Gear Vendors Overdrive

[Ptjsk]

After getting my Jimmy on the road, I was a bit concerned as to the drive-ability of the Truck.

I had rebuilt the motor, stroked it to a 383, and rebuilt both front and rear axles, as well as the 350 transmission.

Additionally, I installed Tru-trac posi units in both front and rear. Since I was going with 33" tires I thought 410 gear ratio would be the best.

After I finished I wasn't totally happy with trying to go 65 mph as the motor was rotating a bit above 3000 rpms.

I contemplated going with the overdrive transmission, but my transmission guy talked me into keeping the T350. He said they're just a great old (strong), transmission.

I began to look at the Gear Vendors for an overdrive unit. I probably had about a 50/50 response as to those saying it would work, and those saying it wouldn't work due to the short wheel-base.

Finally, I decided to take the plunge and just see for myself if it would work.

Then followed it up a Tom Woods driveline. These guys were super helpful and gave me guidance on rear end shims (6 degrees), and built a short driveline with a CV joint on the front end.

Happy to say, the Jimmy performs flawlessly! No vibration and most importantly, I can cruise along at 70-75 mph with no problems at all. The motors just cruising along now.

The only problem I have now is that I'll probably have to install one in the step-side!

Anybody have apprehensions with going this route need not worry. It will work!

Gear Vendors themselves are very helpful and can't say enough about Tom Woods drivelines!

Pat

[DeadheadNM]

Great info. Thanks for posting. Pics when possible please.

[Ptjsk]

Here you go!

[DeadheadNM]

Very nice. How do you operate 4wd then if the GV unit services just the rear axle?

[praisegeetarman]

Originally Posted by DeadheadNM

Very nice. How do you operate 4wd then if the GV unit services just the rear axle?

With GV you use overdrive in 2 wheel drive only

[DeadheadNM]

Is there a switch then to activate the OD as desired?

[jayoldschool]

Originally Posted by praisegeetarman

With GV you use overdrive in 2 wheel drive only

I think it would have made more sense to go with a 4WD 4L60/65/80.

[praisegeetarman]

Originally Posted by DeadheadNM

Is there a switch then to activate the OD as desired?

My buddy had one of these a while back. His used an actual old school dimmer switch on the floor in the stock location to activate the overdrive.

[DeadheadNM]

Thanks - I didn't realize the overdrive had an "on/off" switch so to speak. Doesn't seem like a bad way to go - probably less fuss involved than the 700R4 swap we did in my K20.

[Ptjsk]

Originally Posted by DeadheadNM

Thanks - I didn't realize the overdrive had an "on/off" switch so to speak. Doesn't seem like a bad way to go - probably less fuss involved than the 700R4 swap we did in my K20.

Definitely a few different ways to go. The 700R4 may not be a bad deal as well.

Fortunately, I'm happy to say that this meets and exceeds my expectations and makes the Jimmy much more enjoyable to drive.

It is designed to operate while in 2 wheel drive. Doesn't seem to be a problem to me as I can't ever remember needing to go over 40 mph, or so while in 4 wheel drive.

The on/off switch works pretty darn good. Should I want, or need an additional gear, I just turn the unit on and utilize my pull switch.

Pat

[kwmech]

Drive shaft looks too short to me. How far does it go into the back of the GV

[jjzepplin]

Interesting. I also cannot say enough about Tom Woods. Great company! When I installed my NP203 splitter and 1 ton axles they hooked me up. Pricey but absolutely no vibrations. They also suggested the Flat Furd flange for the NP205 and a bolt on the flange Cardan Joint (Spicer of course). Built in 2000 and still works great.

[Ptjsk]

Originally Posted by kwmech

Drive shaft looks too short to me. How far does it go into the back of the GV

The shaft of the gear vendor sticks out of the housing approximately 1" which is obviously hidden by the yoke.

The inside of the housing bottoms out at 3". So the end of the yoke is held back about an inch so there's plenty of room for "sliding" movement with suspension activation.

Pat