I'm having some trouble fellas, I have a 94 Blazer full size I recently put a 6" lift on it. Since then I or the mechanic that did my shift fork broke the housing on the transferase, fixed that, now the housing on my transmission cracked nearly all the way around. Does anyone or had anyone ran into this problem after lifting their rig. Any help will be appreciated.

 

This should help: http://www.4xshaft.com/driveline101.asp

 

Les thanks I read your whole post, but I'm still not sure how to fix this I went and bought an angle finder to see what the degrees are on each component, the rear diff (8°), drive shaft (17°) and back of transferase (5°). I need to do something to bring down the degrees on the drive line and get the other two a little closer. I can't drop the t-case so it's either something like wedges under the rear blocks or a dbl cardin joint. IDK

 

I imagine the measurements you took are relative to level. Rear diff 8° up in front, back of transfer case 5° down, back of driveshaft 17° down. With the 6" drop, the front u-joint angle is now 17°-5° = 12° and the rear u-joint angle is now 17°-8° = 9°. Ideally these would be equal, closer to zero, and opposite (which they are) so they cancel each other out, but I also read more than one place that 15° is the upper limit for a u-joint angle on a lifted truck and yours is below that. The difference between the u-joint angles and the fact that they are both at a quite high angle might cause some vibrations but I doubt they should be breaking parts - just wearing out u-joints more rapidly. Are you running out of driveshaft length when suspension travels (shaft becoming too short or too long)?

Honestly, I would suggest calling the manufacturer of your lift kit for advice. Bet they have seen the same thing before. There is no problem new under the sun, if you are exposed to enough problems!! This is where extensive experience can really help. Also of big help might be a 4x4 truck shop that does lifts all the time.

Good luck and best wishes for a successful repair. Do let us know when you get it figured out. I'll be interested in knowing the cause and the solution.

 

I contacted the lift kit manufacturer (rough country) and according to them the angle is figured in to the block itself that so the info they had, only other thing was if the installer put the lift block backwards but it's not. But yes the shaft is now allot further out then what it used to be. I'm completely lost in this can't use my Blazer, can't really find a transmission cause I was told I can only use one from 93-94. I'm holding off on that double cardin shaft cause it's pricey ($600) it shouldn't be this much trouble just lifting 6" I have a 69 Chevy 4x4 that has a pretty steep angle and I have no problems there, infact I'm going to measure those angles today after work see what those are.

 

It sounds like the driveshaft splines might not have enough engagement in the back of the transfer case, so the shaft is moving around and putting stress on the housing.

 

Just be aware that if you use a double cardin driveshaft you will need to point (shim rear axle) the pinion at the transfer case yoke so the rear u-joint operates at 0° angle (the double cardin joint itself is net zero angle no matter where you point the other end). I wouldn't buy one unless you can definitively attribute your breakage to the driveshaft/u-joint angles or driveshaft that you have.

Per TomA's post - does your driveshaft have a slip yoke that goes into the back of the transfer case, or does it have a fixed yoke into the transfer case and a slider setup in the middle of the shaft? He may have hit on the problem. Where exactly did the transmission crack?

also maybe discuss your problems with the author of that article I linked to? He has a phone number for his shop at the end of the article.

 

I'll just add that he's a really nice guy, super helpful, and very knowledgeable. Builds damn fine driveshafts, too. Just in case you end up needing to buy one.

 

Rock Auto says the rear driveshaft is 35" and has a slip yoke that goes into the transfer case. Using the Pythagoean Theoem, a 10" lift would pull the yoke back 1.4" out of the transfer case if the transfer case remains in the same position as before. Don't know if that's enough to cause a problem or not, or if the transfer case has been moved or not during the lift.

Hey, FYI I like the following freebie app for measuring driveshaft angles. You can get it off of Google Play: Clinometer

 

Yeah not sure what's going on the bushing and rear seal came out too,

Bushing and rear seal look how far that shaft is out