6speedblazer Posted July 4, 2016 Report Share Posted July 4, 2016 Still seems like it could be a pinion angle issue. What were the problems before amd what did you address on the pinion angle side? Quote Link to comment Share on other sites More sharing options...
JHForman Posted July 4, 2016 Author Report Share Posted July 4, 2016 Also just thinking out loud here, is there a possibility I'm getting into a resonate frequency of the chassis and maybe I'm hearing the exhaust vibrating on the frame? I have a spot where it touches it will be fixed next time I have the down pipe out Quote Link to comment Share on other sites More sharing options...
JHForman Posted July 4, 2016 Author Report Share Posted July 4, 2016 My pinion angle issue was with the rest drive shaft, I ended up using 2 degree shims on the axle and 3/4" spacers under the transfer case. The truck used to shake so bad I couldn't go over 70 mph this all happened after it was lowered now it's got a different case/trans and a different trans with a shorter rear drive shaft Quote Link to comment Share on other sites More sharing options...
JHForman Posted July 5, 2016 Author Report Share Posted July 5, 2016 I know they say not to remove the front drive shaft because of the viscous coupling, can I remove the rear drive shaft and go for a drive? Quote Link to comment Share on other sites More sharing options...
eberhama Posted July 5, 2016 Report Share Posted July 5, 2016 ... and 3/4" spacers under the transfer case Maybe I'm reading this wrong, but you have a 3" block under the tranny mount, to raise the t-case towards the floor to correct the rear pinion angle? Wouldn't that raise major hell with the front d/s angle? Quote Link to comment Share on other sites More sharing options...
JHForman Posted July 5, 2016 Author Report Share Posted July 5, 2016 .75" 3/4" not 3 inch lol it only changed the front angle by 1.5 degrees Quote Link to comment Share on other sites More sharing options...
eberhama Posted July 5, 2016 Report Share Posted July 5, 2016 ok, i'm dumb...i admit it. Just out of curiosity...have you ever had the front shaft spun to make sure its straight? Quote Link to comment Share on other sites More sharing options...
JHForman Posted July 5, 2016 Author Report Share Posted July 5, 2016 I have not, I'm heading that route it seems though Quote Link to comment Share on other sites More sharing options...
JHForman Posted July 6, 2016 Author Report Share Posted July 6, 2016 So for shits and giggles tonight I decided to take the shims out entirely, my transmission points down at 7 degrees and my pinion points up at 7 degrees, I test drove it and it's the best it has been yet!!!! Now this goes against absolutely everything I have read about pinion angles everything I have read said you want a 2-3 degree split to account for the pinion rotating upwards under acceleration and when I set my pinion that way this vibration is terrible. So my question is now do I order a set of 1 degree shims and try them? Or is it as good as it's going to get ? I have tried shims from 2-6 degrees. My vibration was from 75-90mph then would go away. After getting rid of shims all together my vibration is a very small range 70-75 mph. So what should I do? Quote Link to comment Share on other sites More sharing options...
JHForman Posted July 6, 2016 Author Report Share Posted July 6, 2016 Today I removed the rear shaft and went for a drive there's absolutely 0 vibration with the shaft removed so now I've at least isolated it to the rear shaft. I called tom woods today(very helpful people) and they said it's a balance issue. But apparently it's hard to get the shaft balanced with the slip yoke installed they said most shops can't do it and just balance the shaft itself. So now what do I do? Quote Link to comment Share on other sites More sharing options...
Downeast Johnny Posted July 6, 2016 Report Share Posted July 6, 2016 Today I removed the rear shaft and went for a drive there's absolutely 0 vibration with the shaft removed so now I've at least isolated it to the rear shaft. I called tom woods today(very helpful people) and they said it's a balance issue. But apparently it's hard to get the shaft balanced with the slip yoke installed they said most shops can't do it and just balance the shaft itself. So now what do I do? Congratulations on narrowing it down this far. I can see where it would be tough to balance both together. How about balancing the yoke by itself and then the shaft? Quote Link to comment Share on other sites More sharing options...
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