Hi! I've setup hunderts of 8 and 9" ford gears but this 7.5 10bolt gm is giving me a hard time! I think that i can't get pinion depth correct,but not shure. Even shortend the crusher a bit last time. After two trys i'm at this point: -acceleration is very noisy -de-acc absolut quite cornering in one direction makes it a bit more quiet- in the other it gets noisier Am i right that while accelerating the pinion pulls itself closer to the ring gear? An de- acc pushes it away? I have the feeling that i need even less pinion depth,but i don't know really.. Any hints? This is a brand new set of gears.. Thanks a ton! Ollie
You're right,but this time the stuff does not show me a pattern that i can work with. Dunno why,any possible reason for this? Ollie
I think you first set the pinion depth to what ever the spec is and then use shims or threaded collars, I think the 10 bolt uses shims to set the backlash, usually .006 to .010 thou. and the use white lead or bearing grease to check the wear pattern on the ring gear....that crush sleeve just sets the bearing rolling torque
What brand gears did you use? Can you get a picture showing what the pattern looks like up? is it a 5 cut or two cut gear? What is the backlash at? There's a lot of variables that could cause it to be noisy and letting us know where everything is and a pic of the pattern would be nice.
If the pinion were to move the slightest bit one way or another under either acceleration or deceleration, something is very wrong. The amount of preload on the pinion bearings, if properly set, prevents this type of motion. Is the backlash properly set? It seems perhaps if the paste isn't giving a meaningful impression, that that would be something to check first.
sounds like a back lash is not right... i did a hand full of 7.5 when i was kid had the same resualt untill i did the back lash.. just my thoughts..
Wow,thanks for all the answers folks! As i really no nothing about GM axles: Do i set pinion depth via [FONT=Arial, Helvetica, sans-serif]inner pinion shims placed between the housing and the inner pinion-bearing cup? Well (laugh),i thought that would be adjusted with the crusher? Sorry,only know about 9". Thanks, Ollie [/FONT]
Yeah, that dimension is determined by the factory in what they once called a Gleason machine ....it is the distance from the axle center line to the pinion face......without getting that right and the bearings pre-loaded the rest is moot.
Oh,yeah and this is a bit crazy: I choosed the 7.5" out of vega because its very,very narrow.Now i have "thick gears" in 3.45 for my 2 series diff(posi,gotta keep it).And if that is'nt enough its turned down to fit the "vega/monza" smaller pinion bearing,using a S10 yoke.. gawd!headache live.. Ollie
I think the shims (pinion) go between the bearing and the pinion (where the gear is) you'll have to pull the bearing on and off
"Yeah, that dimension is determined by the factory in what they once called a Gleason machine ....it is the distance from the axle center line to the pinion face......without getting that right and the bearings pre-loaded the rest is moot." The Gleason machine you're refering to, is a Gleason Gear Testing machine. A gear & pinion are mounted in two spindles that are pre-set to the theoretical mounting distances of the gear set and run under a controled brake load and RPM to simulate operation in final ***embly. Tooth contact and backlash are checked, as is running position.The Gleason Works is the manufacturer of gear cutting, grinding, testing, heat treatment, etc machines that produce non-parallel axis gears used in the auto, aeronautical, marine and other industries worldwide. I spent 38 years working for The Gleason Works in Rochester, NY (their HQ), starting in machine build, internal production, customer training and field service. I'd be more than happy to ***ist you with your installation if you could wait until next Monday or so. I'm leaving for the Hershey swap meet in about 6-hours and won't be home until late Sunday evening. If you still want some help then, please feel free to PM me and I'll do whatever I can to ***ist you. Gleasons also has a Dealer in Stuttgart, if that would be of any help. I've been out of the company (retired) for over 7-years now, so I don't recall all of our German Dealer names, but I can find out very quickly for you. -Bob
Danas usually put the pinion depth shim between the outer race and the case, while GM rears put it between the bearing and pinion gear. I don't have pinion depth gage, so I use the old pinion shim and check the pattern, then adjust accordingly. Usually only takes on or two tries. If you can't get a pattern, then something's wrong!
Like squirrel said, if you use the original shim(s) it should get you very close (say within .005 or so.)
That's cool info about the dealers in Stuttgart.....I worked on German made transmissions quite a bit and the complicated procedures common to closed case designs would make setting up a conventional rearend seem simple by comparison.
Yep. Squirrel is right. I had a guy that did these a lot tell me to add .010 to the shims on the back of the ring gear anytime you install a new set. He was right on. It sounds like your side loading is out. remember that any change on the pinion affects the side placement of the ring.
Good news,guys! I managed to get it quiet today.Please don't laugh,here are my mistakes: I never would have thought that the pinion shim is BEHIND the bearing,as i only know 8+9" axles..Stupid me,pressed the bearing on with no shim at all...LOL.. Due to your hints,i checked that first today,and BINGO! Then i had the backlash pretty tight. All this would be ok on my Ford stuff,but here's GM.. I started with the original pinion shim,that GM put in there and that was spot on. Then i loosend the backlash very much,which brought pattern to the middle. With the added shim,was when i first got a pattern.I must be waaaay off before! By the way:I always use simple white laquer window paint,then stop the ring gear with a piece of wood until i can barley turn the pinion with a ratchet. Kinda always works for me. I bought proffesionell paste last time and it was a complete mess.Gluey like honey,the stuff..arrg.. Maybe to old?Could'nt get no real pattern with the yellow stuff.. Again stupid paint mixed with a little grease did the job..LOL! I wanna thank everybody here. Really appreciate it,very rare nowadays to get so much help!! Ollie(from Germany)
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