Share your experience good or bad with gear vendor Overdrive

[72Cheyenne454]

Originally Posted by seattle gmc

I have heard the gear vendors has a really "firm" shift. Is this true? Im really considering going with a gear vendors unit on my K2500 with manual trans. Also wondering if i will need and additional crossmember for it?

From my experience, GV units do have a firm shift. Not harsh, but definitely firm. Of course the firmness of the shift is also dependent upon the load going through it - light throttle, softer shift... hard/full throttle, firm shift.

No additional crossmember needed for your K2500 application. The unit simply bolts to the back of the T-Case. Here's a GV I installed on my K30 with a NP205.

Miles

[seattle gmc]

Originally Posted by 72Cheyenne454

From my experience, GV units do have a firm shift. Not harsh, but definitely firm. Of course the firmness of the shift is also dependent upon the load going through it - light throttle, softer shift... hard/full throttle, firm shift.

No additional crossmember needed for your K2500 application. The unit simply bolts to the back of the T-Case. Here's a GV I installed on my K30 with a NP205.

Miles

Thanks for the reply. I also saw somewhere that you cant use the gear vendors below certain speeds. Why? There are a lot of old dirt roads i go on (NOT in 4wd) where i think 2nd gear over would be a benifit. If that is a possibility. I recently moved back to southern Idaho and go out old mining roads all the time now.

[72Cheyenne454]

Originally Posted by seattle gmc

Thanks for the reply. I also saw somewhere that you cant use the gear vendors below certain speeds. Why? There are a lot of old dirt roads i go on (NOT in 4wd) where i think 2nd gear over would be a benifit. If that is a possibility. I recently moved back to southern Idaho and go out old mining roads all the time now.

If I remember correctly, a minimum speed (I believe it's 20mph) needs to be maintained in order to use the GV. I believe this is required for oil circulation. Anything under 20mph and you risk lack of lubrication.

[Sheepdip]

Here is my experience with my G/V OD unit. I've got one in my 49 GMC pickup it has always worked flawlessly mechanically and for the most part electrically about 15 years now.
After about 10 years or operation I replaced my HEI cap, rotor and plug wires....this thing instantly went nut's, it turned on, turned off and even came on in reverse (which is bad) all by it's lonesome self.

I called the G/Vendors tech and he only confirmed what I already knew is that I had R.F.I. interference. To be honest G/V offered no real solutions to solving the problem at hand.

Fast forward 3 or 4 months and I ran into a guy I know who happens to be a plant electrician who trouble shoots electrical problems at a local car show. I gave him the particulars and he told me to draw my 12 volts directly from the battery and switch it on with a relay from the ignition switch. He said take a lesson from car stereo installers here, a battery is a huge capacitor. I did as instructed and it has performed flawlessly since then.

[truckster]

Originally Posted by cleszkie

I installed one in my Blazer over a decade ago.

Dumb question time: Does the GV unit go between the trans and transfer case, or is it used only in 2wd? I have a TH350/NP205.

[Greg58]

Originally Posted by truckster

Dumb question time: Does the GV unit go between the trans and transfer case, or is it used only in 2wd? I have a TH350/NP205.

I would assume he can only use it in 2wd, the unit bolts to the back of the transfer case and the driveshaft slides into the OD unit.
I have a US Gear OD unit on an 87 suburban 454 t-400 2wd.
It came on the truck and works well, mine is manual only, takes the 4.11 ratio and converts it to 3.3 or so. You learn how to unload it a little when shifting up and down to avoid harsh shifts.

[cleszkie]

Originally Posted by truckster

Dumb question time: Does the GV unit go between the trans and transfer case, or is it used only in 2wd? I have a TH350/NP205.

The Gear Vendors OD mounts to the back of the NP205. Only overdrive in 2wd. No need for overdrive in 4wd.

[jeffahart]

Originally Posted by cleszkie

The Gear Vendors OD mounts to the back of the NP205. Only overdrive in 2wd. No need for overdrive in 4wd.

Are you running the sm465 with the long adapter? I've had my eye out for a GV for awhile. Since I had my issue with that long t-case adapter, It got me to thinking about another 40lbs hanging on the tail of the t-case. But it looks like you have big mile on the setup. I now have an aluminum adapter.


j

[cleszkie]

Originally Posted by jeffahart

Are you running the sm465 with the long adapter? I've had my eye out for a GV for awhile. Since I had my issue with that long t-case adapter, It got me to thinking about another 40lbs hanging on the tail of the t-case. But it looks like you have big mile on the setup. I now have an aluminum adapter.


j

I'm running a cast iron "figure 8" style adapter between my SM4665 and NP205. I guess you would call this the long adapter. As you know, the adapter "foot" bolts to the cross member to support the NP205. The NP205 also gets some support from the torque arm brackets that bolt between the passenger side of the t-case and the frame rail. I have had zero issues with my set up since installing the Gear Vendors on the back of the NP205 and I bounce the Blazer around a lot offroad, and tow heavy trailers. If you do get a Gear Vendors unit, you might think about swapping out the aluminum adapter for a cast iron one for some added strength. If the strength of any long style adapter concerns you, you can also convert to a short style adapter where the SM465 and NP205 are practically touching. But this would require some adjustments to your cross member (and more money).

[jeffahart]

Originally Posted by cleszkie

I'm running a cast iron "figure 8" style adapter between my SM4665 and NP205. I guess you would call this the long adapter. As you know, the adapter "foot" bolts to the cross member to support the NP205. The NP205 also gets some support from the torque arm brackets that bolt between the passenger side of the t-case and the frame rail. I have had zero issues with my set up since installing the Gear Vendors on the back of the NP205 and I bounce the Blazer around a lot offroad, and tow heavy trailers. If you do get a Gear Vendors unit, you might think about swapping out the aluminum adapter for a cast iron one for some added strength. If the strength of any long style adapter concerns you, you can also convert to a short style adapter where the SM465 and NP205 are practically touching. But this would require some adjustments to your cross member (and more money).

Thats good news. Couple other questions. So you are running the torque mount? I was going to leave mine off. I have poly mounts queued up for the engine and transfer mounts and have them for the torque mount. Are you running poly or rubber?

My failed adapter was the original, it had a hairline crack that leaked. Who knows, it probably could have held for years if I didn't chase down the leak. Advanced Adapter claims the aluminum is stronger, but I guess I will see when I finally dig up a GV. I paid a pretty penny for that adapter(It's going to work or die... damn it!) Thanks for answering.


j

[cleszkie]

Originally Posted by jeffahart

Thats good news. Couple other questions. So you are running the torque mount? I was going to leave mine off. I have poly mounts queued up for the engine and transfer mounts and have them for the torque mount. Are you running poly or rubber?

My failed adapter was the original, it had a hairline crack that leaked. Who knows, it probably could have held for years if I didn't chase down the leak. Advanced Adapter claims the aluminum is stronger, but I guess I will see when I finally dig up a GV. I paid a pretty penny for that adapter(It's going to work or die... damn it!) Thanks for answering.


j

Yes. Running the torque mount. Poly mounts everywhere. I should note that I also have a traction bar set up on the rear axle to eliminate leaf spring wrap under load. This puts even more stress on the mounts as the leaf springs no longer provide "slack" in the driveline when they used to give under load. But the truck now hooks up and pulls solid without the annoying jack-rabbiting when the clutch is released and the springs flex and unflex under load. But that is another story.

[mjervis]

Hi I was wondering if you could help me. I am putting a GV in my 72 C-20 and I am not sure where to run the power for the over drive box to on the fuse panel. It needs to go to a fuse that powers an accessory that comes on when key is on but not on crank. I am thinking wipers or radio, but not sure? I can't test it with light by cranking because driveshaft is off getting shortened. Just thought you might remember. Thanks Mike

[mjervis]

Hi I was wondering if you remember where you ran the power for your overdrive box to on your fuse box. I am just in the middle of putting a GV on my C-20. It is supposed to go to a fuse location that has power that comes on when when key is turned on but no power on crank. I am thinking wipers or radio but not sure. Thanks if you can help me. Mike

[toolboxchev]

I have a friend whom has one in a 4 speed long bed. Says he pulled it from a motor home.

Never an issue with it what so ever. Oh wait had I posted this before?

[HO455]

Originally Posted by mjervis

Hi I was wondering if you could help me. I am putting a GV in my 72 C-20 and I am not sure where to run the power for the over drive box to on the fuse panel. It needs to go to a fuse that powers an accessory that comes on when key is on but not on crank. I am thinking wipers or radio, but not sure? I can't test it with light by cranking because driveshaft is off getting shortened. Just thought you might remember. Thanks Mike

Both the wipers and the radio shut off when the ignition switch goes to the start position. I ran my power from the TH400 kickdown switch power wire.

[Sheepdip]

Originally Posted by mjervis

Hi I was wondering if you could help me. I am putting a GV in my 72 C-20 and I am not sure where to run the power for the over drive box to on the fuse panel. It needs to go to a fuse that powers an accessory that comes on when key is on but not on crank. I am thinking wipers or radio, but not sure? I can't test it with light by cranking because driveshaft is off getting shortened. Just thought you might remember. Thanks Mike

Do what you like or are comfortable with it's your truck....but here's how I ran mine: Pull your 12 volts lead directly from your battery with a 12 or 10 gauge wire to/thru a delay relay that powers up after a few preset seconds, that way you get 12 plus volts all the time anytime . Works flawlessly

G/V brains do not like low voltage period.

The 12 volts powers the brain which coordinates with the signal/speed generator off your speedometer to shoot power to the O/D engagement solenoid. The signal generator power/voltage increases with speed (and just using figures as an example) it stars at zero volts and goes to 16 volts, at or about 40 mph you will have the 16 volts to tell the brain you are going fast enough to generate the oil pressure required to safely engage the O/D.

When you start to slow down the speed generator voltage will decrease when you get to about 20 mph it will be roughly 8 volts, that low voltage signals the brain to cut the power to the solenoid and automatically disengages the O/D.

I run two of these units 1 auto and 1 manual trans with zero issues.

FYI: Delay relay is a... Hella 5 pin 12 volt P/N 5HE996.152-151

[HO455]

Originally Posted by Sheepdip

Do what you like or are comfortable with it's your truck....but here's how I ran mine: Pull your 12 volts lead directly from your battery with a 12 or 10 gauge wire to/thru a delay relay that powers up after a few preset seconds, that way you get 12 plus volts all the time anytime . Works flawlessly

G/V brains do not like low voltage period.

The 12 volts powers the brain which coordinates with the signal/speed generator off your speedometer to shoot power to the O/D engagement solenoid. The signal generator power/voltage increases with speed (and just using figures as an example) it stars at zero volts and goes to 16 volts, at or about 40 mph you will have the 16 volts to tell the brain you are going fast enough to generate the oil pressure required to safely engage the O/D.

When you start to slow down the speed generator voltage will decrease when you get to about 20 mph it will be roughly 8 volts, that low voltage signals the brain to cut the power to the solenoid and automatically disengages the O/D.

I run two of these units 1 auto and 1 manual trans with zero issues.

FYI: Delay relay is a... Hella 5 pin 12 volt P/N 5HE996.152-151

How did you get GV's to share the how they are using the signal generator? They were very closed mouthed about how it works when I talked to them. They wouldn't even confirm if they were using a hall effect sender or a pulse generator.

[72LB]

Does anyone have a 3:08 gear behind theirs? I've been thinking about putting a Gear Vendor behind my TH400 but thinking the gear is to high.

[68Gold/white]

Sooo, the overdriven ratio in the GV units is .78:1 ??? Is it the only ratio available???

[Sheepdip]

Originally Posted by HO455

How did you get GV's to share the how they are using the signal generator? They were very closed mouthed about how it works when I talked to them. They wouldn't even confirm if they were using a hall effect sender or a pulse generator.

You are very correct in G/V's tight lipped about anything to do with their products, which I think hampers them from selling more units.

The first major problem I had that I had which turned out to be radio frequency interference, the G/V tech was shall we say less than helpful. I'm no G/V expert but I can tell when a so called tech is holding back info as to help you solve your problem, and to me and others that is one of their problems.

I believe that a Hall Effect sender has 3 wires, 1 goes to ground, and a pulse generator has 2, mine are both 2 wire units. Either way the end result is the same just a different way of achieving a required vehicle speed signal to the brain.

If the voltage to the brain is less than 11 volts it scrambles the electronics much like radio frequency interference will from your ignition system, this is why I use a delay relay to supply the 12 volts directly from the battery.


Am I an expert? ....No way, but I have learned a thing or two about these units and making them operate thru self education and help from my electronics savvy buddies over the last 18 years.

[Sheepdip]

Originally Posted by 68Gold/white

Sooo, the overdriven ratio in the GV units is .78:1 ??? Is it the only ratio available???

I believe so.

[HO455]

Originally Posted by Sheepdip

You are very correct in G/V's tight lipped about anything to do with their products, which I think hampers them from selling more units.

The first major problem I had that I had which turned out to be radio frequency interference, the G/V tech was shall we say less than helpful. I'm no G/V expert but I can tell when a so called tech is holding back info as to help you solve your problem, and to me and others that is one of their problems.

I believe that a Hall Effect sender has 3 wires, 1 goes to ground, and a pulse generator has 2, mine are both 2 wire units. Either way the end result is the same just a different way of achieving a required vehicle speed signal to the brain.

If the voltage to the brain is less than 11 volts it scrambles the electronics much like radio frequency interference will from your ignition system, this is why I use a delay relay to supply the 12 volts directly from the battery.


Am I an expert? ....No way, but I have learned a thing or two about these units and making them operate thru self education and help from my electronics savvy buddies over the last 18 years.

That's good information I will shift my 12v positive over to the isolated power lead I ran for my A/F meter.
Thank you.

[68Gold/white]

Originally Posted by 72LB

Does anyone have a 3:08 gear behind theirs? I've been thinking about putting a Gear Vendor behind my TH400 but thinking the gear is to high.

Your engine, and it's specific build, tire size, etc... will have an effect on whether you can run that gear.

I would NOT want to go less than 350 cubes...and needs to be an engine that has fairly good power in lower RPM range.

[72LB]

Originally Posted by 68Gold/white

Your engine, and it's specific build, tire size, etc... will have an effect on whether you can run that gear.

I would NOT want to go less than 350 cubes...and needs to be an engine that has fairly good power in lower RPM range.

It's a 300hp 350, TH400, 28" tall tires.

[Sheepdip]

Originally Posted by 72LB

It's a 300hp 350, TH400, 28" tall tires.

Your 3.08 rear gears final drive would convert to 2.40 +/- in O.D., your 28" tall tires would give you just over 1600 rpm's at 55 mph or 89 kph