then why would you be in the overdrive mode when your trying to slow down. Its a good unit,IMO.

 

[Reb.B]

k, here's the deal on the over-drive units. GV uses a clutch pack design. The gear venders unit bolts up after the tranfer case which shortens your rear driveline and does nothing with your front drive line. It only works in 2-wd. U can still use 4-wd but can't turn the unit on. They work very well with automatics, but here is the key, ... . u can NOT use a exhuast brake with a GV unit or it will grenade. GV will not warrenty a GV unit if u have used a engine brake.



The U. S. gear unit uses a gear design and it bolts up between the tranfer case and the transmission. U have to shorten the rear driveline and lengthen the front drive line. U HAVE to let off the throttle for the unit to shift. U CAN use the exhaust brake with this unit.



My opinion was if u have a auto, go with GV and if u have a standard, go with U. S. . The way autos are performing these days, U. S. gear MIGHT be the unit for both. Both say that they will handle 30, 000 gvw, (i think). I believe the the U. S. unit is stronger though and will not get as hot. Hope this helps, take it for what it worth, ... . reb

 

[Doubleclutch]

And for my two cents... if you're counting the granny gear as first gear, you'll be dissapointed at the 2-3 split. The rear wheels must be travelling around 25-30 miles per hour to generate the 600# hydraulic pressure inside the GV box, the 2-3 split takes a long-long time. The 3-4 gear split goes like this: > 2000 rpm in third, knob up, one, two, three, four, clutch in, clutch out, and you're ~ 1500 rpm. The 4-5 split is much faster since the internal pressure is already up. The exhaust brake issue is easily solved by interrupting the exhaust brake power through the GV switch on the stick. The exhaust brake switching I'll explain if you head down the GV road. Greg

 

[Paul]

One other piece of info. If you have a standard length wheelbase and a 4X4, to use a US gear you must modify the fuel tank. That is one of the main reasons I chose the GearVendor.

 

[mike g]

Hey guys,

Thanks for all of the good info. It sounds like the u. s. is the direction that I should be heading since I have a exhaust brake and my truck does not even see20 -25 mph until it is in 3rd gear. It would defeat the purpose if I could not split the lower gears where I need it the most.

Thanks Mike

 

[jhurst]

Hey



Does US Gear have a website? Where did you guys buy your unit at?



Justin H.

 

[LarryB]

here's my $. 02

http://216.235.147.117/forums/showthread.php?s=&threadid=39900

 

[GLASMITHS]

DOUBLE OVERDRIVE

There is some posts above that state that you can not engage a Gear Vendors in O/D. DUH, We unplug a lot of stuff along the way to having a great truck, right. So why not unplug the lock-out for o/d on the GV box?



I just replaced mine at 74,000 miles, using a PAC Brake. GV told me that was probably my problem, using it to gear down. I listened to my installer and did not read all the booklet . I do not run under 65mph with both o/d on though. With my set up it gives me about 1950 rpm at 72mph UNLOADED on the Interestate and is very quite. Just Hummin

 

[michaelmurray]

For those of you with automatics, can you explain the shift process when in automode? The way I understand it is that is it requires no operator intervention. The unit automatically shifts, but is that for every gear shift or only when the engine is loaded? Also, I understand you can wire the exhaust brake switch inline with the GV to prevent the exh brake from activating when the unit is in overdrive. It sounds like a sweet system to me for the guys with autos. Do the autos have the 4 second delay when shifting, or does it shift smoothly like the automatic trans? Thanks.

 

[GLASMITHS]

GV shifting with Auto

From my point the GV is made for auto with 410 rear end. It keeps the rpm right at about 2000 at legal speeds, so... .



In auto mode it shifts into o/d (GV) at 40 mph. There is no waiting period. This is part of the reason I went with the GV. You can shift under full power; up or down. It is not a "smooth"

shift; more like a locked to lock I try to let up just a tad, and most of the shifts are very smooth. We are now using a full synthetic and it is much smoother than with the old dino oil from GM.



The upshift in auto mode is speed related, no matter what gear you are in. It is one time. If you are gear splitting, it is better to keep it manuel. You do have to change between each gear. It sounds like to me that 4 seconds would kill your rpm?

 

[Shooter]

With my auto I only use the GV for 3rd ( direct ) . In direct and GV od I run 75 at about 2250 which will pull any grade < 8% at 75 mph and egt's at 1250. The GV has a lockout input so if you are in 4x4 or the exhaust brake is energised the unit will not allow an overdrive shift. I have never tried em but they are there. IF I am decencing a grade at 75 I will use engine brakeing or slow to 65 and shift out of GV od and let the exh brake do its thing.



If I had a std trans I would go with the US GEAR.

 

[Utah Willie]

GV or US Gear

I have a US Gear behind my 5 speed and an E-brake. I run the US Gear O/D at any time... . and on long decents where steep isn't a real problem, the 4th over works great and if unloaded... . 5th over. I love the unit. It's been on for 40K+ and no problems. Splitting gears is not easy, but becomes that way with practise... . once you get used to the "CLUNK" of the gears. I love starting out in 1st direct and going through all ten speeds... ... you'll also love that little difference in the splits that keeps your RPM constant on the downhills.

 

[mike g]

That is what I would like to do I was wondering if you split the gears under heavy towing at low speeds can you do it without losing all of the momentem that you have. Can you split 2-3 without the truck stopping with the weight and grade?

 

[GLASMITHS]

GV at low speeds

Mike:



I asked GV lately about that. They said, and I know from experience, it will not engage before 20mph, and you can tool along in first or second all day. They say it needs the 20mph to build the 600psi; additional speed does not matter. Meaning you cain't lug the GV.

 

[Powder Extreme]

The US Gear shifts almost instantly when you flip the switch. I had a push/pull switch installed on my gearshift. I drive semi's as well, and the US unit is very similar to splitting in a big rig, although you don't "preselect" like you do in a truck. The shifting definitely takes practice to get it smooth. Splitting while downshifting is the trickiest in my opinion, but with a little practice you'll get good at it.



When I first installed my unit, I ran synthetic in it. When I rebuilt it around 50 or 60k we decided the synthetic was making it almost too "loose" We switched to 80w 140 regular oil and it shifted much smoother.



I was never disappointed in my US Gear, and 85mph at an even 2000rpm sure makes for nice cruising. Not too mention I would still get around 19mpg at that speed.



Jerry

 

[redram]

Originally posted by Texas Diesel

Just a thought, I saw new NV-5600's for less than $3000 and you get tho keep your 4500 as a spare or sell it.

But most using a splitter want an overdrive for highway towing. The six speed is nice, but the final gear ratio in 6th is close to what the NV4500 in 5th is. Correct? The NV5600 reduced the split in gears but did not change the final drive.



JMHO.