7.5 Ring and Pinion Pattern

[superbon54]

Bonnewagon, yes a dial indicator. We improperly call them drop indicators at work because we measure the drop from one surface to another on parts we manufacture.

I used Dykem to scribe the location on the gasket surface for the magnetic base, locked in the arm and measured to the end face of the pinion gear before removal. I shimmed the new pinion at the same depth as the one I pulled out.

I replaced the original guts with a posi unit and numerically higher gears. My only monetary investment was the setup kit with bearings, shims, etc so it was one of those learn something new, not much to lose projects.

The “procedure” I used was given to me by one of those old guys that seems to know all the tricks. It may or may not have been the right way, and probably definitely not the right way on a high end or high hp car, but seemed to work well in my application.

 

[Bonnewagon]

That sounds like a great procedure. I mean it accomplishes the same thing, right? I'll have to try it some time. Of course the key is measuring BEFORE taking anything apart.

 

[superbon54]

That sounds like a great procedure. I mean it accomplishes the same thing, right? I'll have to try it some time. Of course the key is measuring BEFORE taking anything apart.

Very similar to the measure twice, cut once adage.

Measure. Measure again. Disassemble. Mock up and check specs. Disassemble and repeat as necessary. Assemble. Measure one more time. Check specs. Install into car and see what happens.

I’m sure an experienced wrench can knock it out in a few hours, but I probably had the better part of a day in the project.

 

[Rocket Powered]

Update: well guys, I solved the issue a week ago. Haven' had the time update. My inner pinion race wasn't fully seated. Whether it inched out during the several assembling/ disassembled I don't know. Very well could a been a dumba $$ attack... all makes since now. Like i said, pattern shows all. Just fine tuning now. Just a question, do you all go by factory spec on backlash or pattern ?

 

[64nailhead]

Update: well guys, I solved the issue a week ago. Haven' had the time update. My inner pinion race wasn't fully seated. Whether it inched out during the several assembling/ disassembled I don't know. Very well could a been a dumba $$ attack... all makes since now. Like i said, pattern shows all. Just fine tuning now. Just a question, do you all go by factory spec on backlash or pattern ?

Usually the wear pattern is where the marker is wiped off, but you managed to get it on the gear in the wear area ??. Whatever, that pattern looks a lot better. Really glad you took the time to recheck your work. That race not being installed correctly would've wrecked the gear set in short order and lead to a pile of disappointment .

 

[Rocket Powered]

Usually the wear pattern is where the marker is wiped off, but you managed to get it on the gear in the wear area ??. Whatever, that pattern looks a lot better. Really glad you took the time to recheck your work. That race not being installed correctly would've wrecked the gear set in short order and lead to a pile of disappointment .

I had painted a few teeth before the teeth in the pic. In the pic,the yellow, is where the teeth meshed. I had totally cleaned 5 or so teeth to see exactly where contact was made. Too much $ to just throw it together and hope for the best. Gotta be done right

 

[Bonnewagon]

So Steve nailed it- bearing race not seated. The yellow is where the teeth made contact? If so then- much better. New gears? Use factory new gears specs. Congrats!!

 

[pontiacgp]

So Steve nailed it- bearing race not seated. The yellow is where the teeth made contact? If so then- much better. New gears? Use factory new gears specs. Congrats!!

the jury is still out on that......

 

[olds307 and 403]

Glad you found it, looks a lot better. I personally like the solid pinion spacer for the 7.5", supposed to help strengthen our junk rear. I measured the factory depth before I pulled the 2.56 gears and went to used 3.42 gears. I only had to do it twice due to spider gears exploding after I broke the Powertrax No Slip with Slicks at the track and went back to open spider gears. The Trutrac is good choice behind any sort of power eliminating the tiny posi spider gears.

 

[Rocket Powered]

So Steve nailed it- bearing race not seated. The yellow is where the teeth made contact? If so then- much better. New gears? Use factory new gears specs. Congrats!!

Yup, yellow where the teeth contacted. Also yup, new gears. 373's. New everything other than the housing.