need help centering my diff?? - Lateral-g Forums

aany001 · #1 03-24-2009, 11:55 PM

This might be a stupid question but how do I know my differential is centered in my car (69 camaro). I have the DSE mini tub kit with a shortened 10 bolt and the factory perches cut off.Just would like to know where is the centre line for these diffs?? As of right know when I have the complete diff assembled with my disc brakes and 18x12 wheels installed in the car the left rear wheel is closer to the quarter lip than the right side by 3/4".From the back of the car you can really see the difference.I tried sliding the whole diff to the right approx 1/2" but I loose my gap between the left inner tire to leaf spring clearance.I have lots of space on the pass rear tire inner and outer!!! some body please shed some light on the situation!!! At least if I know that the diff is where it is supposed to be I can figure out my other clearance issues.

Thanks in advance.

Steve

chicane · #2 03-26-2009, 03:41 PM

Factory GM pinion offset from chassis centerline is... 0.500" to the passenger side.

Factory GM pinion angle, which is set at the time the perches are welded to the tubes is... +4*.

Bowtieracing · #3 03-27-2009, 03:53 AM

Quote:

Originally Posted by chicane

Factory GM pinion offset from chassis centerline is... 0.500" to the passenger side.

Factory GM pinion angle, which is set at the time the perches are welded to the tubes is... +4*.

Once again , good info

aany001 · #4 04-06-2009, 12:02 AM

thanks for the info

lewismd71 · #5 06-18-2009, 09:18 AM

Tape measure. Measure from each spring perch to pinion center. Numbers should be the same.

wedged · #6 06-18-2009, 10:13 AM

based on the chance that you've got 2 different axle lengths, determine the center of the rear by measuring the OAL , flange to flange, then divide by 2. Measuring from the pinion out will be wrong if it is offset. Someone I know did that by mistake on a pro street car and now has a gap variance from the rear tire to the 1/4.

lewismd71 · #7 06-18-2009, 12:03 PM

Quote:

Originally Posted by wedged

based on the chance that you've got 2 different axle lengths, determine the center of the rear by measuring the OAL , flange to flange, then divide by 2. Measuring from the pinion out will be wrong if it is offset. Someone I know did that by mistake on a pro street car and now has a gap variance from the rear tire to the 1/4.

axle shaft length makes no difference when centering the PINION with the vehicle. the pinion needs to be directly behind the transmission output or you will experience vibrations. if you don't believe that it doesn't matter about axle shaft length from side to side take a look at a 14 bolt full float axle. axle shafts are significantly different lengths.

measureing from the frame rail to the pinion will net you the correct placement of the PINION in relation to the car. if you are running an offset housing (such as those found in a toyota landcruiser then you will have an offset output from the t-case. those aren't used in these types of cars. why o why would you ever have a different measurement from the frame to the pinion on either side of the vehicle unless the transmission is offset. you are asking for vibrations and damage.

plain and simple, the pinion goes in the middle of the car. if you put it there and have tire clearance differences then you have a different problem...like the axle was made properly or something to do with the fender. i'm not a body man though.

wedged · #8 06-19-2009, 09:11 AM

Quote:

Originally Posted by lewismd71

axle shaft length makes no difference when centering the PINION with the vehicle. the pinion needs to be directly behind the transmission output or you will experience vibrations.

The pinion center line needs to be parallel and squared to the centerline of the transmission both vertically and horizontally. It doesn't need to be in direct alignment. In a car with suspension that moves, it would almost never be in direct alignment anyway. Trying to center the axle by measuring from the pinion center to the perch to determine the final perch location is not a good idea because there are vehicles that have the engine and differential offset from the vehicle center line. The front axle you mentioned would probably back this up, as most of them have the pinion offset a great deal. By measuing out equally from the pinion, one perch would be somewhere on the tube and the other might be out in space past the rotor/drum.