Over / Under drive units ? Anybody running one of these ?

[thepcsurgeon]

I used the under/gear splitting once or twice. The procedure is a little clumsy si I don't use it. When I mash the go peddle, I manually shift really fast so it's really useless for me. The auto engage works pretty good also. It is a firm shift. I'll take some pictures tomorrow and post them. There are a few youtube videos of a guy gear split shifting.

 

[87BlazeLS]

Thanks pcsurgeon, So your unit has over drive and under drive all included ? Is this the way
they all are ? Did you have to shorten the drive shaft or alter the front yoke ?
You car looks rather stock, is it more of a sleeper? Can't wait to see the surprise....

 

[Texas82GP]

I see your GP used to be a diesel. The 350 version?

Yeah it came from the factory with the Olds 350 diesel. When I bought it, it had a SBC 400 and a four speed Saginaw. Unfortunately the conversion was not well executed so I'm doing a drivetrain restoration.

It would seem from texas82 response earlier that much of the issue was them not telling him all the required details until the ut oh.

My gripe with Gear Vendors is when I bought the "kit" from them they acted like it was an engineered solution and would bolt right in. Then they get mixed up between the T10 and the toploader on what will work and have me wasting money and precious Saturdays spinning my wheels. I have a short output shaft for a Mustang T10 I can't use and can't sell. Wasted money. I tore down the the T10 and put the shaft in it and couldn't use it so that's a bunch of wasted time putting the T10 back to where it will work in the car. I rebuilt the toploader only to discover that was the transmission that needed the short shaft. More lost time and effort. Dad is not a young man and I'm trying to help him finish and enjoy the car. When you are spinning your wheels like that it isn't fun. My impression of Gear Vendors is they will tell you whatever they have to in order to get the unit sold to you. We will get the unit in the car and in the end it will likely be well worth it but the experience has sucked. I would imagine they have some well engineered setups for more popular applications but in my opinion it is "buyer beware." Short of really high horsepower setups, I can't see putting one in something like our cars where you can put a built 700R4, a built 200-4R, a 4L80E or a Tremec.

 

[thepcsurgeon]

My car is stock in appearance, sort of. The cowl hood and loud exhaust hint that something nasty is under the hood. That's the way I like it. HEHEHE.....
The over/under is the same unit. A new yoke is included because it is very specific to the GV unit. The drive shaft will have to be shortened. But it bolts up to the crossmember. The installation manual is 30 plus pages. I would order the manual first and realize the work involved. Not hard to install, I did it all by myself without any other helping hands.
The reason went this direction is because of the horsepower I put down to the rear wheels. But I also like to drive it casually and not have to trailer it everywhere. The transmission is a B&M race transmission TH 400 and very stout for my application. A 2004R, 700r4 is not strong enough for my present HP needs, but I may look to a custom 4L80e or something else in the future. I have blown up 3 transmissions in 2 years, I even killed the sprag three months after the transmission was installed. HTH

 

[87BlazeLS]

Interesting pics there pcsurgeon, So from what I see your Gv unit attaches to your TH 400
minus the stock tail shaft ? Are you running the TH 350 /400 cross member ?
And you said the GV bolts to the cross member ? if so does it use a rubber mounting bushing there ?
I see one of the pics shows a contact area is that where you bent the floor up a bit? if so it looks very slight....

Clean install to me. Next if you can please show how things work on the shifter end of your cars console.

Great work man. And thanks for the pics and up date. Some folks on here are taking notes.
Oh , one other thing. Is the unit controlled electrically by the wires running to the unit or
is it controlled by a cable coming off the side? I thought that might be your speedo cable.

 

[87BlazeLS]

Interesting pics there pcsurgeon, So from what I see your Gv unit attaches to your TH 400
minus the stock tail shaft ? Are you running the TH 350 /400 cross member ?
And you said the GV bolts to the cross member ? if so does it use a rubber mounting bushing there ?
I see one of the pics shows a contact area is that where you bent the floor up a bit? if so it looks very slight....

Clean install to me. Next if you can please show how things work on the shifter end of your cars console.

Great work man. And thanks for the pics and up date. Some folks on here are taking notes.

 

[thepcsurgeon]

Electrically controlled. A toggle switch placed near the shifter (Ugly looking rocker but will be replaced soon. two small lights to indicate if the unit is engaged or disengaged. The Crossmember mount uses a regular transmission mount or solid, your choice. A floor switch to turn the unit on. The google switches between manual or auto and the floor switch (Old headlight bright switch style) turns the unit on/off. Pretty simple. A few easy wire connections and your on your way. Here are some Google pics I found: