well i finally got the 12 bolt in the skylark with the wilwood disc brakes. good news is it stops on a dime now, the bad is the gears are noisey as hell. i set the pinion depth to what was stamped on the face of the pinion.set the backlash and ran a pattern and it looked great. while driving you can hear it on accel mostly and maybe some on decell but it's tough to tell since it's a convertible (thats how loud it is). i figure i will take it for another ride once i get back home and then run a pattern and see what it looks like. has anyone had luck changing things around to get a better pattern and have gears quiet down? they are superior brand gears. one nice thing is stepping up from 2.78 to 3.08 made a nice difference, breaks the tires loose at 20mph.
new gears and bearings. i will have to check my pc back home for the pics. i had them on my old phone which got damaged and the pics couldn't be retrieved from it.
somethings definately funky if you can hear it on accell and decel. i guess the pics will tell the story.did you use a solid spacer or a crush sleeve?
I'd also be looking at insufficient carrier bearing preload. I made that mistake in the past and had me chasing my tail. Devon
Ok well are these used gears? because 2.78 is a 8.2 ratio... 3.08 are not NEW from this rear. Used gears are a bit harder to find a pattern. Look to the coast side for a better pattern. Used gears could be trashed already and may not be your fault. IF you can pull the carrier out after taking the caps off the preload is NOT tight enough. If you really haver to pry the hell out off it with a hammer etc. It is too tight. What shim did you use (thickness) IE. .030 .035? What is the backlash set at? .006-.010? JIm J D
They are new superior gears in a 12 bolt and I used a solid spacer. I checked the preload like the manual says and it had the proper preload.
Not sure about GM's but when i worked for Dodge the gears came marked with a + or - number and you actually did the opposite of what it was stamped. So if it was stamped -4 than you added .004 to the shims. If it was stamped +4 then you you took away .004 from the shims when setting up. It has been many yrs so i may be wrong on my description. Can you run a crush collar? I have always preferred crush collars for true preload, you just need a needle torque wrench to check the rolling torque. I helped a friend set up his D-44 in the front of his truck that used a collar, i remember that thing being like 600ftlbs of torque. The 1st time he set it up he tore the gears right out of it the test drive. He had to buy new gears and do it again, i believe he had the wrong preload on the pinion and it came loose.
Well a spacer should be fine as long as he has the proper preload. Devon wa referring to carrier preload. How hard was te carrier to get in, if his pattern is good then his pinion shim is right you would think. ---------- Post added at 08:17 PM ---------- Previous post was at 08:16 PM ---------- Any chance to get pics Paul?
I knew what devon was talking about. There is a method in the manual you do to check the carrier preload. I did have the 25-30 in.lb. of rotating force on the pinion. I am in florida until sunday so no pics yet.
here's something i just thought of. i have adjustable upper control arms with heim joints in them and i also have the trz heim joint style rear end bushings so i wouldn't have any rear suspension bind. i'm wondering if having no isolation from rear end to frame is transmitting and amplifying all rear end noise? just a thought, what do you think?
if its loud enough to make you worry i doubt that its going to be normal. you should be able to run it on jack stands and not hear it whining with your ear down there. if its transferring through the frame and staying loud enough to worry then something is up. at least from my experience..
like i said, i'm not holding my breath. a friend had them in his mustang and he had excessive noise but he thought it was because his gears were used. it's the first thing i will try though. ---------- Post added at 06:21 PM ---------- Previous post was at 06:16 PM ---------- i also talked to trz and they said they will cause this and why they don't recommend them for the street. i will run it on jack stands and see if it is still there.
ha! i actually sent these pics to my home computer from my old phone. the upper control arms are going in today and i'm going to see if that changes it.
Doers not look like the trouble as the pattern should be pretty good. Is that a MOTIVE or YUKON gear set. That what the pattern resembles. Definitely not Richmond gear pattern. Jim
well i drove it with the stock control arms in it and the noise is still there. a lot less pronounced but there. it whines on accell and howls on decell. time to change something around or just a set of richmonds. the richmonds i set up 10 years ago are quiet.
