I need to change my pinion angle. My rear pinion angle is nose down. Does anybody have an easy way of changing the rearend angle. I had the idea of drilling a new hole in the bracket on the rearend where the bottom trailing arm connects. Not sure if I have to do anything with the upper trailing arms?? Any help would be appreciated! Gary
How far down is it? Are you checking it with the crankshaft centerline or against the driveshaft? It should be checked with the crankshaft centerline. If you are checking it against the driveshaft it may not actually be off. Personally, I wouldn't relocate any mounting holes. If you do need to change it, adjustable upper control arms are your best bet.
Check your chassis manual, I think there are shims that will mount on the upper mounts to change the angle.
Also remember, under load the pinion climbs the ring gear and straightens out, so a bit down is okay as it'll center up under higher load. Unless you have some real solid mount bushings in the control arms.
X2 on what Randall said above. Gary, other than the visual concern about pinion angle at rest, is there some other symptom that has you determined to adjust it? Devon
Hopefully I can answer everbody's questions. I am in the process of installing a Gear vendors Overdrive. I had to lower the trans about 3/4 of an inch. I just got my new drive shaft today and I took some measurements. I have the PST poly bushings. My angle on the trans yoke is -4.5 down. My angle on the pinion yoke is +2 down. My driveshaft angle is -4 down. It looks to me that the trans to DS is fine at -.05 but the pinion to DS is a bit to much. Not sure though. Everything I have been reading, the 2 angles should be even. Please let me know what you think? Gary
The extra info helps a lot Gary, the poly bushings in the rear arms kill a lot of the normal deflection. In that case, you're right...you should try to make output shaft centerline and pinion centerline parallel, or as close to it as possible. Devon
I guess I need to find out what the best way to change the pinion angle. Gary ---------- Post added at 06:56 AM ---------- Previous post was at 05:59 AM ---------- Has anybody used UMI performance?? Looks like quality products. Gary
http://www.buickperformanceclub.com/Pinion.htm Best way is adjustable upper control arms. I use Metcos. You need to tilt the pinion yoke up 2*
I'll checkout the Metcos adjustable arms. I remeasured my angles after making sure the car was sitting in its final position. My trans angle is -5. The drive shaft is -.05 and my pinion is +.05 . Larry, I just made my test run tonite and I love the GV. Its fun to use thats for sure. I like how I can chirp the tires downshifting too. I wanted to ask you if you know what angle your tranny is at. I ended up massaging the tunnel also to try and get the angle closer to 3 degrees. I think I can tweek it up a little more, I have about 3/8 inch clearance before the top hits. Wondering what you have for angle and clearance. My header collectors hang really low. I only have 225/70/14 tires though. I drove the car about 5 miles tonite and did not feel any vibration to speak of other than a little when I had the overdrive on and was slowing down. I took on alot of challanges this spring on the car. Rebuilt the rearend from 3.08's to 3.73's, straighten out the pilot bushing issue( 13 thou out), I was driving the car for years with the clutch never adjusted correctly(throw out bearing was spinning all the time), and installing the GV unit. Just wanted to thank everybody for the help and feedback. Would not have done it without the know how and expertise everybody here has. Thanks again, Gary
Thanks Larry. I am going to tweek the trans up a little more. I will install a shim under the tranny mount.
