pinion angle set-up ('68 440 charger) UPDATE!!

[RECHRGD]

I'm trying to be sure that I'm at least close on my pinion angle before I get the car back on the road this spring.  It has not seemed quite right ever sense I installed the gear vendors unit a couple of years ago.  I've had a couple of shops try to fix it, but I'm not real confident that they knew what they were doing.  I've just put a new transmission in and it seems like a good time to fix this once and for all.  Right now it's got 4* shims in in the leaf spring perches that increase the nose down attitude on the 8 3/4" pig.  I've got a magnetic angle finder but am not sure how to get accurate readings.  The only spot on the engine that I can get to a flat spot is on the oil pan rim right underneath the block (440) on the drivers side and I don't know if that really represents the output shaft angle.  Where is the best spot to get an accurate angle at the pinion shaft?  There's a pretty flat area at the bottom of the pig that I used to get a reading, but, again, I don't know if it's accurate.  The car is on a 4 post lift and sitting on it's wheels.  What I came up with is as follows:


Output shaft (taken at oil pan)= 3* drop from front to back.
Drive shaft                          = 2* drop from front to back.
That should = Total 1* angle at the front u-joint.  Right?

Rear pinion angle (taken on pig flat spot)= 3* drop from back to front.
That should= A total 4* angle at the rear u-joint.  Right?

I've read that the output shaft and pinion angle need to be as close to parallel as possible, but the readings that I've got put them at a 7* angle and going opposite directions.  Any help would be greatly appreciated.  Thanks,  Bob

[firefighter3931]

Bob, here is a good tutorial on setting the pinion angle. 

http://www.moparts.org/Tech/Archive/axle/8.html



Ron

[RECHRGD]

Thanks Ron.  That's a good article.  I guess my main question is-----Are the points wear I'm putting the angle finder going to give me an accurate reading?  Thanks,  Bob

[Just 6T9 CHGR]

Curious to see if aluminum shims could be used or do they have to be steel?  can you stack them (stack (2) 2º shims?

Gonna really look into my angles this season as well...

[68n70]

When you say not quite right, what isn't right???  Just the angle?  I also have a '68 charger with a gear vendors and it hasn't been right either, with a bad vibration that I can't chase down.  I posted about this some time ago on Moparts and it was consensus that I probably need to go 2-3* pinion up!!  Haven't done it yet, but I'm curious if you have the same problem.   

[RECHRGD]

When you say not quite right, what isn't right???  Just the angle?  I also have a '68 charger with a gear vendors and it hasn't been right either, with a bad vibration that I can't chase down.  I posted about this some time ago on Moparts and it was consensus that I probably need to go 2-3* pinion up!!  Haven't done it yet, but I'm curious if you have the same problem.  

I had no vibration problems at all before putting in the gear vendors.  On my first drive after the installation, the g/v adaptor (tailpiece) was hitting the tranny support crossmember and creating a vibration and banging when it would shift.  I put several washers in the tranny mount to raise the tailpiece further off of the crossmember.  That made the car drivable, but I could feel vibrations at differing speeds, especially under acceleration.  One shop decided I needed to go to a 2* shim in the rear to bring the nose down more.  This didn't really seem to help.  Later I made some modifications (cuts) to the crossmember to eliminate the need for the washers.  I still had the problem, but the 2* shim was still in there.  I went to another shop and they took out the 2* and put in a 4* shim.  Same problem!  I think I'm going to just remove the shim altogether and see what happens.  Although removing the shim will take me back to about a 0* angle at the pinion, that's probably what I had before the g/v anyway.  So maybe your advice on moparts to go pinion up may the way to go.  I really should have taken some readings before I installed the g/v, like their instructions say to do.   Bob

[68n70]

I know I researched it right before I got it and I found a tech article on their site that said to oval out the crossmember bolt holes a very small amount in order to lower the trans.  I've since looked for this article and can't find it (I know I saw it, but for the life of me I can't find it now).  I remember thinking it was such a small amount it wouldn't make any difference.  I haven't done it because I can't find the article and am not sure I should now!!
I also never had the vibrations before the GV was installed.   
Please keep us posted with results if you do roll your punkin up!

[Just 6T9 CHGR]

Did you guys use aluminum or steel shims?

[Finn]

I put my angle finder on the harmonic balancer.

Have yet to see if it worked though haha...*fingers crossed*

[firefighter3931]

Thanks Ron.  That's a good article.  I guess my main question is-----Are the points wear I'm putting the angle finder going to give me an accurate reading?  Thanks,  Bob

Sorry Bob...i missed this question. 

I would check the angle right on the tailshaft and on the housing like you described above. 

Keep us posted on your progress. I'm wondering...did you have the driveshaft balanced ? Measured for runout ? Any play in the trans yoke ?



Ron

[RECHRGD]

Did you guys use aluminum or steel shims?

I pretty sure they're aluminum.  I'll pull them out in a couple of days and let you know.

Thanks Ron.  That's a good article.  I guess my main question is-----Are the points wear I'm putting the angle finder going to give me an accurate reading?  Thanks,  Bob

Sorry Bob...i missed this question. 

I would check the angle right on the tailshaft and on the housing like you described above. 

Keep us posted on your progress. I'm wondering...did you have the driveshaft balanced ? Measured for runout ? Any play in the trans yoke ?



Ron

Yep, it's balanced and everything else looks good.  I'll let you know how it works out.   Bob

[Just 6T9 CHGR]

Did you guys use aluminum or steel shims?

I pretty sure they're aluminum.  I'll pull them out in a couple of days and let you know.

OK cool....

[RECHRGD]

Did you guys use aluminum or steel shims?

I pretty sure they're aluminum.  I'll pull them out in a couple of days and let you know.

OK cool....

Chris----I pulled them out today and they are aluminum.  That gets me to just about a 0* angle at the pinion.  Maybe slightly down, but not much at all.  The front angle is still the 3* as before.  I'm thinking that this is what I started with, so I'll be taking it for a test drive in a week or so.  If I still have issues, I'll roll the pig up and see what happens.  Bob

[mauve66]

i'll ask some questions just to make sure the bases are covered, you may have done all of these things already...........
do you still have the GV installation book??  i can scan some pages and send them to you if you want
they have some specific tests to see if the vibration is in the engine, trans, driveshaft or rearend

several things to check,

1. disconnect driveshaft from pinion, rotate 180 degrees, if vibration worse return to original spot

2. use the scribe/clamp test to see if the driveshaft has a "heavy" side, i know you said it was balanced but...........

3. use the coast test, run up past or well into vibration range, shift to neutral, if vibration goes away stop car put trans in neutral and run through same rpm range, if vibration still there its forward of the driveshaft

4.  they also offer a diagram of where to check operating angles and what your looking for, they recomend the starter

5. remember the pinion will rotate up when under acceleration so if its up already it may be too high

[RECHRGD]

i'll ask some questions just to make sure the bases are covered, you may have done all of these things already...........
do you still have the GV installation book??  i can scan some pages and send them to you if you want
they have some specific tests to see if the vibration is in the engine, trans, driveshaft or rearend

several things to check,

1. disconnect driveshaft from pinion, rotate 180 degrees, if vibration worse return to original spot

2. use the scribe/clamp test to see if the driveshaft has a "heavy" side, i know you said it was balanced but...........

3. use the coast test, run up past or well into vibration range, shift to neutral, if vibration goes away stop car put trans in neutral and run through same rpm range, if vibration still there its forward of the driveshaft

4.  they also offer a diagram of where to check operating angles and what your looking for, they recomend the starter

5. remember the pinion will rotate up when under acceleration so if its up already it may be too high

Thanks M66!  Yes, I still have the instructions and have done all the tests.  With my headers and mini starter, there's no way for me to get a desent reading off of the starter.  My biggest mistake was not noticing that the g/v tailpiece was going to be touching the tranny support crossmember during the original installation.  Because that problem immediately reared it's ugly head, I started "adjusting" things to clear the crossmember before I could even find out if I had a pinion angle problem.  So, my upcoming test drive will now be the one I should have taken two years ago, with everything back to original except for the g/v unit. Bob

[mauve66]

hope all goes well, if not call them, they usually have a local authorized installer in bigger towns if you cant find it

[RECHRGD]

It's not fixed yet, but I think we're zeroing in on it.  Got the car on the road with the shims out of the leaf spring perches.  It still had the vibrations going on.  Had the tire balancing checked and they were in need of re-balancing.  The car was better, but still had vibrations coming in at 60mph or so and got worse with speed.  Turned the driveshaft 180*.  No change.  Set pinion angle at 3* down up front and 3* up at the pig.  A little better but still no cigar.  Had driveshaft checked and rebalanced, even though it checked out good and also double checked the length.  No change.  Went back to the driveline shop and did some further looking around underneath.  Found a lot of slop in the yoke at the tailpiece.  We called Gear Vendors, but didn't get much help.  The driveline guy tried a different yoke with a slightly smaller inner diameter and it fit fine with about 75% less play in it.  He's ordered a new yoke with the smaller diameter that will match the short length of the one supplied by GV.  The new yoke will make full contact with the GV tailshaft adaptor, unlike the GV unit.  The GV unit's splines do not start until about 3/4" into the yoke.  That leaves less than 2" of contact with the tailshaft and seems to amplify the problem.  I probably won't be able to try out the new yoke set up until mid next week.  I'll let you guys know what happens.  I really think (hope) we've found the problem here.  Bob

[RECHRGD]

Well, the tighter yoke didn't help.  This thing is driving me nuts.   The driveline guy even built a whole new driveshaft with new u-joints and everything.  We ran it up to speed on jack stands without the wheels on and still the same thing.  Vibration comes in at 65mph and goes away after about 75mph.  It makes no difference whether it's in O/D or not and will do the same thing in second gear.  It's not rpm related, it's definitely a wheel speed deal.  We called Mike at G/V and he told us to do the pipe clamp driveshaft test.  Whatever position that we tried the clamp at, it just made things worse, so the driveshaft is fine and the length is fine.  Mike then suggested trying to raise the tranny a little with washers.  We first tried just one washer per bolt and then two with no change.  We changed out the poly tranny mount for an original piece and it just got worse.  We ran it up to speed without the driveshaft installed and all was smooth, but obviously there was no load on anything.  I'm putting way too much time and money into this problem.  I'll call G/V again, but I think they're out of ideas.  Bob

[Just 6T9 CHGR]

Crap!  You are my only hope Obi-Wan!   I totally forgot about this thread with my vinyl top saga going on..

Thanks for the update good or bad Bob....keep trying!!

[RECHRGD]

Crap!  You are my only hope Obi-Wan!   I totally forgot about this thread with my vinyl top saga going on..

Thanks for the update good or bad Bob....keep trying!!

I talked to Mike at G/V again.  He wants me to try the hose clamp test on the rear of the driveshaft.  He had me do the first test up front by the tranny.  I'll try it in a couple of days and let you know the results.  I'm not going to just live with this thing.  The whole point of having the G/V unit is to be able to cruise comfortably at highway speeds and that is exactly where the vibration is.   Bob

[mauve66]

you said the vibration was the same at the same speed with or without the OD on, i assume you also ran it up in 2nd gear to see if it was just drive and GV O/D that it vibrated in

to me that means its not in the engine (whos rpm goes down or up depending on the trans gear its in)

or the trans/GV (whos shaft speed changes depending on the gear its in)

that leaves the driveshaft which would seem to be ok after they rebuilt the whole thing

or the pinion/drive axles, i would pull the axles and check the bearings and to see if the shaft is twisted and check the backlash (teeth engagement on the pinion and ring gear)

i have seen used ring and pinion that weren't a matched pair that had alot of whine and vibration due to non matched and wrong pinion depth, new gear set completely fixed that cars problem, i can only hope yours is that easy
anybody else have an idea??

[RECHRGD]

you said the vibration was the same at the same speed with or without the OD on, i assume you also ran it up in 2nd gear to see if it was just drive and GV O/D that it vibrated in

to me that means its not in the engine (whos rpm goes down or up depending on the trans gear its in)

or the trans/GV (whos shaft speed changes depending on the gear its in)

that leaves the driveshaft which would seem to be ok after they rebuilt the whole thing

or the pinion/drive axles, i would pull the axles and check the bearings and to see if the shaft is twisted and check the backlash (teeth engagement on the pinion and ring gear)

i have seen used ring and pinion that weren't a matched pair that had alot of whine and vibration due to non matched and wrong pinion depth, new gear set completely fixed that cars problem, i can only hope yours is that easy
anybody else have an idea??

Yea, did the second gear test with the same result.  I bought the rear pig from Randy's Ring and Pinion about 25K miles ago and it seems fine.  I changed wheel bearings at that time.  The axles are original, but I've never run slicks.  I have to keep going back to the fact that the car was smooth as silk before I installed the G/V unit.  Bob

[mauve66]

  We ran it up to speed without the driveshaft installed and all was smooth, but obviously there was no load on anything.  I'm putting way too much time and money into this problem.  I'll call G/V again, but I think they're out of ideas.  Bob

but the everything is still spinning at full speed so i still think its driveshaft, pinion, axle bearing related, hope this aggravation gets fixed soon

[68n70]

Hey,
For what it's worth, I've solved my problem...I took my driveshaft back out and took it to another shop and while I was there, they spun it up on their machine and you could see a slight wobble as it was not truly straight.  Also like yours, it had some slop in the rear yoke.  (This was supposed to be balanced and ok per the previous shop).  He built me a new shaft using my front yoke and a new rear and "guaranteed" I wouldn't have a vibration.  Put it in and he was right...it's completely gone!  I would have thought with the problem I had it would vibrate all the time, but mine came in when I leveled off at speed and a little on deceleration, but was fairly pronounced.
Hope that helps! 

[mauve66]

YES, i was right again, twice in 1 week, this is incrediible, woohoo, woohoo,

when your accelerating up to that point it had pressure on the yoke to take the slack out out of it then when you leveled off or decellerated the slack showed its ugly head

glad its fixed, do we get videos of smoke now?? or at least a full throttle gear change after you get used to the new shifting technique??