Gear Vendors Overdrive Review
10-04-2009, 01:42 PM
#1
Racer
Thread Starter
Gear Vendors Overdrive Review
While this unit was actually put in my 1968 Firebird I know there has been interest in this versus a 5 speed swat on this forum as well. All of the analysis, etc is directly applicable to a vette and I was considering one for my 1969 before this install. In summary, go for the 5 spd. This is not worth it for the following reasons.
1. It was represented as a direct bolt in and about a 1/2 day job. It was anything but. It would not fit in the tunnel and required major cutting and modification to the tunnel to get it high enough to prevent driveline phasing problems.
2. The muncie 4spd shifter was supposed to bolt directly to the unit. It didn't because my car had a console and they use a different bracket on the hurst shifter for that. Gear vendors was no help at all on this and sold no adapter to make it work. We had to custom make a shifter bracket.
3. They send you a button to supposedly put in your shifter ball. The button is huge and there is a chance in hell it would ever mount to your shifter ball. They do sell a T handle shifter separately and for and extra charge but I don't like a T handle and they never said a peep about the button not fitting in the shifter ball. I had to rig it to a dimmer switch on the floor.
4. One of the advertisements of the unit was that it gave you a clutchless shift that was supposed to save signficant time at the strip. What a joke. How do you shift it with a dimmer switch on the floor and still clutch the car? Moreover, they said to depress the clutch half way when engaging it in the instructions. This was NEVER mentioned in the numerous conversations I had with them before purchase.
5. The reason they want you to depress the clutch half way is because this unit engages SO HARD that it nearly rips out the drivetrain in the process. I was expecting a nice clean engagement akin to a good automatic transmission shifting gears. FORGET it. This thing slams so hard it sound like the rearend is being torn out of the car. I have to let of the gas, then engage, and then reapply the throttle to keep from blowing the rearend apart. So much for a CLUTCHLESS shift even if I could use the button as I have no idea what doing this a few times would leave left of my driveline u joints and ring and pinion.
6. Likewise, using it to go in and out of overdrive while driving is similarly useless for the same reason. The whold car lurches on disengagement just like engagement.
The only thing worthwhile on this unit is to use it on the highway for overdrive. There is does make a substantial difference gaining me 5 mpg approximately. Saw consistent 18-21 mpg traveling at 75-80 and one tank of 22.75 mpg.
In comparison to a sure fit 5 spd swap this thing isn't even in the ball park. It is nearly as expensive and as stated above has serious drawbacks. Maybe thats why there original market was motorhomes and automatics. For a 4 spd vette or muscle car. Forget it.
Mike
1. It was represented as a direct bolt in and about a 1/2 day job. It was anything but. It would not fit in the tunnel and required major cutting and modification to the tunnel to get it high enough to prevent driveline phasing problems.
2. The muncie 4spd shifter was supposed to bolt directly to the unit. It didn't because my car had a console and they use a different bracket on the hurst shifter for that. Gear vendors was no help at all on this and sold no adapter to make it work. We had to custom make a shifter bracket.
3. They send you a button to supposedly put in your shifter ball. The button is huge and there is a chance in hell it would ever mount to your shifter ball. They do sell a T handle shifter separately and for and extra charge but I don't like a T handle and they never said a peep about the button not fitting in the shifter ball. I had to rig it to a dimmer switch on the floor.
4. One of the advertisements of the unit was that it gave you a clutchless shift that was supposed to save signficant time at the strip. What a joke. How do you shift it with a dimmer switch on the floor and still clutch the car? Moreover, they said to depress the clutch half way when engaging it in the instructions. This was NEVER mentioned in the numerous conversations I had with them before purchase.
5. The reason they want you to depress the clutch half way is because this unit engages SO HARD that it nearly rips out the drivetrain in the process. I was expecting a nice clean engagement akin to a good automatic transmission shifting gears. FORGET it. This thing slams so hard it sound like the rearend is being torn out of the car. I have to let of the gas, then engage, and then reapply the throttle to keep from blowing the rearend apart. So much for a CLUTCHLESS shift even if I could use the button as I have no idea what doing this a few times would leave left of my driveline u joints and ring and pinion.
6. Likewise, using it to go in and out of overdrive while driving is similarly useless for the same reason. The whold car lurches on disengagement just like engagement.
The only thing worthwhile on this unit is to use it on the highway for overdrive. There is does make a substantial difference gaining me 5 mpg approximately. Saw consistent 18-21 mpg traveling at 75-80 and one tank of 22.75 mpg.
In comparison to a sure fit 5 spd swap this thing isn't even in the ball park. It is nearly as expensive and as stated above has serious drawbacks. Maybe thats why there original market was motorhomes and automatics. For a 4 spd vette or muscle car. Forget it.
Mike
10-04-2009, 06:12 PM
#2
Tech Contributor
My buddy has one in his 78. It bolts in place of the Muncie tailhousing.(yes this has a muncie,nothing is original on the car) The driveshaft is huge and short. His was controlled by switches on the dash. I don't know how it was show horned in place or how he got it back out but he did. The muncie is an M-22 as well and I plan on rebuilding it soon once he decides on if the GV is going back on. I remember in the 70's they used a long handle in the passenger foot well to engage the OD. Somewhere I have pictures of that.
I agree a 5 spd is a better option.
I agree a 5 spd is a better option.
10-04-2009, 07:17 PM
#3
Race Director
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There is no question the 5-speed is a better option. The GV unit is great for full length vehicles such as motorhomes, and we have installed many of them for those applications. But a short car with a short driveshaft introduces other problems - not the least of which is the pinion angle.
Reducing driveshaft length on one that is already short can only cause trouble. Don't do it.
Gear Vendors is only a few miles from me and I used to work with one of their sales people who installed one on his WS-6. He has all kinds of vibration problems because of the shortened driveshaft. He should have just installed one of the pontiac 6-speeds.
Reducing driveshaft length on one that is already short can only cause trouble. Don't do it.
Gear Vendors is only a few miles from me and I used to work with one of their sales people who installed one on his WS-6. He has all kinds of vibration problems because of the shortened driveshaft. He should have just installed one of the pontiac 6-speeds.
