Gear Vendor or not

[ronman]

I didn't consider the installation to be difficult, but, this is the second truck I've installed one on. First time thru in '98, it took me a bit longer. This time it was much faster since I was familiar. To minimize the down time of the truck, I'd recommend installing the electronic controls first because that work won't immmobilize the truck. Once they're in, install the OD unit, take your driveshaft measurement (I triple checked mine... ) then get the driveshaft cut/balanced.

 

[HCanales]

I finally have my GV installed!! My next question is can I get away with a single piece drive shaft? I read the book and it says you can as long as you're under 60" from U-joint eye to eye and mine measures exactly 58". I wounder is the margin starts at 60" or if its plus or minus 2"? My theory on this is; less moving parts and cheaper on joints with only two. I don't want to make a barber shop pole out of my drive shaft if this won't work. Anyone try this yet?



Also, 1350 yokes seem a bit smaller than the stock AAM yokes, especially when you look at the U-joint cap size difference. If thats what GV suggest then I guess thats good enough

Thanks

 

[ronman]

I'd suggest you call GV's Tech support and ask them. They have lots of experience and can make the call on size. Agreed, the yoke that GV supplies is a lot smaller/lighter then stock, but it works fine. I had well over 100K miles on my '98 GVOD with no U-joint issues.

I finally have my GV installed!! My next question is can I get away with a single piece drive shaft? I read the book and it says you can as long as you're under 60" from U-joint eye to eye and mine measures exactly 58". I wounder is the margin starts at 60" or if its plus or minus 2"? My theory on this is; less moving parts and cheaper on joints with only two. I don't want to make a barber shop pole out of my drive shaft if this won't work. Anyone try this yet?



Also, 1350 yokes seem a bit smaller than the stock AAM yokes, especially when you look at the U-joint cap size difference. If thats what GV suggest then I guess thats good enough

Thanks

 

[HCanales]

I did talk to GV and they sent me a carrier relocation bracket. However, the local drive-line guys told me they would prefer a one piece shaft for reliability if measurments permit. So I went on ahead and chose the single shaft, I feel a lot more confident after talking to the experts. Thanks Ron I'll let you folks know how it goes.

 

[chris7694]

How much did the one piece driveshaft set you back? The '08 longbeds/megas have a one piece aluminum shaft. It's only $260 from the dealer. There is a guy on DTR swapping one into his '06 QC LB. 1 piece drive line???!! - Dodge Diesel - Diesel Truck Resource Forums

 

[DerekW]

I agree, I have 3:54's with the Gear Vendor and it has never seen 23 mpg!!!

I bought mine for the extra gears, not economy.

why not try propane. you get more HP. cleaner burning engine. and more MPG. not only that its cheaper than gear vendors. all they sell you is the stuff to give you the extra OD. you still need a retubed and balanced driveshaft up front also shortened and balanced shaft out back. plus your consumables and potentially taking it to a shop for install since alot of people fear going into a t-case (they are really simple got one gonna be here in 20 minutes to yank rebuild install in my driveway). if your looking for 2 mpg that your prolly wont get, theres alot better alternatives.

 

[chris7694]

I guess if propane could split gears he'd be sold on it? GV is not a magic bullet for improved economy. It does nothing to make that better. Whatever your truck gets now at 65mph is about what it will maintain to 84 mph or so with GV. If you're like me and drive a lot of empty interstate miles at 80+ mph it is good. Or frequent towing up steep grades. . If not, well... Even though it's good for me the fuel savings would take hundreds of thousands of miles to justify. . However engine longevity, due to reduced wear at lower rpms, should theoretically mean my engine is gonna last longer than typical if maintained properly not to mention the extra choices for keeping optimum rpms towing up grades. . So if the truck you have now is the same one you figured on having 30 years from now there is some benefit. .

 

[MMeier]

Just remember, the GV unit is not recommended for over 30,000# GVW.

 

[HCanales]

We have pros and cons on anything my friends. I'm happy with my GV just got it put in Fri, man... that's instant gratification. I gained about 3. 4 miles to the gallon and it feels like I'm idling down the road. I will never own a truck with 4. 10s and not have a GV. The drive shaft cost $118. 54 to get a 57" one piece shaft made. If I tow anything over 30,000 pounds I'm using the wrong vehicle for the job.

Again guys thanks for your support in my GV I'm greatful for this site and all your inputs Good or bad, thanks guys HCanales.

 

[hdtrukn]

Is that hand calculated or overhead ?

Is there a difference in MPH as with tire size change ?

Just thinking out loud.

I really need to go that route, run 80+mph all the time. Thats 2500-2600rpm.

She's hummin.

 

[BrianJ]

We have pros and cons on anything my friends. I'm happy with my GV just got it put in Fri, man... that's instant gratification. I gained about 3. 4 miles to the gallon and it feels like I'm idling down the road. I will never own a truck with 4. 10s and not have a GV. The drive shaft cost $118. 54 to get a 57" one piece shaft made. If I tow anything over 30,000 pounds I'm using the wrong vehicle for the job.

Again guys thanks for your support in my GV I'm greatful for this site and all your inputs Good or bad, thanks guys HCanales.

Hopefully the gain you see holds out for you, but keep in mind one tank does not make a sufficient sample size. Anyone I know that has added a GV saw better increases at first, then settled in at an average of appx 1mpg better overall (perhaps a little more in perfect conditions, i. e. empty on highway with favorable winds, also no different in some conditions). Why did they get better at first? The placibo affect, as they DROVE for better mileage. Once the dust settled and the "newness" ran off and they were driving like they usually do the mileage came back down to the average I mentioned.



Cummins themselves (in their mileage whitepaper) indicate the largest factor to mileage is the driver, with the most efficient as much as 30% better than the least efficient.

 

[BGlidewell]

Hopefully the gain you see holds out for you, but keep in mind one tank does not make a sufficient sample size. Anyone I know that has added a GV saw better increases at first, then settled in at an average of appx 1mpg better overall (perhaps a little more in perfect conditions, i. e. empty on highway with favorable winds, also no different in some conditions). Why did they get better at first? The placibo affect, as they DROVE for better mileage. Once the dust settled and the "newness" ran off and they were driving like they usually do the mileage came back down to the average I mentioned.

Cummins themselves (in their mileage whitepaper) indicate the largest factor to mileage is the driver, with the most efficient as much as 30% better than the least efficient.

This is why I did not opt for one although I was tempted. The operation of the GV is too manual for me as well since I'm driving mostly city now. If it was integrated into the shift sequence, that would cinch it for me though...

 

[ronman]

... I really need to go that route, run 80+mph all the time. Thats 2500-2600rpm.

She's hummin.

I can attest, at highway speeds, the GV will make the truck a lot quieter and the RPM drop will make the engine 'happier'. I'm on my second CDT with a GVOD and will not own one without it!

 

[chris7694]

Is that hand calculated or overhead ?

Is there a difference in MPH as with tire size change ?

Just thinking out loud.

I really need to go that route, run 80+mph all the time. Thats 2500-2600rpm.

She's hummin.

Doesn't change odometer mph. The only thing ever changing that would be larger/smaller tire size. I never saw a mpg increase with my unit. However it did maintain the same mileage I was getting stock at 63mph/2000rpms all the way up to the new 2000rpm speed of 84mph. I like running 80+ on the big roads too and I'm out there on them quiet a lot. Before gear vendors my interstate habits routinely sucked my mileage down to 15mpg but now I'm always good for just a shade under 19.

 

[tfiler]

Jumping into this discussion late, but I have a GV on my 1998. 5 and it has 3. 55 gears. I would not buy another GV. I really use it to climb hills and only get 3rd high. It can't be used in 1st or 2nd (by the time I reach 20 MPH, I just shift to 3rd). The difference between 4 high and 5th is only about 100 rpm and I loose more than that shifting the GV. I rarely shift to 5th high because I don't go over 75 MPH towing a trailer.



From day one of getting the GV installed I have had problems. I actually need to post a message here about another problem I am having.

 

[hdtrukn]

Guesss I am Confused ?

Do you have overdrive or underdrive ?

If overdrive why would you do that with 3. 55's ? I run 4. 10's and really like them but would love to be able to shift into second overdrive at 75mph and set the cruise at 80mph turning 2000rpm instead of the 2500 I turn now.

dont know if I would use it for anything else, really like the pulling power of 4. 10's.

 

[tfiler]

In my truck, the GearVendor is an overdrive. I have a friend with 4. 10 gears and he loves his GearVendor. Using his experience (and it sounds like your experience) 4. 10 and the GearVendor would make a perfect combination.

 

[hsmith]

Gear Vendor only makes the overdrive. I like mine when towing being able to "split" gears. Mine has 3:54's and I think anyone with 4:10's would really appreciate it more.

 

[DerekW]

being able to use OD and split gears would be nice but they dont seem to have plans to move the gv unit to between the t-case and the trans. thats why i never looked any further. I used to get all sorts of unwanted attention during some situations beyond my control until i started using 4wd on the street in certain situations only. roads aint engineered so well around here. making u-turns in a 55 mph zone with people doing 60-70mph dont seem to work well with lots of torque. *insert burn-out smiley*. i also wanted the GV for offroad useage to get that "right" gear as i do lots of mileage where i need 4wd and fuel consumption is at a minimum at 1800 to 2000 rpms on this truck