Installing Klune V underdrive to t-150?

Installing Klune V underdrive to t-150?

ozelot250

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Yuma,AZ
I have a 1978 Jeep CJ7 304 V8, 3 speed T-150 stock, 3 inch lift, 33x12.5x15 AT tires, HEI ignition. I think it has 3.54 gears or 3.73 don't know for sure. This is my very first jeep. It is not my daily driver but a weekend toy. It currently handles very nicely on the street but I would like to make it more versatile off road and still keep its road manners. I currently don't plan to do any heavy rock crawling but I do take the jeep out on desert trails and the Glamis/Imperial sand dunes. I live in Yuma,AZ for those who are familiar with the area. I do feel I could use more power as the truck feels bogged down going up the steeper dunes or on steep rocky trails I feel it doesn't have enough "grip". I'm pretty happy with the on pavement performance, it drives straight and cruises comfortably at 70+mph. I wish i had one more gear though as I feel the T-150 is too highly geared.

I was interested in the t-18 wide or close ratio. The low gear in the wide ratio could come in handy but I probably would rarely use that low of a gear. The close ratio t-18 gives me a 4.0 low vs the T-150 2.99, a fourth gear and a better spread. I was thinking instead of swapping trannies, gears and such what if I kept everything the way it currently is and instead install a KLUNE V underdrive? That way I wouldn't need a "Low" first gear or low low gear transfer case. The Klune should give me the versatility off-road that I am looking for right? I would also have low grawling ability even with my stock tranny right? Your thoughs and ideas are welcomed. Rob
 
I don't know for sure because I haven't tried to install one my self, but
the main thing that concerns me about this project is the rear drive line length. A Wrangler or CJ doesn't have much of a rear driveline to start with, and here we were supposed to insert a 6-½ inch gearbox in between the transmission and transfer case! The 6 cylinder Wrangler YJ with the AX15 transmission comes from the factory with about a 13" driveshaft a CJ7 is similar & CJ5 is shorter.

There are two problems you run into with a short drive shaft:

The first is vibration. This may not be very important to those who trailer their rigs to the trail, but this Jeep will be driving on the interstate for hours at a time. Vibration is caused when the various angles the parts of the driveshaft operate at do not line up correctly or simply have too much angle. Minimize drive line angles, use a CV joint and make sure everything is set up with correct geometry i.e. shaft angles, and there will be no vibration. Vibration can damage U-joints, bearings, seals & generally annoy the :dung: out of you. Vibration measurements are made with the vehicle sitting at ride height, as that is where it will be when it is driving down the freeway.

The second problem comes about when you get full extension, or droop, of the rear suspension. This can cause the joints in the drive shaft to physically bind. If this happens while the vehicle is under power, the driveshaft will most likely break. You must make sure the drive line does NOT bind when the rear suspension is at full droop, as with the vehicle on a lift.
 
Thanks I wasnt aware of the driveline issue. Still, what do you think about the concept? With the Klune under drive I wouldn't have to swap trannies,differential gears, low transfer case gears, right? The Klune could replace all that right?
 
I have a 1978 Jeep CJ7 304 V8, 3 speed T-150 stock, 3 inch lift, 33x12.5x15 AT tires, HEI ignition. I think it has 3.54 gears or 3.73 don't know for sure. This is my very first jeep. It is not my daily driver but a weekend toy. It currently handles very nicely on the street but I would like to make it more versatile off road and still keep its road manners. I currently don't plan to do any heavy rock crawling but I do take the jeep out on desert trails and the Glamis/Imperial sand dunes. I live in Yuma,AZ for those who are familiar with the area. I do feel I could use more power as the truck feels bogged down going up the steeper dunes or on steep rocky trails I feel it doesn't have enough "grip". I'm pretty happy with the on pavement performance, it drives straight and cruises comfortably at 70+mph. I wish i had one more gear though as I feel the T-150 is too highly geared.

I was interested in the t-18 wide or close ratio. The low gear in the wide ratio could come in handy but I probably would rarely use that low of a gear. The close ratio t-18 gives me a 4.0 low vs the T-150 2.99, a fourth gear and a better spread. I was thinking instead of swapping trannies, gears and such what if I kept everything the way it currently is and instead install a KLUNE V underdrive? That way I wouldn't need a "Low" first gear or low low gear transfer case. The Klune should give me the versatility off-road that I am looking for right? I would also have low grawling ability even with my stock tranny right? Your thoughs and ideas are welcomed. Rob
Thanks I wasnt aware of the driveline issue. Still, what do you think about the concept? With the Klune under drive I wouldn't have to swap trannies,differential gears, low transfer case gears, right? The Klune could replace all that right?
 
Thanks I wasnt aware of the driveline issue. Still, what do you think about the concept? With the Klune under drive I wouldn't have to swap trannies,differential gears, low transfer case gears, right? The Klune could replace all that right?

Rodger that.
I've seen them installed in fullsize pickup trucks & they seem to work well.
 
Thanks saddletramp, I'm just trying to get the most bang for the buck and the most versatility with the least fewest mods possible. There is a guy near me who happens to have a Dana 20 with a 3:15 Tera low kit for $900 that I'm considering as well.
 
I believe the tranfer case gears would be the way to go, no driveline mods, and you can save some money buy buying the gears and installing them yourself rather than buying that whole other case. Lomax gears from jb conversions run a little less than $700 and they seem to be "beefier" than the teralow kit

Sent from my DROID2 using Tapatalk
 
I think I'm going to keep it simple and go with a t-18 swap with a D300 or Dana 20 with a 4 low or 3.15 low gear kit. The low first gear will give me a very respectable crawl ratio and the other three gears in the t-18 should be identicle to my T-150. A neighbor is selling a running t-18 wide ratio out of a 1975 ford f150 and asking $150. This should bolt right up to my amc 304 v8 without any adapters. Unfortunately it looks like i will have to get an adapter for the Dana 20 or d300, it doesnt come with a transfer case.
 

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