Driveshafts and Lift
 

I have a 72 Jimmy been doing a frame off job on for some time now...anyway I`m to the point where I need to decide on a 2" or 4" suspension lift, I have 2" of body lift in it already. Could someone tell me if I `ll need to get my driveshafts lengthened with a 4" lift, and how bad will it be on u-joints since the Blazer rear shafts are so short and at a steep angle to begin with. Thank You

4" should be no problem. I had an 85 w/ 4" lift and it's driveshaft is shorter then what you have because of the NP208 transfer case's tailshaft.
Welcome to the board!

When I put a 4" lift in my Suburban I had to have the rear shaft lengthened. When I went to install the rear shaft after the lift I pulled the splines all the way out and I was about 1/2" from seating in the yoke. Obviously too short. The front shaft was fine.:D

I have 4" on my Jimmy and had no troubles with the stock rear shaft. I first had 1 1/2" add-a-leaves and 2 1/2" blocks but bent the axle housing perches! It now has a set of 4" National springs in the rear but I disposed of the EXTREMELY clapped out stock rear shaft for a Tom Woods CV joint rear shaft. The rear springs tilt the rear axle up to a virtually zero pinion angle which is correct for a CV shaft, but not for a non CV shaft. I had tossed my original shaft out a couple of times after breaking rear yokes and/or u-joints and it was tweaked as well as just worn from 300k+ miles. The new shaft elimintated about 2/3 of the slack in the driveline.

Thanks for all your input guys! Sounds like I`ll get by with my stock shaft lenghts and 4" of lift... in a old Jimmy anyway. Now I just have to decide, 33`s with 4" total lift or 35`s with 6" total. Decisions decisions!

35's of course. My truck looked supid with 33's I thought. 4.10s and the 33s was too much, but perfect for the 35s.

When I did my initial 4" lift on my '69 I did have to have the front driveshaft lengthened and even had to add a CV joint. But mine has the Rockwell T221 transfer case. From what I have gathered, usually a 4" lift on the years after they stopped using the Rockewell (after 69), don't need to have the shaft lengthened.

The NP205 trucks should come with a CV shaft in the front. At least the 3 I have had did.

Yep.

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Don't worry about U-Joint life too much, either. When I first lifted my heap, I was going thru U joints quite often. Then I discovered that my yoke was thrashed. After fixing that, the joints last for a couple years, or so.

Although thats a pretty short lifespan, when compared to a stock truck, they're cheap, and easy to replace...so, IMO, its no big deal. Well worth it, for the increrased clearance, traction, etc.

My beater has a 6" Lift in it, BTW.

-M

Mike, when you say zero pinion angle you mean perfectly horizotal right ?

that would explain why some trucks have perfectyl horizontal pinion and why some are tilted up/back a bit,....

hmmmmm.........