Finally got to experience the Gear Vendors O/D unit - long post - The 1947 - Present Chevrolet & GMC Truck Message Board Network

clapage6 · 11-20-2013, 03:33 PM

I bought my 83k30 cc Dually in feb. of 2013.

It's used only to haul my desert toys out to the dunes and move loads to the dump etc.

When I first bought the truck I bought it under the impression the the gear vendor o/d unit dide NOT function. Although installed it would not stay engaged in Over drive. it would "hunt", keep kicking in/out etc...

Well i drove the truck like that with no overdrive even testing out and hauling a 12k dry weight 5th wheel toy hauler out to the dunes (not sure what total weight is loaded. would assume roughly 14k) It was NOT pleasant through the grades but wasn't terrible either with 4.56's. with speed limit of 55 anyways. I was roughly 3400 rpm to maintain 55mph in 2nd gear (which i just wouldn't) so up the grade i'd cruise probably 45mph to keep rpm's down.) (temps all stayed fine regardless of rpm)

Well, when i got back, i decided I'd do my best to trouble shoot and/or replace the GV and see how it towed. I emailed GV first with little luck. When I finally got a response it wasn't a helpful one but one pushing me to just exchange mine for a rebuilt unit at I think $650 or some number near there. Well I called them up after that and trouble shoot some more. This was much more productive... testing everything from the solenoid actuation to pump pressure and even tried a new solenoid to no avail. new fluids etc. Again it was recommended I exchange my unit for a rebuilt on and cough up the $650. Although I was now slightly more convinced.. I decided to troubleshoot one last time on my own.

The first and only test i did was hook my solenoid up to 12v via a toggle switch with the other solenoid pin to ground of course. And the gear vendor worked perfect and stayed in overdrive without issues. Imagine that..... never once was it suggested to bypass my electronics. Now i don't know if that had to do with my explanation of the problems I was experiencing or what. but regardless I wasn't super impressed. But the fact My unit worked mad me happy enough to forget about it....and just run it off the toggle. Since I don't use it but on the highway anyways. (i won't forget to turn it off)

The game changer:

The truck tows AMAZINGLY with this set up now. 454 out of an RV/th400 with shift kit / 4.56's/ gear vendor. It loves 2nd over towing that 14k up through the mountains NO PROBLEM... I'm cruising 55-60 without the engine screaming. And same in 3rd over on the flats. When this unit is working it seriously made an amazing improvement in drive-ability. I couldn't be happier.. that might change if i forget to turn off the overdrive before stopping, during power braking, or going into reverse..... but I'll be trying real hard not to forget.

bnoon · 11-20-2013, 05:59 PM

Dang! I need to get me one of those OD's!!!

LONGHAIR · 11-20-2013, 08:32 PM

Quote:

Originally Posted by clapage6

I couldn't be happier.. that might change if i forget to turn off the overdrive before stopping, during power braking, or going into reverse..... but I'll be trying real hard not to forget.

Why? What would happen?

clapage6 · 11-20-2013, 08:56 PM

Quote:

Originally Posted by LONGHAIR

Why? What would happen?

well, i do know below 20 miles per hour the gear vendor pump does not produce enough pressure to hold the clutches. other than that i just know any of those actions is NOT good for your gear vendor and can possible destroy it. The electronics they produce are designed specifically to disengage the o/d anytime you're driving in a manner the gv is not meant to operate. And since i bypassed all that at the moment.

willett · 11-20-2013, 08:57 PM

The engine will fight the brakes I'm guessing, and it will be a dog off the line I it's engaged at a stop light.

SCOTI · 11-20-2013, 09:15 PM

Quote:

Originally Posted by willett

The engine will fight the brakes I'm guessing, and it will be a dog off the line I it's engaged at a stop light.

G/V units are under/over drives. I would think engaging it from a stop would/should not be an issue because that would be required to under-drive.

Perhaps the toggle strictly engaging OD is the difference here?? I do know I read where RideTech destroyed their unit that was in the '48hr Camaro' by leaving it engaged when moving to reverse (or something goofy like that).

clapage6 · 11-20-2013, 11:35 PM

Quote:

Originally Posted by SCOTI

G/V units are under/over drives. I would think engaging it from a stop would/should not be an issue because that would be required to under-drive.

Perhaps the toggle strictly engaging OD is the difference here?? I do know I read where RideTech destroyed their unit that was in the '48hr Camaro' by leaving it engaged when moving to reverse (or something goofy like that).

Yep I know leaving it engaged in reverse, you will definitely destroy a gv real fast. Taking off from a atop wont do much since the pump cant hold the clutches until 20mph anyways. I also know by bypass the electronics I'm still doing exactly what they would be doing. Just at a manual interval controlled by said switch. I'm not sure if it's called over/under because you have an in between gear so 1st over is technically 2nd under? Or if its because they may offer it in an under drive variant? I just think of mine as an o/d unit. Easier to wrap my head around.

SCOTI · 11-21-2013, 01:38 AM

True.... It would be 1st, 1st od, 2nd, 2nd od, drive, & over-drive.

Alex V. · 11-21-2013, 03:03 AM

Would it be all that hard to wire something up to the back-up light circuit to override the toggle switch when the BU light circuit comes on? Just for safety's sake?

clapage6 · 11-21-2013, 03:47 AM

Quote:

Originally Posted by Alex V.

Would it be all that hard to wire something up to the back-up light circuit to override the toggle switch when the BU light circuit comes on? Just for safety's sake?

wouldn't be hard at all really, I do plan on replacing the GV electronics though eventually and I never felt the need to use the o/d around town. Only on the highway/towing for me.

Tucson38 · 11-21-2013, 11:07 AM

If I'm reading this right, the OD unit has a lot of severe limitations on it's use. Pretty surprising. I once had a Warn all-range overdrive in a 66 CJ5 that I could engage/disengage at will with no repercussions. I was pretty interested in the Gear Vendor's unit for my '85 GMC but now I have serious doubts.

clapage6 · 11-21-2013, 12:46 PM

Quote:

Originally Posted by Tucson38

If I'm reading this right, the OD unit has a lot of severe limitations on it's use. Pretty surprising. I once had a Warn all-range overdrive in a 66 CJ5 that I could engage/disengage at will with no repercussions. I was pretty interested in the Gear Vendor's unit for my '85 GMC but now I have serious doubts.

Yeah totally....If I had the cashflow, I'd prefer a newer factory o/d trans. I personally don't believe in the 700r4 for what I tow etc. but I'm sure they can be built for such.... so my next options get pricey. With the GV electronics...their unit engages at will and at the correct times. I know the electronics I have are 2 generations old. So i don't know the reliability of the newer stuff. And I'd buy a factory o/d trans before a Brand new GV unit. that's for sure. This one was technically free in my eyes. Either way even if I had it on with the electronics all the time.. I'd always be worried about their electronics not controlling it just right and leaving me stranded or something... atleast now I can just blame myself if i forget to flip the switch

monte0185 · 11-21-2013, 02:06 PM

Ive only used mine on the drive home with the truck so far but It definatley helps on gas mileage Ill say that.

slimneverdies · 01-01-2015, 10:26 PM

So from what I'm reading you have to still manually engage the trans for different driving witht the gearvendors? It seems like it's just better to buy a 4l80e and controller so you could just drive and not worry about the unit...

monte0185 · 01-01-2015, 10:36 PM

Quote:

Originally Posted by slimneverdies

So from what I'm reading you have to still manually engage the trans for different driving witht the gearvendors? It seems like it's just better to buy a 4l80e and controller so you could just drive and not worry about the unit...

the gear vendors has a controller and a manual switch for the in between gears.

clapage6 · 01-01-2015, 11:07 PM

Quote:

Originally Posted by slimneverdies

So from what I'm reading you have to still manually engage the trans for different driving witht the gearvendors? It seems like it's just better to buy a 4l80e and controller so you could just drive and not worry about the unit...

when you buy the kit it does have it's "automatic mode" and a manual mode which you can shift on your own. I believe both modes has the 4x4 lockout+low mph kick off, and reverse lockout. Just with the manual mode you get to decide when it shifts which I prefer, and although a 4l80 is nice the hassle of the install is far less with a GV

monte0185 · 01-01-2015, 11:34 PM

Quote:

Originally Posted by clapage6

when you buy the kit it does have it's "automatic mode" and a manual mode which you can shift on your own. I believe both modes has the 4x4 lockout+low mph kick off, and reverse lockout. Just with the manual mode you get to decide when it shifts which I prefer, and although a 4l80 is nice the hassle of the install is far less with a GV

My plan is to add a 4l80 and bolt my gv to it. That way I have an over/overdrive for the highway non towing trips.

**Corts60** · 01-02-2015, 12:37 AM

I run my gear venders manually by a second dimmer foot switch under the brake pedal. It works great behind my T400. My favorite uphill towing gear combo is 2nd gear with the GV engaged or 2nd over. Perfect range for my little diesel. The GV is a very strong unit, but it definitely cannot handle reverse while engaged. As far as I know, that is it's only weakness. And since I controlled my GV manually I had to kick it out when coming to a stop, if I forgot it would shift out of first gear and immediately engage the GV which would make the truck dog. If that happens, you just kick the GV back out again.

Also, word of advice for manually operating the GV: when disengaging the unit, make sure you have a light load on the engine i.e.: your foot just lightly pressed on the gas pedal. If you kick it out with your foot off of the gas while you're decelerating, the GV slams really hard and could (and will) break u-joints.

My GV unit has over 250,000 miles on it. I just now sent it back for overhaul because it finally starting slipping under heavy load.

tucsonjwt · 01-02-2015, 12:44 AM

My 83 454/SM 465 granny came with a GV when I bought it. Here is the only way it works in my truck:

I have a red engagement button below the shift knob (like a 2 speed axle in a big truck) connected to a cable which engages/disengages the GV unit. There is also an electronic box on the kick panel but I don't know what it does in a manual transmission unit because you must control the GV with that red button(described as an Eaton Locker by the GV rep I talked with.)

Start out with the GV disengaged in 2nd gear (granny low 1st is never used), shift into 3rd gear, depress clutch and engage GV with red button when shifting between 3rd and 4th. If you don't use the clutch and engage or disengage only in neutral the GV unit will "slap" into engagement and make an unpleasant clunk. The GV rep stated that this indicates you are improperly engaging/disengaging the GV unit which will damage it.

The vehicle must be traveling at at least 20 mph or the GV won't engage (maybe that is what the electronics is for - it is connected to the VSS in the speedo cable.) So, I actually only get one more gear out of it - 4th is now 5th over, so a kind of overdrive. I think with a manual transmission with 5 useable gears you could use the GV in more than one gear.

I found the GV tech rep to be very helpful, but I did have to call twice to get the information I wanted. They don't like to talk to do it yourselfers - they have designated shops they want you to go to. I had a designated shop round out the allen head drain bolt when refilling it with proper GM posi fluid, so I talked the GV rep into selling me a new bolt and sump gasket.

I might take them up on that $650 rebuild offer - sounds fair to me for a $3k+ unit.

GV advertises 20% better fuel economy, and I went from 9 to 11 mpg. They state that automatic transmissions with lock up torque converters will not get better fuel economy, but will get better towing performance.

slimneverdies · 01-02-2015, 12:06 PM

It just seems to me after reading all this info that the GV is not as automatic as I thought. You have to manually disengage it for the reverse mode and also disengage the overdrive if I was driving in stop and go traffic under 20 mph. All the extra coin for th GV I was expecting it to at least perform like a modern transmission and being able to just jump in and shift the truck like a new vehicle is what I'm really after but just with overdrive...

monte0185 · 01-02-2015, 05:26 PM

Quote:

Originally Posted by slimneverdies

It just seems to me after reading all this info that the GV is not as automatic as I thought. You have to manually disengage it for the reverse mode and also disengage the overdrive if I was driving in stop and go traffic under 20 mph. All the extra coin for th GV I was expecting it to at least perform like a modern transmission and being able to just jump in and shift the truck like a new vehicle is what I'm really after but just with overdrive...

That is exactly what i do with mine and it works great. I like having the option to kick it in when pulling though at lower speeds. If you never plan to pull anything then just get you a OD tranny.

tucsonjwt · 01-02-2015, 09:43 PM

In my case, with a manual transmission your are shifting all of the time anyway, especially in city driving. It is no effort to pull up or push down the red button under the shift knob when moving into 4th gear or when coming to a stop. Unless you tow a heavy load a lot, a GV is not worth the thousands in cost. Mine came "for free" when I bought the old truck. The previous owner used the truck to haul a truck camper and tow a trailer, so it made sense in that case. Towing/hauling is where they work best.

monte0185 · 01-02-2015, 09:46 PM

Mine came with my truck as well but I haul crap with mine all the time and wife wants a big camper so I'm swapping a 4l80 and 8.1l into mine this summer. Well the 8.1l to start with.

77 Big 10 · 08-16-2015, 05:03 PM

I use mine in the manual setting, with a dimmer like switch 12" below the factory dimmer switch. It keeps my truck in its power band, no lugging, so I use less fuel. It is also great for drag racing, once I got used to it, again it keeps the engine in its power band.

11-20-2013, 03:33 PM	#1
clapage6 Registered User Join Date: Aug 2013 Location: San Diego Posts: 111	Finally got to experience the Gear Vendors O/D unit - long post I bought my 83k30 cc Dually in feb. of 2013. It's used only to haul my desert toys out to the dunes and move loads to the dump etc. When I first bought the truck I bought it under the impression the the gear vendor o/d unit dide NOT function. Although installed it would not stay engaged in Over drive. it would "hunt", keep kicking in/out etc... Well i drove the truck like that with no overdrive even testing out and hauling a 12k dry weight 5th wheel toy hauler out to the dunes (not sure what total weight is loaded. would assume roughly 14k) It was NOT pleasant through the grades but wasn't terrible either with 4.56's. with speed limit of 55 anyways. I was roughly 3400 rpm to maintain 55mph in 2nd gear (which i just wouldn't) so up the grade i'd cruise probably 45mph to keep rpm's down.) (temps all stayed fine regardless of rpm) Well, when i got back, i decided I'd do my best to trouble shoot and/or replace the GV and see how it towed. I emailed GV first with little luck. When I finally got a response it wasn't a helpful one but one pushing me to just exchange mine for a rebuilt unit at I think $650 or some number near there. Well I called them up after that and trouble shoot some more. This was much more productive... testing everything from the solenoid actuation to pump pressure and even tried a new solenoid to no avail. new fluids etc. Again it was recommended I exchange my unit for a rebuilt on and cough up the $650. Although I was now slightly more convinced.. I decided to troubleshoot one last time on my own. The first and only test i did was hook my solenoid up to 12v via a toggle switch with the other solenoid pin to ground of course. And the gear vendor worked perfect and stayed in overdrive without issues. Imagine that..... never once was it suggested to bypass my electronics. Now i don't know if that had to do with my explanation of the problems I was experiencing or what. but regardless I wasn't super impressed. But the fact My unit worked mad me happy enough to forget about it....and just run it off the toggle. Since I don't use it but on the highway anyways. (i won't forget to turn it off) The game changer: The truck tows AMAZINGLY with this set up now. 454 out of an RV/th400 with shift kit / 4.56's/ gear vendor. It loves 2nd over towing that 14k up through the mountains NO PROBLEM... I'm cruising 55-60 without the engine screaming. And same in 3rd over on the flats. When this unit is working it seriously made an amazing improvement in drive-ability. I couldn't be happier.. that might change if i forget to turn off the overdrive before stopping, during power braking, or going into reverse..... but I'll be trying real hard not to forget.

11-20-2013, 05:59 PM	#2
bnoon Registered User Join Date: Jul 2012 Location: Des Moines IA Posts: 1,250	Re: Finally got to experience the Gear Vendors O/D unit - long post Dang! I need to get me one of those OD's!!! __________________ - 1981 Sierra 454, NV4500 swap - 2006 Z06, 25k miles - 1973 Nova - Project CarNova Virus on Youtube

11-20-2013, 08:57 PM	#5
willett Another Day, Another Dollar Join Date: Nov 2008 Location: North Vancouver, BC Posts: 1,316	Re: Finally got to experience the Gear Vendors O/D unit - long post The engine will fight the brakes I'm guessing, and it will be a dog off the line I it's engaged at a stop light. __________________ -78 K20 Cheyenne 454 long box, 4" lift, 35" MT's, '84 cab, '80 box "its hip to be square"

11-21-2013, 01:38 AM	#8
SCOTI Registered User Join Date: Apr 2001 Location: DALLAS,TX Posts: 21,939	Re: Finally got to experience the Gear Vendors O/D unit - long post True.... It would be 1st, 1st od, 2nd, 2nd od, drive, & over-drive. __________________ 67SWB-B.B.RetroRod 64SWB-Recycle 89CCDually-Driver/Tow Truck 99CCSWB Driver All Fleetsides @rattlecankustoms in IG Building a small, high rpm engine with the perfect bore, stroke and rod ratio is very impressive. It's like a highly skilled Morrocan sword fighter with a Damascus Steel Scimitar..... *Cubic inches is like Indiana Jones with a cheap pistol.*

11-21-2013, 03:03 AM	#9
Alex V. Registered User Join Date: Mar 2013 Location: Campbellsville, KY Posts: 888	Re: Finally got to experience the Gear Vendors O/D unit - long post Would it be all that hard to wire something up to the back-up light circuit to override the toggle switch when the BU light circuit comes on? Just for safety's sake? __________________ Alex V. ------ 1967 C10 Suburban, 350/NP435, Green/Green, PS, PB, HD cooling, charging, shocks, and springs. 1985 GMC C3500 SRW, Sierra Classic, 454/TH400, white/blue.

11-21-2013, 11:07 AM	#11
Tucson38 Registered User Join Date: Aug 2011 Location: Tucson Arizona Posts: 164	Re: Finally got to experience the Gear Vendors O/D unit - long post If I'm reading this right, the OD unit has a lot of severe limitations on it's use. Pretty surprising. I once had a Warn all-range overdrive in a 66 CJ5 that I could engage/disengage at will with no repercussions. I was pretty interested in the Gear Vendor's unit for my '85 GMC but now I have serious doubts.

11-21-2013, 02:06 PM	#13
monte0185 Registered User Join Date: Oct 2008 Location: Brighton, TN Posts: 1,267	Re: Finally got to experience the Gear Vendors O/D unit - long post Ive only used mine on the drive home with the truck so far but It definatley helps on gas mileage Ill say that. __________________ A computer once beat me at chess, but it was no match for me at kick boxing. Duct tape is like the force. It has a light side, a dark side, and it holds the world together.

01-01-2015, 10:26 PM	#14
slimneverdies Registered User Join Date: Apr 2006 Location: Miami now in Vegas Posts: 828	Re: Finally got to experience the Gear Vendors O/D unit - long post So from what I'm reading you have to still manually engage the trans for different driving witht the gearvendors? It seems like it's just better to buy a 4l80e and controller so you could just drive and not worry about the unit... __________________ Long live SLIM ------------------ At least try to buy American

01-02-2015, 12:37 AM	#18
Corts60 Just here to tinker Join Date: Jun 2008 Location: Holland, MI Posts: 3,689	Re: Finally got to experience the Gear Vendors O/D unit - long post I run my gear venders manually by a second dimmer foot switch under the brake pedal. It works great behind my T400. My favorite uphill towing gear combo is 2nd gear with the GV engaged or 2nd over. Perfect range for my little diesel. The GV is a very strong unit, but it definitely cannot handle reverse while engaged. As far as I know, that is it's only weakness. And since I controlled my GV manually I had to kick it out when coming to a stop, if I forgot it would shift out of first gear and immediately engage the GV which would make the truck dog. If that happens, you just kick the GV back out again. Also, word of advice for manually operating the GV: when disengaging the unit, make sure you have a light load on the engine i.e.: your foot just lightly pressed on the gas pedal. If you kick it out with your foot off of the gas while you're decelerating, the GV slams really hard and could (and will) break u-joints. My GV unit has over 250,000 miles on it. I just now sent it back for overhaul because it finally starting slipping under heavy load. __________________ 78 C10 SWB Diesel #1 (wrecked)http://67-72chevytrucks.com/vboard/s...1978+silverado 78 C10 SWB Diesel #2 (sold)http://67-72chevytrucks.com/vboard/s...d.php?t=650751 60 GMC Suburban (sold)http://67-72chevytrucks.com/vboard/s...d.php?t=445526 60 GMC 1000 (sold)http://67-72chevytrucks.com/vboard/s...d.php?t=298235 67 GMC 1500 (sold) http://67-72chevytrucks.com/vboard/s...d.php?t=803695 86 Suburban(summer unit) http://67-72chevytrucks.com/vboard/s...d.php?t=810697 88 Suburban 4x4(winter unit)https://67-72chevytrucks.com/vboard/...25#post8900725

01-02-2015, 12:44 AM	#19
tucsonjwt Registered User Join Date: Jul 2007 Location: Tucson, AZ Posts: 3,188	Re: Finally got to experience the Gear Vendors O/D unit - long post My 83 454/SM 465 granny came with a GV when I bought it. Here is the only way it works in my truck: I have a red engagement button below the shift knob (like a 2 speed axle in a big truck) connected to a cable which engages/disengages the GV unit. There is also an electronic box on the kick panel but I don't know what it does in a manual transmission unit because you must control the GV with that red button(described as an Eaton Locker by the GV rep I talked with.) Start out with the GV disengaged in 2nd gear (granny low 1st is never used), shift into 3rd gear, depress clutch and engage GV with red button when shifting between 3rd and 4th. If you don't use the clutch and engage or disengage only in neutral the GV unit will "slap" into engagement and make an unpleasant clunk. The GV rep stated that this indicates you are improperly engaging/disengaging the GV unit which will damage it. The vehicle must be traveling at at least 20 mph or the GV won't engage (maybe that is what the electronics is for - it is connected to the VSS in the speedo cable.) So, I actually only get one more gear out of it - 4th is now 5th over, so a kind of overdrive. I think with a manual transmission with 5 useable gears you could use the GV in more than one gear. I found the GV tech rep to be very helpful, but I did have to call twice to get the information I wanted. They don't like to talk to do it yourselfers - they have designated shops they want you to go to. I had a designated shop round out the allen head drain bolt when refilling it with proper GM posi fluid, so I talked the GV rep into selling me a new bolt and sump gasket. I might take them up on that $650 rebuild offer - sounds fair to me for a $3k+ unit. GV advertises 20% better fuel economy, and I went from 9 to 11 mpg. They state that automatic transmissions with lock up torque converters will not get better fuel economy, but will get better towing performance.

01-02-2015, 12:06 PM	#20
slimneverdies Registered User Join Date: Apr 2006 Location: Miami now in Vegas Posts: 828	Re: Finally got to experience the Gear Vendors O/D unit - long post It just seems to me after reading all this info that the GV is not as automatic as I thought. You have to manually disengage it for the reverse mode and also disengage the overdrive if I was driving in stop and go traffic under 20 mph. All the extra coin for th GV I was expecting it to at least perform like a modern transmission and being able to just jump in and shift the truck like a new vehicle is what I'm really after but just with overdrive... __________________ Long live SLIM ------------------ At least try to buy American

01-02-2015, 09:43 PM	#22
tucsonjwt Registered User Join Date: Jul 2007 Location: Tucson, AZ Posts: 3,188	Re: Finally got to experience the Gear Vendors O/D unit - long post In my case, with a manual transmission your are shifting all of the time anyway, especially in city driving. It is no effort to pull up or push down the red button under the shift knob when moving into 4th gear or when coming to a stop. Unless you tow a heavy load a lot, a GV is not worth the thousands in cost. Mine came "for free" when I bought the old truck. The previous owner used the truck to haul a truck camper and tow a trailer, so it made sense in that case. Towing/hauling is where they work best.

01-02-2015, 09:46 PM	#23
monte0185 Registered User Join Date: Oct 2008 Location: Brighton, TN Posts: 1,267	Re: Finally got to experience the Gear Vendors O/D unit - long post Mine came with my truck as well but I haul crap with mine all the time and wife wants a big camper so I'm swapping a 4l80 and 8.1l into mine this summer. Well the 8.1l to start with. __________________ A computer once beat me at chess, but it was no match for me at kick boxing. Duct tape is like the force. It has a light side, a dark side, and it holds the world together.

08-16-2015, 05:03 PM	#24
77 Big 10 Registered User Join Date: Jul 2015 Location: La Quinta, CA. Posts: 131	Re: Finally got to experience the Gear Vendors O/D unit - long post I use mine in the manual setting, with a dimmer like switch 12" below the factory dimmer switch. It keeps my truck in its power band, no lugging, so I use less fuel. It is also great for drag racing, once I got used to it, again it keeps the engine in its power band.



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