Pinion Angle
Well, I replaced both u-joints, with no success in getting rid of my 40-45MPH harmonic pulsating vibe, other then that everything else seems to be good to go, the last two things I can go and do now is get a no walk tailhousing bushing in hopes that that might get rid of it, but doubt it, or go to an aluminum driveshaft.
Na, I'm using a steel one from a 3rd gen, that I had ever since my stock one twisted on me....the funny thing along with me putting my buddies aluminum DS in and not getting anymore vibes, is that this steel one is the same one I used on my 10 bolt and it never made any noises.
I have the Strange chomeoly DS and I also cant get rid of the vibes. Right now they are barely annoying but I am making no progress. Mine starts at 55MPH and continues on up but does not really icrease in severity.
The rear joint has been replaced but not the front. The front is not loose but is not tight either. Figure what the Hell. I also have the Rockland bushing on the way.
I am still not convinced its the bushing causing the vibe. I can feel the vibes in the shifter like I figure I would if it really were the rear bushing.
This has me pissed off to no end. It did not do this until recently and I have lost track of when it started with regard to crap I have been working on.
The rear joint has been replaced but not the front. The front is not loose but is not tight either. Figure what the Hell. I also have the Rockland bushing on the way.
I am still not convinced its the bushing causing the vibe. I can feel the vibes in the shifter like I figure I would if it really were the rear bushing.
This has me pissed off to no end. It did not do this until recently and I have lost track of when it started with regard to crap I have been working on.
Thats the other very weird thing about my pulsation is that it's only in 5th gear at around 40-45MPH, everything before that and after that is smooth, with no vibes or anything all the way up to at least 120 for right now. (haven't gone faster then that with new rear yet)
You know that the d-shaft should be slightly longer with a 9inch? I know EPP went thru this with the Moser stuff and had vibration issues for awhile till they started using longer d-shafts. Just wanted to make sure you were aware of this.
I have the Strange chomeoly DS and I also cant get rid of the vibes. Right now they are barely annoying but I am making no progress. Mine starts at 55MPH and continues on up but does not really icrease in severity.
The rear joint has been replaced but not the front. The front is not loose but is not tight either. Figure what the Hell. I also have the Rockland bushing on the way.
I am still not convinced its the bushing causing the vibe. I can feel the vibes in the shifter like I figure I would if it really were the rear bushing.
This has me pissed off to no end. It did not do this until recently and I have lost track of when it started with regard to crap I have been working on.
The rear joint has been replaced but not the front. The front is not loose but is not tight either. Figure what the Hell. I also have the Rockland bushing on the way.
I am still not convinced its the bushing causing the vibe. I can feel the vibes in the shifter like I figure I would if it really were the rear bushing.
This has me pissed off to no end. It did not do this until recently and I have lost track of when it started with regard to crap I have been working on.
So, you did not have the problem right of the bat with this driveshaft setup?? I know you mentioned before in this thread just don't want to have to go and look for it in the last 3 pages.
I had my DS lenghtened 1" for my 9", CL/CL was 41.5 now it's 42.5 and has a 3/4 space between the tailhousing and the DS flange.
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Verdad Gallardo I ended up taking the DS to a shop to check thvbalance, so it has been altered some. I honestly believe it was golden from the get go. The rear joint was replaced but not the front. The front feels good, but it is going to be replaced tomorrow. The DS has nearly no runout too.
All your help and comments are very much appreciated.
I do not know the numbers off hand. If it were me I would give Eric a call with all your measurments just to see if he might see something that might be being overlooked?? I am trying to stay on top of this cause when I go to set my car up next month I am going to print this thread so I know what I need to do to hopefully avoid a vibration myself.
I also see nothing unusual to indicate the the new rotors would pose a balance problem.
Well all my problems are now solved, my thumping at 40-45MPH in 5 th gear was my gears, this pass weekend I was out with only about 700 miles on the rear and the gears started to whine really bad, louder then my true duals, well I took it all apart and seen the pinion was sheering away, must have been a bad heat treatment/quality control from the gear factory, got new gears and no more noises, thumping, cracking or anything.
Well all my problems are now solved, my thumping at 40-45MPH in 5 th gear was my gears, this pass weekend I was out with only about 700 miles on the rear and the gears started to whine really bad, louder then my true duals, well I took it all apart and seen the pinion was sheering away, must have been a bad heat treatment/quality control from the gear factory, got new gears and no more noises, thumping, cracking or anything.
Were these the gears from midwest that Eric set up for you? If so what did Eric do to help you with this problem? Also what gears were they? Brand and ratio.
Yes they were the gears that Eric setup, but just so there isn't any confusion, the pattern that he set up was a good pattern, it was just one of those things where the factory goofed up, they were Motive 4.11 grears too, he was going to just send me another sent, but I decided to go with a set of Richmonds 4.11 instead. Eric was very helpful in this matter and got the new gears to me with in a few days, so I was happy.
Ok on the subject of pinion angle...does this all add up?
1982 Z28, T56 w/ Moser 12 bolt. Lowered 1" from stock with Hotchkis springs.
Transmission Output Shaft Angle = -3 Degrees (pointed down)
Angle @ FRONT of driveshaft right next to u joint = 3.5 Degrees (pointed up)
A. Front u joint operating angle = 6.5 Degrees
Angle @ REAR of driveshaft right next to u joint = 3.5 Degrees (pointed down)
Rear Pinion Yoke Angle = +1.5 Degrees (pointed up)
B. Rear u joint operating angle = 5 Degrees
Pinion Angle = -1.5 Degrees
Driveshaft Length = 38.5" Center to Center of u-joints
Driveshaft runs "uphill" from trans to pinion as car is lowered!
1982 Z28, T56 w/ Moser 12 bolt. Lowered 1" from stock with Hotchkis springs.
Transmission Output Shaft Angle = -3 Degrees (pointed down)
Angle @ FRONT of driveshaft right next to u joint = 3.5 Degrees (pointed up)
A. Front u joint operating angle = 6.5 Degrees
Angle @ REAR of driveshaft right next to u joint = 3.5 Degrees (pointed down)
Rear Pinion Yoke Angle = +1.5 Degrees (pointed up)
B. Rear u joint operating angle = 5 Degrees
Pinion Angle = -1.5 Degrees
Driveshaft Length = 38.5" Center to Center of u-joints
Driveshaft runs "uphill" from trans to pinion as car is lowered!
