KieserWillys overdrive

I have a '67 CJ6 with V6 and T86 3 speed tranny. The jeep drives and runs fine however Top speed is only 45 mph. I know that these old jeeps were not built for speed but I would like to get going a little faster. I was looking at the KeiserWillys overdrive that they offer. ($1000.00+) they claim it will increase your speed by 25%. But before spending the money I wanted to see if anyone had purchased or used this before. If they felt it was worth it or not. I was also concerned about intalation, the overdrive unit itself looks fairly easy to install, but what about the shifter? I suppose I will need to cut a whole in the floor board between the seats. Has anyone done this before?

 

I am wondering what axle gear ratio you have? I have the 4.88 gears in mine and can easily go 70+ without the overdrive.
The overdrive make my jeep much more enjoyable to drive at highway speeds. It keeps the Rpm of the engine lower and not rapped out.
I am wondering about your top speed. Something's not right.

 

This would fit, no shifter holes, and a LOT cheaper.

http://www.earlycj5.net/forums/showthread.php?111329-T-90-Dana18-and-overdrive

 

Tire size is 215/75r/15, transmission has been rebuilt, and I have 3.73 gears, speedomoter is jumpy at best so cannt really get an accurate reading, GPS on phone app says 45 mph. I still have pedal left to give so I guess I could go a little bit faster but sounds like the Trans is winding out.

 

Yes flatyfreek I saw that post the other day. He doesn't mention what brand or name for the overdrive so not sure what to look for.

 

The Warn/Saturn overdrive is a great addition. It also depends on your axle ratio. If you have 3.73 gears, it is not needed as much ( to go highway speeds) as much as if you have a lower ratio such as the 4.88 or 5.38 axle gearing. It also has a second benefit of alowing you to split each gear to find just the right gear for the speed you want on the trail.

Picture before shifter


After shifter installed



Not very hard to install the shifter as there is already a cut out for it.

The above other overdrive that is for sale would require driveshaft modification and would only work in 2WD. The Warn is the bomb if your wanting an overdrive.

If you have 3.73 gears something is definately not right. Highway speeds should be easily doable.

 

Cool thanks for the pictures Mark K.
As mentioned before, I've had the transmission rebuilt, I wonder what could be holding it back, or a least it feels like something is. Any thoughts?

 

Look at a calculator such as on Randys R&P website. For your tires and gear ratio, you would be turning 2717 RPMs at 60 mph. Not bad- the V6 should handle that easily.

Outside of re-checking your gear ratio the only thing I can think of is maybe someone has pulled the interlock out of the transfer case so you can run it in low range 2wd and that is what you are running in. Seems like a long shot....

 

It's a Borg Warner. They were an option in the wagons and pickups. I bet a CJ5 driveshaft would be real close in making this fit. If your happy with your off road performance right now, you won't need 4WD overdrive. With 3.73 gears, you shouldn't need one anyway.

As far as what you are describing, did they rebuild the transfer case as well? If they didn't, it's possible that the intermediate shaft shaft and bearings are worn. When they wear, the transfer case whines like an 8 year old. You also need to install a tach to see what your true RPMs are.

 

No transfer case was not rebuilt, just tranny, and yes it whines when driving. I do not use it off-road, I use it about 3 times a week or so for going to work and running to the store.
Am I doing it any further damage by driving it this way?

 

Are you sure that your transfer case in in high range?

 

The shift lever is pushed all the way forward toward the engine, when driving I can see that my front driveshaft is not turning at all.

 

The diagram I am looking at shows the Dana18 transfer case with two shift levers, I only have the one like Mark K has in his first picture that he posted on this thread, however, the t-case is stamped Dana18

 

have you used low range yet? You will certainly notice a difference. If there is no difference then something is wrong with your shifter

 

No I can't say that I have, when I get home from work I'll hop in it and go through the gears.

 

I guess it is possible that when I put the shift lever back on the TC could've been in a different gear than I thought it was. When driving in 2wd, in what position should the shift lever be? I thought all the way forward toward the engine was 2wd, one click back was 4L another click back was Neutral and all the way back was 4H.

 

Oh my. I knew a guy whose girlfriend took his truck 40 miles in low range - on the interstate.

 

Well I'm sure I haven't been driving it in 4L, if the t case was in neutral I wouldn't be able to go anywhere. The front driveshaft does not turn when driving so it must be in 2wd. Transfer case must need some work done to it.