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Yukon 3.75 gears for Ford 9 inch....noise

42K views 127 replies 13 participants last post by  LS1-IROC 
#1 ·
Make a long story short, I built my own housing to put a Ford 9 in a 1999 Camaro SS. The car is a stick and the stock rear was making noise, so after two gear changes in the stock 7.5 and all them making noise I decided to build a 9. Everything turned out real nice except now the 9 is making noise. I started with Richmond Excels, which I know the reputation Richmonds have for making noise. Of course they made noise as low 10 mph. So, I bought a set of Yukons. I have a set in the 8.5 10 bolt in my truck and they are silent. Anyway they are 1000 times better than the Richmonds but I still have a small whine on acel and decel. I started out with the same .019 pinion shim I had with the Richmonds and the pattern was too deep. So I started to bring the pinion out. I went to .021 all I had was a .010 and a .011 to add together, back lash at .006. It still looked too deep to me but I was out of shims and the next jump I could make would be .025 and it was to far out. I loaded up the center section and took it to a local machine shop. Jimmy Mattingly’s Machine Shop. He builds pulling tractor engines and is a major Ford guy. Anyway Jimmy told me to open the backlash up and that my pinion shim looks OK. He gave me a couple more shims a .012 and a .014. This time I opened the lash up to about .008 and put the .010 and the .012 in to give me .022. It looked pretty good to me but it seemed like the drive side was staying too deep and the coast was coming out more than the drive. So I went on and tried .011 and .012 to give me .023 and it looked like the coast was too far out and the drive was good. I put it together with .022 and about .008 back lash and it has a small whine. I am thinking about just unbolting the pinion and replacing the .010 with the .011 put it back .023. I figure the lash will open up a little more but should still be in spec. looking for some opinions on where to go. I am about done with rear ends.... :pain: I only put about 5 miles on the car for a test drive. I want to fix the noise so I don’t mess the gears up.

If you would like to see the 9 I built here is a link to it on LS1 tech

http://www.ls1tech.com/forums/gears-axles/1363354-building-junkyard-9-compared-8-8-a-4.html
 
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#79 · (Edited)
lmsport said:
You can get a special spacer to run a Daytona yoke on a regular support. Randys has them for about $5

Were you using high strength Grade 8 washers?

Yes, using grade 8 washers. The more I think about it, I am really not sure what it is going on. I took another look at the support last night and the washers were lying pretty flat. Something is off, or misaligned somewhere in the pinion support or the case. My new Strange nodular iron pinion support, ARP studs, and bearings will be here today. I took a look at the OEM Ford gear that I pulled from the junk yard and ran in my housing; it has the same marks on it that the Yukon has but are a lot smaller and not as noticeable. I may try it again. I am paranoid about buying a new ring and pinion and having it gawled up.

So I have had 3 gears all in this same case and support that all show the same contact areas out on the end of the teeth. Even when I set the paatern on the drive side down towards the toe they are getting heavy contact on the heel/face under a load.

Quick Performance is about to get some bashing from me. I bought all this crap from them and they are not being very helpful. They are telling me they have sold hundreds of these case's and supports without any problems. I sent them pictures of the patterns and they questioned my gear marking compound and told me to use enamel paint. It’s pretty well common sense to see that the last pattern I had on the Yukon gear was nowhere near the marks that are now on the ring gear.
 
#81 ·
You might double check and make sure the ring gear or carrier is NOT hitting anywhere on the inside of the case. Look on the side of the pocket brg and make sure the inside of the ring gear is not scraping it.

I've also had to clearance the Aluminum case because the Hat side of the carrier was scraping.

Just something to double check.
 
#82 ·
prostreet6t9 said:
You might double check and make sure the ring gear or carrier is NOT hitting anywhere on the inside of the case. Look on the side of the pocket brg and make sure the inside of the ring gear is not scraping it.

I've also had to clearance the Aluminum case because the Hat side of the carrier was scraping.

Just something to double check.
OK, I had to grind the case around the hat area you are talking about already. The pocket bearing boss area is so big on the case that it was hitting the posi. I have plenty of clearence now. I got it together tonight, seemed like it took a while to get the shim pack right for the pinoin bearings. Pinoin bearing preload is just a shade under 15 inch pounds. When I first put it together it was 25 inch pounds but just felt way to tight. The Ford manual says 12.5 to 31.5 inch pounds. What do you think, these are brand new bearings. I ran a quick pattern with .021 pinion shim (just guessed) and lash at .006 and it looks real close to what I had last time. If this doesnt fix it then the case is bad.

What do you guys think about the way that race looked, shouldnt the wear pattern be uniform all the way around?
 
#83 ·
96lt4c4 said:
OK, I had to grind the case around the hat area you are talking about already. The pocket bearing boss area is so big on the case that it was hitting the posi. I have plenty of clearence now. I got it together tonight, seemed like it took a while to get the shim pack right for the pinoin bearings. Pinoin bearing preload is just a shade under 15 inch pounds. When I first put it together it was 25 inch pounds but just felt way to tight. The Ford manual says 12.5 to 31.5 inch pounds. What do you think, these are brand new bearings. I ran a quick pattern with .021 pinion shim (just guessed) and lash at .006 and it looks real close to what I had last time. If this doesnt fix it then the case is bad.

What do you guys think about the way that race looked, shouldnt the wear pattern be uniform all the way around?
I really couldn`t see anything from that video but we had allso nonuniform wear pattern in both carrier bearings and pinion bearings,one suggestion was that there were not enough preload or our 9+ case is bad.
 
#84 ·
TimoFinn said:
I really couldn`t see anything from that video but we had allso nonuniform wear pattern in both carrier bearings and pinion bearings,one suggestion was that there were not enough preload or our 9+ case is bad.

My carrier bearings look good as far as the wear pattern on them, its just the pinion bearings. How tight are you guys setting pinion bearing preload.
 
#86 ·
If I was going to use an aluminum support on the street, I would use less preload because of the thermal expansion difference, on new bearings around 10-15inlbs.

I have seen the unusual contact pattern on almost new races located over oil channel recesses in the race bore in certain applications, like the 8.25 and 9.25 Chrysler. I dont think it causes a problem. To me it does indicate that the race is not loaded uniformly due to the housing strength, which does not seem to be true in your application. Maybe the bore is out of round? but that seems unlikely.

Maybe you need to run your chunk in someone else's car? Or, borrow a chunk know to be quiet. Maybe the al case and your combination of suspension links is just prone to noise transfer.
 
#87 ·
lmsport said:
If I was going to use an aluminum support on the street, I would use less preload because of the thermal expansion difference, on new bearings around 10-15inlbs.

I have seen the unusual contact pattern on almost new races located over oil channel recesses in the race bore in certain applications, like the 8.25 and 9.25 Chrysler. I dont think it causes a problem. To me it does indicate that the race is not loaded uniformly due to the housing strength, which does not seem to be true in your application. Maybe the bore is out of round? but that seems unlikely.

Maybe you need to run your chunk in someone else's car? Or, borrow a chunk know to be quiet. Maybe the al case and your combination of suspension links is just prone to noise transfer.

I can understand that but for the teeth on the ring gear to galled up like they are, and where they are, indicates that something is moving or flexing under a load. Or that something is machined wrong, just enough that it doesn’t show up when I check my pattern on the bench. But as soon as it is loaded the teeth galled up. The noise I am hearing is just not right, it changes with throttle and gets louder. It is not something that you can just live with. If I were to just drive the car this way it would obviously eat up the ring gear.

I will figure it out, but I have a feeling it will be the hard way, and end up costing me more money. :rolleyes:
 
#91 ·
I just went back threw and looked at the pictures of the Motive gear pattern, look at the contact spots at the outer edge of the ring gear at the bottom of the picture.



I took apart the aluminum pinion support and this is what I found, a little sliver of aluminum came out when I pressed out one of the bearings. Also looks galled up.





Here is a video of the races



Look at the see patterns notice there is no contact on the bad area.



 
#92 ·
I could see that galled and stripped off piece of aluminum causing the race to sit funny and giving you the problem you had, pinion gear would not be held in place securely under power.

Any sign on the bottom step of that bearing race bore indicating that the piece of stripped off aluminum ended up under the race and held the race tipped a bit??
 
#93 ·
ericnova72 said:
I could see that galled and stripped off piece of aluminum causing the race to sit funny and giving you the problem you had, pinion gear would not be held in place securely under power.

Any sign on the bottom step of that bearing race bore indicating that the piece of stripped off aluminum ended up under the race and held the race tipped a bit??

I looked but could not tell, I am pretty sure I have found the source of my problem though. The reason the back race didnt galled was becasue we put the support on a hot plate and heated it up until the race dropped in. The outer bearing we just tryed to press in and it went sideways on us. Maybe we should have tryed the same route with the other bearing and it would have been fine. I can tell you one thing though if I ever build another one of these I will not be using an alluminum support.
 
#95 ·
I have been doing process of elimination. This past weekend I set up the old Ford housing with the original OEM Ford gear that came in it, 3.70. I used the new nodular iron pinion support, and the Ford racing Trac Lock that I have been using this whole time. So, now the only thing that is the same is the Trac Lock.

Something I noticed about the Yukon ring gear is that it does not fit tight on the Ford posi. I could put it on by hand. The Motive and OEM Ford gear had to be pressed on. Anyway when I took the Yukon ring gear off one of the 3 set screws that hold the 2 halves of the posi together had sheared off. The ring gear bolt holes in the posi are quite a bit bigger than the bolts, that with the ring gear not fitting tight allowed the ring gear to spin just enough that it sheared the set screws off that hold the two halves together! The hat on the posi has been machined down in a lathe, I think it has had to much taken off and is flexing under load allowing the ring gear to move away from the pinion. Here is the ford gear pattern before I ran it and what it looked like after 2 days of driving on it. It has the same marks as the Yukon gear. If anyone has any input on this let me know?
 

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#96 ·
Just talking to a guy I work with about the set screws shearing off and he thinks my ring gear bolts are bottoming out. It makes sense i will have to check when I get home.

They are the Trac Lock bolts that came in the Yukon install kit.
 
#98 ·
Well I had a few bolts that look like they may have bottomed out. But, they thread far enough into the Yukon and new Motive gear that i have that they should not bottom out. I measured and they go in further than the thickness of the posi so they should be good. The Ford gear is not drilled and tapped as deep as the others so they may have bottomed or came real close on the Ford gear. I went ahead and ground off a 1/16 inch off the bolts and ran them threw a die to straighten the threads. I am at a loss; I am running out of theory’s as to what it could be. The only thing left is the posi and maybe the housing not being straight. My axel slide right in with ease, no binding at all so I don’t see how it could be the housing. I am about ready to fix my 10 bolt and put it back in the car, maybe next winter....I dont want to ruin another ring and pinion until I know for sure what it is.
 
#100 ·
I would still suggest you try another known quiet chunk, just because you have tried so many iterations with different parts and keep getting the same results. I dont have a guess why your setup would be prone to noise transmission, but after 3 gear sets all installed with a good pattern, there is something odd going on. That is alot of noise.
 
#101 ·
lmsport said:
I would still suggest you try another known quiet chunk, just because you have tried so many iterations with different parts and keep getting the same results. I dont have a guess why your setup would be prone to noise transmission, but after 3 gear sets all installed with a good pattern, there is something odd going on. That is alot of noise.
I dont know, I am begening to wonder if it is my housing. Not being straight and causing axels to bind. We did do a lot of welding on it.
 
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