Auxillary OD
10-19-2006, 06:00 PM
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Auxillary OD
Is anyone running an auxiliary overdrive unit? I did a search but found nothing on this subject.
It seems they would be good for gear splitting or lowering the RPM when not hauling. I calculate I would drop my RPM to 1600 at 70 MPH with a 20% OD which is the peak factory torque rating so it should handle the gear.
Just curious about other opinions.
It seems they would be good for gear splitting or lowering the RPM when not hauling. I calculate I would drop my RPM to 1600 at 70 MPH with a 20% OD which is the peak factory torque rating so it should handle the gear.
Just curious about other opinions.
10-29-2006, 08:13 AM
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I found this article the other day. Hope this might help.
B.
http://truckworld.tenmagazines.com/t...id=2798&sid=42
B.
http://truckworld.tenmagazines.com/t...id=2798&sid=42
10-29-2006, 08:44 AM
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I have the Gear Venders unit on my ’05 with the 6-speed G56. It won’t give you 30 MPG. I just couldn’t handle one more highway trip running 2000RPM at 62.5 MPH or 2300 at 75MPH. I’m sure the Cummins could run the rest of its life at 2500RPM with no problems, but those RPMs aren’t needed when not towing.
Now I have 10 forward gears and can shift like a real Billy-Big Rigger.
75 MPH is 1850 RPM in 6th over. 70MPH is around 1750 RPM (Below are the gear ratios). 60MPH is about the slowest you can do in 6th over before the RPMs drop too much. 5Th over is great however because it is 1% faster then the stock 6th gear and you are sending power straight through the transmission, so it should work out good for towing.
I’ve done one highway trip with this puppy and averaged 20.2 MPG (hand calculated
) running with traffic at anywhere from 70-80 MPH (you know how the interstates are) with 3 adults and a bed full of camping supplies plus some tooling around in the woods. This was running ULSD with Power Service/MMO. I think it was a winter blend too, but don’t quote me. Previous trips before the GV unit at 62.5-65 MPH yielded 19.7 MPG with summer fuel. (Mix of ULSD/LSD PS and MMO). So MPG is similar, but I can go faster.
I have the ROKK sensor mod too, I think that got me .5 MPG.
1st 6.29
2nd 3.48
3rd 2.1
3rd over 1.64
4th 1.38
4th over 1.08
5th 1.00
5th over 0.78
6th 0.79
6th over 0.62
If you have any more questions just ask.
Now I have 10 forward gears and can shift like a real Billy-Big Rigger.
75 MPH is 1850 RPM in 6th over. 70MPH is around 1750 RPM (Below are the gear ratios). 60MPH is about the slowest you can do in 6th over before the RPMs drop too much. 5Th over is great however because it is 1% faster then the stock 6th gear and you are sending power straight through the transmission, so it should work out good for towing.I’ve done one highway trip with this puppy and averaged 20.2 MPG (hand calculated
) running with traffic at anywhere from 70-80 MPH (you know how the interstates are) with 3 adults and a bed full of camping supplies plus some tooling around in the woods. This was running ULSD with Power Service/MMO. I think it was a winter blend too, but don’t quote me. Previous trips before the GV unit at 62.5-65 MPH yielded 19.7 MPG with summer fuel. (Mix of ULSD/LSD PS and MMO). So MPG is similar, but I can go faster. I have the ROKK sensor mod too, I think that got me .5 MPG.
1st 6.29
2nd 3.48
3rd 2.1
3rd over 1.64
4th 1.38
4th over 1.08
5th 1.00
5th over 0.78
6th 0.79
6th over 0.62
If you have any more questions just ask.
10-29-2006, 05:03 PM
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I just put the GV unit on 3 weeks ago and haven’t towed anything with it yet. I think the book says it is rated for 24K gross.
Our stock transmission output yokes and U-joints are large compared to the one the GV unit has. The GV unit uses a Spicer 1350 yoke and U-joint.
When I ordered the GV unit I ordered a bran-new driveshaft complete with yoke, rear flange, both U-joints and center section all balanced from like $175 from dodgeparts.com I believe. I took this new driveshaft and the GV yoke to a driveshaft shop where they cut it down, put on a Spicer 1350 U-joint on the front and balanced it for me.
It gives you 10 forward gears (with a manual), really 9 for towing because you won’t want to use 6-over for towing for I think you would toast your high gear. You should be able to put the RPMs wherever you need them to match any speed.
Towing 27K? Well, here is what I don’t like:
The smaller front yoke and U-joint, however I’m sure they can handle it.
Increase driveline U-joint angles if you have 1-piece driveshaft. (This could be addressed if you really wanted to)
Any OD unit induces a moment on the rear of the transfer case and the back of the transmission that was never there before.
The planetary gear design of the GV unit is pretty stout however.
Our stock transmission output yokes and U-joints are large compared to the one the GV unit has. The GV unit uses a Spicer 1350 yoke and U-joint.
When I ordered the GV unit I ordered a bran-new driveshaft complete with yoke, rear flange, both U-joints and center section all balanced from like $175 from dodgeparts.com I believe. I took this new driveshaft and the GV yoke to a driveshaft shop where they cut it down, put on a Spicer 1350 U-joint on the front and balanced it for me.
It gives you 10 forward gears (with a manual), really 9 for towing because you won’t want to use 6-over for towing for I think you would toast your high gear. You should be able to put the RPMs wherever you need them to match any speed.
Towing 27K? Well, here is what I don’t like:
The smaller front yoke and U-joint, however I’m sure they can handle it.
Increase driveline U-joint angles if you have 1-piece driveshaft. (This could be addressed if you really wanted to)
Any OD unit induces a moment on the rear of the transfer case and the back of the transmission that was never there before.
The planetary gear design of the GV unit is pretty stout however.
10-29-2006, 06:15 PM
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I was looking over the quad 4x4 web site and read this article about transmission failures. About half way down the page.
B
http://http://quad4x4.com/Causes%20o...20Failures.htm
B
http://http://quad4x4.com/Causes%20o...20Failures.htm
10-29-2006, 06:42 PM
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10-29-2006, 07:51 PM
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So they should be a good thing for me then I am thinking, if it handles that much power. I wonder if they would be any good for drag racing?
Kevin
Kevin
10-29-2006, 07:53 PM
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Yes, the GV unit will work with automatics; they even have an “auto” shift mode for the automatics.
Interesting article on transmission failures. I’m not familiar with the NV4500 setup; however with the G56/NV271 setup I think the weakest point would be the rear half of the NV271. But what do I know? I just drive the thing.
High horsepower and the GV? Well, maybe we should find sled-puller to try one out and see what breaks??!! (Well they’d have to pull in 2WD for this sucker is behind the transfer case and only overdrives the rear wheels) The G56, the GV, the Spicer 1350, or the NV271? It sure won’t be the Cummins breaking, lol.
Interesting article on transmission failures. I’m not familiar with the NV4500 setup; however with the G56/NV271 setup I think the weakest point would be the rear half of the NV271. But what do I know? I just drive the thing.
High horsepower and the GV? Well, maybe we should find sled-puller to try one out and see what breaks??!! (Well they’d have to pull in 2WD for this sucker is behind the transfer case and only overdrives the rear wheels) The G56, the GV, the Spicer 1350, or the NV271? It sure won’t be the Cummins breaking, lol.
10-29-2006, 08:02 PM
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The gearvendors site talks all about drag racing. The planetary setup lends well to lots of high load shifting. The GV setup isn’t cheap however. You are looking at $3K for the unit and a few Benjamins to modify your driveshaft. It was easy to bolt in, however it took me a while to wire it up since I like to take care with wiring.