Driveshaft again..

[PattBlue]

Okay..this must be driveshaft week. Ever since I bought my Blazer I did'nt like the sound, feel, or vibration of the driveline. So since then I have changed rear pinion,seals,u-joints etc. Last week I was touching up the body, changing oil, checking battery, antifreeze, belts, touching up paint and having the whole thing oiled underneath, for winter ( Don't tell anyone one but I had to drive my father-in-laws Do*ge while he was in Florida.) Anyway I took out the rear driveshaft took it to the best LOCAL driveline shop. They spun it said it was bent .0005 of a inch, cut it off, replace it spin it, balance it, and put on new Spicer u-joints. I put it in expecting it to drive like a Cadillac (not really) It doesn't.
When I stop for a stop sign, and step on the gas KINDA hard I feel a THUMP ,THUMP,THUMP, under my console, if I start reguklar there is a SLIGHT vibration until about 5 Mph. So now whats the deal..and don't tell my wife its more money...
It's a 1990 stock except for 2 inch lift. 350, auto. TIA

 

[BorregoK5]

I've been playing with my pinion angles lately and thats the exact symptom I get when my rear pinion has less of an angle than the t-case side of the shaft. I'm not suggesting that you equalize your angles but you may want to change some of the angles and see what results you get. I had a bent shaft in my k5 with unequal pinion angles and it was vibration free, when I shackle flipped the rear my angles changed and I had the exact vibration you have. I angled the pinion back down by shaving my 2" blocks and it vanished.

I started with nothing and I still have most of that left! - <a target="_blank" href=http://www.echobit.com:81/k5/> Pictures</a>

 

[kpanza]

I'm assuming you have the 241 case with slip yoke - did you line up the splines with the flat spot when you put the driveshaft back on? Also, you might try putting a small amount of anti-sieze lubricant on the splines before putting it into the tailshaft housing - this worked for me when I had a similar thunk when coming to a stop and upon acceleration.

 

[90K5]

For some reason, there was a flat spot on my driveshaft, but not on the case, or vice versa...how do you line it up?

90K5

 

[PattBlue]

I always put a heavy grease in the yoke to stop it from THUNKING..It doesn't do that anymore..it did. I didn't know you had to line them up. Yes its a NP241..please explain.