Gear Vendors Overdrives

[BrentN]

Hey all:
Just wanted to find out who all uses a gear vendors overdrive. Want to find out if there are any issues I should be concerned with if I were to go looking for one (and who has the best deals). Obviously if anyone has one for sale I would be interested.

Thanks,

[HowieE]

I had one on my 87 for 4 or 5 years. It worked fine and never had any service problems with the unit itself. When I installed it I had a problem witht the control box but it was replaced without question.
With what you have and what you are pulling why do you think you need one? The old 6.2 needed on because I had to pull in 3rd with a 700r4 so the gear Vendor gave me a 3rd over for towing. With a 4.10 rear the only need you should have is for a OD over for highway fuel milage when not towing.

[Spindrift]

For heavy towing, is the Gear Vendors unity meant to replace, or supplement a BD Torq Loc unit? Reason I'm asking is because I came across this interesting piece of equipment and now I'm wondering if the CompuShift is the way to go...period.

http://www.compushift.com/compushift.htm

[rjschoolcraft]

The Gear Vendors unit is an actual auxilliary transmission that mounts behind your factory transmission. It gives you either overdrive or underdrive, depending upon the installation.

The Compushift that you linked to looks interesting. It is simply an electronic control module to override the factory control... or maybe to allow use of an electronic transmission in an older vehicle. The one draw back that I saw on their website... it does not appear to allow lock-up of the converter clutch in second gear.

[Spindrift]

RJ,

I had called Compushift a few weeks ago and I recall that he said there is "infinite variability" (maybe a little exhaggeration on his part), including lock-up in second gear. Given the higher cost of the Gear Vendors unit, I'm thinkin' this isn't a bad option to investigate further. Don't know what the BD unit sells for, but the Compushift has been tested on the newer 4L80Es with no problems, according to the seller.

[LanduytG]

I have had the GV in my 95 for about the last 75K miles and works great. I use mine all the time even when towing. Depending on the needs at the time I might run 3rd over which is a bit better gear ration than OD. I also towing in double over drive as long as I can run at least 70mph or better. They say not to run double over but with 4:10's if you look at the chart its no worse than running OD with 3:45 gears. When pulling a car hauling in OD I would get 11-12 mpg. Go to double OD and went to 14-14.5 mpg. Plus another big thing doing this is coolant temp drops and EGT's go way down, not to mention the noise reduction. I love mine and when the son gets done with the truck I will take it out and use in something else. As far as install goes it was very easy, but I do recommend you get the best shop for the drive shaft work. I had to pull mine 2 times for it to be balanced correctly. The 3 time I went to the shop that I should have used in the first place.

Greg

[Dvldog 8793]

Howdy
I have had a GV for about 100k miles in my truck. All I can say is that it is great. My truck gets very mixed loads from family highway trip miles to pulling gooseneck full of steel. My truck has 4.10s and it is great for pulling however they suck for highway use. With the Gearvendor you get the best of both worlds. I can tell you for fact that trans temps are about 20* lower by pulling in 3rd OD, also as stated above the EGT's oil temp and engine temps tend to be lower. I'm pretty sure that the GV has paid for itself in fuel and acceseory(less rpm) life. The only complaint that I would have is the cost of the recomended oil. Factory service has been great. I needed new drain plug/fill plugs and they fed-exed them now charge.
The torque rating of a GV is greater than that of the 4l80e trans. They are definently HEAVY DUTY!
Hope this helps!
L8r
Conley Janssen

[Dvldog 8793]

Speaking of Gearvendor oil.... Does anyone run something other than the GM or Mopar synthetic?
I'm Looking for a cheaper way......

[BrentN]

I would definately be looking at the overdrive feature of the GV unit. With my 4:10 rear end, I am running some decent rpms.

Primarily, the OD unit would be used when unladen. However, given the torque of this beast, I am thinking that OD while towing especially on flat ground is feasible.

I would have driveline shop do the shaft. The one question I have is does the unit go to a 1:1 mode so that I can retain standard ratios in addition to the overdrive ratios?

Ah, and to find one without breaking the bank.

Thanks,

[Dvldog 8793]

Howdy
The GV is pretty much an overdrive for each gear. If you wanted to use it that way. If you turn it off then you retain all of your standard gearing. Also you HAVE to turn it off for 4x4 use. I think the reduction is something like .33 but I'm not sure. I know that with my tires and the GV my final drive is about the same as if I had 3.40 rear gears. If you call the tech line they will send you out a package with prices :eek:
Ain't cheap.

[DA BIG ONE]

Originally posted by BrentN:
Hey all:
Just wanted to find out who all uses a gear vendors overdrive. Want to find out if there are any issues I should be concerned with if I were to go looking for one (and who has the best deals). Obviously if anyone has one for sale I would be interested.

Thanks, I see you have a 1999 BURB, if it is 4wd then it should have a NP246 t-case/auto 4wd, if so, then gear vendors will not have an od/ud unit for it "even though their site lists an od/ud for the NP246".

Problem is the 3 speed sensors for auto 4wd on the NP246 t-case w/gear vendors engaged, the abs system, and the drive shafts turning at different speeds.

I went to 3.42:1 from 4.10:1 on my 99 burb and hardly notice the change around town because of all the torque the motor has. Surely, I reduced the amount of weight I can pull this way but now engine runs at peak torque at 70mph, and the much better mpg's is a plus.

Off road the gear set is not an issue because of low ratio of the NP246.

[LanduytG]

Dvldog 8793
I use the Amsoil Series 2000 75W-90 in my GV.


As for changing out the 4:10's, never will do that. Main reason is when pulling out of a drive onto a road with a steep grade I can split the gears with the GV and gain road speed fast. By changing to a higher gear I would not have that advantage. But if I was not towing much of a load I think it would work very well and most likely be more efficient.

Greg

[ANXIOUS-SUBMAN]

BrentN,
Your burb might have the NP246 only if it has AutoTrac which was optional on our trucks. (operated by buttons on the dash) Otherwise it would have the NP241C like mine. (stick on the floor)

No, I don't have a GV but would like to have one too.

[moondoggie]

Good Day!

As you can see from my profile, I have a GV on my 95 pickup. I only got it to improve mpg. It has done that (What's your fuel mileage with a load? (http://forum.thedieselpage.com/cgi-bin/ultimatebb.cgi?ubb=get_topic&f=1&t=004439#000014) (Click in colored text.)) for me. It will take awhile to pay for itself, but I really don't care. The truck also gets REAL QUIET when it's engaged. If Scottie beamed you into my pickup when I'm going 65 mph or so, you'd never be able to guess it's a diesel.

You can use any gear lube that is NOT labelled "extreme pressure." I've used both synthetic & non-synthetic, but will now be using synthetic exclusively for its longer drain intervals.

It might be important to understand how the GV works. There's a pump on the input shaft, so it can't engage until a minimum input shaft rpm is reached. The manual says 18 mph minimum, but of course this would vary depending on rear end ratio - I think 18 mph is fast enough for even the tallest gears.

It has an auto mode which engages at ≈ 48 mph. I never use it - it shakes the whole truck. I use the foot switch to engage/disengage the unit at the time & speed that I want. I do this in auto mode so it will disengage at ≈ 25 mph on slow-down, in case I forget to do it with the foot switch. Done this way, you'd be hard pressed to know it was shifting in or out, it's so smooth.

lessings!

Brian Johnson, #5044

[Steve O.]

How was the install on the GV unit?

What did you guys pay to get the shortened driveshaft?

Steve

[Dvldog 8793]

Howdy
For the average shade tree mechanic the install would not be hard. The instructions were not the best but the tech line was very good and faxed me updates while I waited. The most difficult part of the install for my truck was the wiring. You pretty much have to open up the dash. All in all the install took me about 2 days. I had drive shaft shortened in advance so I wouldn't be down whil I was waiting. To shorten the drive shaft was $125.00 with computer balancing and new u-joints.
L8r
Conley

[gymcarm]

So you can't keep it engaged from zero ground speed. Is there a different brand that WILL allow overdrive from zero?

My intent is to keep it engaged until I have to use the 4x4 and then I would like it to automagically switch to direct drive.

This is the wife's vehicle and I need it to be as seamless as possible.

Updating the signature to reflect the 4.10 gears...

[Dvldog 8793]

Howdy
The Gearvendor control box automatically engages at 48mph and disengages at 22mph. Also it will not allow itself to engage with the 4x4 on. The only problem with the "Autodrive" system is that when it engages you will know it. It really bangs into gear, the first time it engaged I stopped the truck and called Gearvendor on the cell phone. They told that it was normal and would not hurt a thing. 100,000 miles later and it still hurts my head! I know how to operate it so that you can never even feel it engage but depending on your wife that may not be an option.
Check out GMCTD's truck. or check with US overdrives they also make a aux overdrive.
www.usgear.com (http://www.usgear.com)
Hope this helps!
L8r
Conley

[ANXIOUS-SUBMAN]

I recently purchased a Gear Vendor unit from another member on the TDP Classified Ad Forum. It will be awhile before I get to do the installation. After eyeballing things under the truck I called GV about what looked like an interferrence problem with the cross member behind the transfer case. They tell me that I will have to cut out a section of the cross member to make room for the GV. They have a reinforcement bracket available that bolts to the bottom and along the length of the crossmember after it's cut out. I was wondering if anyone here has had to do the same thing and has any pictures to share of what the cross member looks like with the bracket installed.
Thanks

[ 03-27-2005, 05:32 PM: Message edited by: ANXIOUS SUBMAN ]

[Craig M]

gymcarn

You can leave it on auto from "zero" but it will only actually engage in high gear. It does not automatically give you OD in each of the gears. To get OD in each gear one has to use the manual switch. Unless one is towing a heavy load the OD in each gear is not usually necessary.