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Any thoughts? Looks damn close for my initial pinion depth adjustment. 3.90s. Backlash at .009" and .035" pinion shim. Pinion preload is at 13 in/lb without seal installed. Axles were installed and parking brake was partially engaged when spinning the carrier over.
Should also be noted that these gears are very slightly used.
I spun it over by the pinion nut with a 1/2" ratchet and axle nut socket. The axles were installed and the parking brake was partially engaged while turning.
Looks good. I wouldn't mess with it any further. You would probably end up worse.
I recall reading last night a past post where sofakingdom stated that on a used gearset, the best bet is to adjust by the coast side. If that holds true, I'd say this is about as good as it gets and I am inclined to agree that any further tampering will have me chasing my tail.
You're supposed to load the pinion flange and turn the carrier with an axle to read the pattern. If you decreased the backlash from .009 to .005, that's too tight.
You're supposed to load the pinion flange and turn the carrier with an axle to read the pattern. If you decreased the backlash from .009 to .005, that's too tight.
It's actually 006 to 007. The last backlash was on the ragged edge of .0105. I fibbed about it slightly because I knew it needed to be tightened up and didn't want to give people too many variables to argue over.
Last edited by FireDemonSiC; Apr 19, 2020 at 08:26 PM.
I've read so many different ways to get a marking it's sick. You gotta turn the ring gear, you gotta turn the pinion, spin the axle, tap the diff 4 times with a 5oz hammer, click your heals 3 times and walla.
I've also seen MANY different back lash specs. From .008 to .011, from .011 to .016. And thats both new and used. Preload pinion from 10 to 15 and 11 to 20. All from reputable books. Just saw another from reading a guy who put a 9" in. He had a pic of the specs and under the 9" specs was for the 8.8. I'm building a 8.8 and the specs that came with my gear set are way different from them.
have no idea why they are so different. Makes a guy wonder.
I was doing to say, put 5 more behind the pinion. Looks great now.
That pattern looks to me like the pinion is too deep (too much shim). Although I must admit I've never been very good at "patterns". Your comment about all the different instructions for creating it is part of the reason why.
Stock pinon shims are virtually always .035". Every single GM rear of this general type I've ever taken apart had a .035" in it from the factory. Almost makes me wonder why they bothered with a shim at all... I would say "all" but there might be one out there somewhere that's something else that I haven't seen. Every rear I've ever built, that's what ended up going back into it. That was with stock-replacement type gears though; Precision, Dana, US Gear, Motive, a few other brands of that same sort no doubt that I can't recall. The Richmond drag-race gears are different from that; if you intend to drive this on the street, I hope that's not what you have there.
If you have a .036" handy, that's what I'd put in. I'd also open up the backlash a little bit; maybe to .009" - .010". Remember, gears GROW when they get hot, and backlash GOES AWAY; I think we all know what happens when 2 pieces of metal try to occupy the same volume, and we don't like it. Gears heat up in actual load usage; the heavier the load, and the higher the speed, the more they heat up. Like so many other things (piston ring gap comes to mind), there's no such thing as achieving a "perfect" number; no matter what you set it to, it's always going to be some amount of error off of "perfect". Your best analysis technique is to figure out (a) how much error you're willing to tolerate, and (b) which direction you want it to be in. In this case, slightly "too much" backlash (emphasis on "slightly"... let's say, .002" more or less) has negligible (if even detectable) consequences, but ANY AMOUNT "too little" leads to CERTAIN DISASTER. Which direction would you prefer to err in?
Personally I like the pinion preload a bit on the high side; 24 in-lbs with new bearings or so, without the seal. I like AS MUCH carrier preload as I can get... not enough of that AUTOMATICALLY makes any backlash setting GARBAGE. How much do you have it preloaded?
Last edited by sofakingdom; May 3, 2020 at 10:16 AM.
That pattern looks to me like the pinion is too deep (too much shim). Although I must admit I've never been very good at "patterns". Your comment about all the different instructions for creating it is part of the reason why.
Stock pinon shims are virtually always .035". Every single GM rear of this general type I've ever taken apart had a .035" in it from the factory. Almost makes me wonder why they bothered with a shim at all... I would say "all" but there might be one out there somewhere that's something else that I haven't seen. Every rear I've ever built, that's what ended up going back into it. That was with stock-replacement type gears though; Precision, Dana, US Gear, Motive, a few other brands of that same sort no doubt that I can't recall. The Richmond drag-race gears are different from that; if you intend to drive this on the street, I hope that's not what you have there.
If you have a .036" handy, that's what I'd put in. I'd also open up the backlash a little bit; maybe to .009" - .010". Remember, gears GROW when they get hot, and backlash GOES AWAY; I think we all know what happens when 2 pieces of metal try to occupy the same volume, and we don't like it. Gears heat up in actual load usage; the heavier the load, and the higher the speed, the more they heat up. Like so many other things (piston ring gap comes to mind), there's no such thing as achieving a "perfect" number; no matter what you set it to, it's always going to be some amount of error off of "perfect". Your best analysis technique is to figure out (a) how much error you're willing to tolerate, and (b) which direction you want it to be in. In this case, slightly "too much" backlash (emphasis on "slightly"... let's say, .002" more or less) has negligible (if even detectable) consequences, but ANY AMOUNT "too little" leads to CERTAIN DISASTER. Which direction would you prefer to err in?
Personally I like the pinion preload a bit on the high side; 24 in-lbs with new bearings or so, without the seal. I like AS MUCH carrier preload as I can get... not enough of that AUTOMATICALLY makes any backlash setting GARBAGE. How much do you have it preloaded?
Great info and it's kinda what I was starting to think also.
This is a 8.8 fyi, street, and pinion preload I have 18 or so.
carrier, I'm not sure but I know its tight. I'm using the same shims that were in the carrier. I know I gotta drive them in, maybe alittle less resistance than driving in a freeze plug. Maybe a little more than a little if that makes sense.
I think that looks OK but as I said, I'm not real good at interpreting those. Don't take my word for it, I'll let somebody else weigh in.
Don't "drive them in". Doesn't work. Not enough to get a really premium, factory-like job.
I try to set rears up with AT LEAST .010" of carrier preload; that is, .010" more shim than I can just "drive" in there, if that makes sense.
Use 2 large C-clamps on the carrier bearings, one on each side. Set the backlash up to where you want it; carrier shims should be at maybe .225" - 265" on each side. Add .005" to each one. Put the shims in the housing, .100" thick ones on the outside, thinner ones stacked between a pair of the .100"s. Put the outer races on them and tighten the clamps. (manual preload) You should be able to get the carrier all but about ½" of the way in with the clamps on it. Maybe more if you're really careful about how you put them on the bearings. When you take the clamps off the preload you had put on the bearings will mostly remain. If it was "easy" to put it in, take it back out, and add a few more .001"s equally to each side, until it's pretty hard but not impossible or like you're going to destroy something or whatever. Use common sense. I don't think it's possible to put "too much" on them this way.
They make a tool known as a "case spreader" for this but I don't have one; and I don't like the idea of bending the case out to do it, in any case. That might be how the factory does it but I don't know, never visited a rear axle plant. But once you realize what a "case spreader" DOES, you will use a brace / girdle cover EVERY TIME you build something you want to take some abuse... since the R&P tend to "spread" the case when heavily loaded.
I think that looks OK but as I said, I'm not real good at interpreting those. Don't take my word for it, I'll let somebody else weigh in.
Don't "drive them in". Doesn't work. Not enough to get a really premium, factory-like job.
I try to set rears up with AT LEAST .010" of carrier preload; that is, .010" more shim than I can just "drive" in there, if that makes sense.
Use 2 large C-clamps on the carrier bearings, one on each side. Set the backlash up to where you want it; carrier shims should be at maybe .225" - 265" on each side. Add .005" to each one. Put the shims in the housing, .100" thick ones on the outside, thinner ones stacked between a pair of the .100"s. Put the outer races on them and tighten the clamps. (manual preload) You should be able to get the carrier all but about ½" of the way in with the clamps on it. Maybe more if you're really careful about how you put them on the bearings. When you take the clamps off the preload you had put on the bearings will mostly remain. If it was "easy" to put it in, take it back out, and add a few more .001"s equally to each side, until it's pretty hard but not impossible or like you're going to destroy something or whatever. Use common sense. I don't think it's possible to put "too much" on them this way.
They make a tool known as a "case spreader" for this but I don't have one; and I don't like the idea of bending the case out to do it, in any case. That might be how the factory does it but I don't know, never visited a rear axle plant. But once you realize what a "case spreader" DOES, you will use a brace / girdle cover EVERY TIME you build something you want to take some abuse... since the R&P tend to "spread" the case when heavily loaded.
moved it 10 away. Corrected backlash. .009.
getting worse. I've seen vids where guys keep moving it away and it gets better. I may take all shims out and try. I can switch it out in 10 min. Wanna learn the crap out of this.
First, I apologize to the op. I for some reason thought this was my thread. Haha. What a dip tard. Must gots the Corona.
Anyways, pulled all the shims out. BL is at .005ish. Looks great eh?? Haha.
Think I may right up a thread on pinion shims, and all this jaz with nice pics so people can see what's going on when they build a rear. Really it's not difficult, just having the proper tools is key. I scored this small press for free. Came with a air over hydraulic power unit, and the seals are out in the org cylinder. So I tried using my 10ton porta power cylinder and it screwed right in. So for now that's how I'm using it. You need a bearing splitter, dial indicator, caliper and a handful of hand tools. And lots of patience.
FYI, here is the final gear pattern I ended up going with. Caps were studded and torqued to 65 ft/lbs in this photo. 041" pinion shims. See above for the pattern with 035 shims. It looked good, but not good enough. Backlash is at 006" measured at 4 different areas of the ring gear 90* apart.
Pinion preload is right at 20 in/lbs with the seal installed. Cannot tell you what the torque on the nut is although it is somewhere in the neighborhood of 250 ft/lbs. You'll have to ask my Milwaukee 2767. Red loctite too. That thing ain't never coming off.
I know the backlash especially is on the tight side of spec but I'm not worried about it. It's still within all the aftermarket specs and everything will loosen up a bit once the new bearings wear in. I'm planning on taking it easy the first hundred miles or so anyways before changing the oil and then letting her eat.
FYI, here is the final gear pattern I ended up going with. Caps were studded and torqued to 65 ft/lbs in this photo. 041" pinion shims. See above for the pattern with 035 shims. It looked good, but not good enough. Backlash is at 006" measured at 4 different areas of the ring gear 90* apart.
Pinion preload is right at 20 in/lbs with the seal installed. Cannot tell you what the torque on the nut is although it is somewhere in the neighborhood of 250 ft/lbs. You'll have to ask my Milwaukee 2767. Red loctite too. That thing ain't never coming off.
I know the backlash especially is on the tight side of spec but I'm not worried about it. It's still within all the aftermarket specs and everything will loosen up a bit once the new bearings wear in. I'm planning on taking it easy the first hundred miles or so anyways before changing the oil and then letting her eat.
That's awesome! And almost exactly how mine is setup and looks!!
pinion preload- 20"#
Pinion shim- .040
Backlash- .008
Now I gotta take it apart, clean it up and do a final install. Looking forward to this crush sleeve.
I must have run 40 different patterns in a hunt for perfection on my Mustang's 8.8. Eventually decided the very first pattern was as good as any. I tossed all the math out the window and went with my gut, and you can't begin to hear the rear end over the drone of the Flowmasters. It seems like more depends on the brand of gears, and how they were cut than the install. If you mark up the gears and the pattern is relatively centered most people seem to be happy with the result.
Not yet. I have to get my driveshaft balanced. Surprisingly my LS1 shaft held up just fine to all the abuse.
I would recommend using a solid spacer instead of a crush sleeve. Get yourself a dummy outer bearing and hone the middle out ever so lightly until it is just able to be coerced on and off the pinion shaft by hand. Once you've established proper shim thickness for the spacer, install the final bearing and seal.
I would also recommend using the yellow grease a tad more sparingly. Too much will tend to smear and hide the true pattern. Like I said I just partially engaged the parking brake to the point I had to put some grunt to spin the pinion over. I'm not concerned about whether to spin it by the ring gear or the pinion as long as there is a load present. The gears will still want to bite into each trying to overcome the restriction and establish a proper pattern.
Yup, that's how it's done using a pinion setup tool. Proform sells one for 100 bucks. I opted to do it without.
I'm happy with my results.
question for ya or someone who has some experience. So the only markings on my pinion were 838. All the research I did there shoulda been a 1. In front of that. So after measuring the head of my pinion to the bearing surfaceon the pinion, by the way, it was the same as the old pinion, it was 1.8770. So heres where I'm not sure if it's a coincidence or what, but 1.877 - .030(org shim under pinion bearing) -.010(shim I added) equals 1.837. 1 tho from the 838 on the pinion head. And that's the best pattern I could come up with.
now from what I've read, the way to measure is just like your pic shows. Any idea how those numbers seem to match? Dumb luck?
Guess it doesn't really matter as I'm done playing the game. Learned a lot, confident I can setup and dif like this. 3rd members are the same concept, yet a different type of setup for adjusting.
$$ I will take ANY luck, as long as it's not BAD luck.