I posted this in differentials but couldn't quite get a grasp on whether "normal" or not. Still working a few kinks out of the 67 and still haven't downloaded the pic's onto my computer (coming soon to you though, Joe). Kevin spent more time on the carb and timing and there isn't a flat spot to be found all de way up ta 6500 - just bangs you against the seat and doesn't let up.

Anyway, I have a Currie Big 9" 3:70 that whines quite a bit. Some say that's how they sound, some say the lash is too tight, some say I got a bad bearing. The thing is brand new and only has about 300 miles on it. Maybe it's just the downtime between driving the car, but the rearend sounds awful noisy. Springs are stock, KYB shocks, Metco adjustable uppers, solid billet lowers, Hellwig sway bar.

Any thoughts opinions appreciated. BTW, I'm running Currie's recommended Torco gear oil with the small bottle of posi additive - about 3 quarts total. No oil leaking anywhere so....

What's involved in measuring and resetting lash if necessary? If a bearing, would it be inner or outer or? Fundamentally, tight lash makes sense as causing the problem - if I understand it correctly - too small of a tooth-tooth clearance would cause one heckuva racket - lube could not adequately penetrate space, heat would be nasty, and whine would be due to bind resistance.

But for now, I'm just making it up as I go cause I really have no idea what all could cause the noise.

Best,

Does it make noise as you drive or just when you let off? If it is a whine, I would guess gear set up, any bearing sound I have herd roar. I would guess tight lash first. It would seem that a 9" would make more noise than a 10 or 12 bolt due to the amount of tooth contact but I have never had the chance to hear a new 9".

I've had several 9" units and the only (1) that whined was set-up incorrectly. Took it back and they fixed it at no charge. Otherwise you don't really hear them. This is with traction-locks, nodular and aluminum 3rd members, stock and aftermarket gears (I use US gear for the most part).

Jody

Thanks guys. I guess I can send the whole unit back to Currie, but they aren't really stepping up to fix it - we're playing the all-too-familiar "It's not our fault" game. I was afraid that such a loud whine would likely be due to incorrect setup. WHAT is it with this industry and the avoidance of responsibility? The last two years on this resto have been way more fun than not, but one thing I've been tracking is the more advertising a company does, the less likely they are to take care of problems - which is right out of Business 101.

The car's coming back to Austin tomorrow or Sat I hope, so I imagine I'll be hunting down a 12-bolt AND another new driveshaft. Unfortunately, I didn't pay real close attention when people said, "Hang onto those old parts...".

Any idea on how much abuse (whine) the differential can take before welding itself together? May take me a couple weeks to get another diff - heck I may just order a 12-bolt from Moser - I can't even remember why I went with a 9" in the first place....except the original 12 bolt was very, very loose and was going to need to be rebuilt anyway.

Thanks,

Mike

Mike, there's no reason to replace the 9" if its already in there. Ford 9" are the easiest tp adjust. Bearing side load is set by a threaded adjuster. Pinnion depth is shimed. You may get away with adding a .005 - .010 shim on the pinnion to give you just enough additional clearance. I am fairly sure you can pull the pinnion out and check the pattern on the gears without completely disassembling the rear.

THANKS!!! GRN!

I was just preparing the worst - like the situation I had with the crate motor - bad build, tolerances WAY off any reasonable spec and of course the crate supplier did not want to stand behind the product.

I'll just get the car back here and then learn all about 9"'s. Guess I'll try to find a service manual that can show me where the shims go and all that, as well as how to remove, add, replace.

As part of a special Currie was running, when I bought the assembly, they sent a special 9" center section carrier that fits into the end hold on my rolling hydraulic jack. Once the car is up on stands, you unbolt the center section, reattach it to this carrier and just roll her out. Guess Currie was running the special for a reason....

Thanks again,

Mike Hartwell

Mike,

Don't remember the exact html but there is a Ford Truck Enthusiast website that I was able to get very detailed instructions on rebuilding a 9" Ford. Try doing a search for 'Ford 9" Rear' and you should get a ton of leads. They are really easy to do. I looked for the instructions briefly this morning, but they are probably out in the garage. I downloaded the file from the web originally.

No problem and thanks again. I did a search on 9"'s and got a buncha links. I even pared it down to Currie specific and still got plenty. A little looking and I'm sure I'll find plenty of specs and illustrations...

Best,

I could not imagine Currie sending out a rear end with a bad bearing. I would pull it out asap and check back lash and pinion depth. This is a good linkhttp://www.ford-trucks.com/articles/9inch/ web page (http://www.ford-trucks.com/articles/9inch/)

I talked to my dad about it and he said pinion depth. He has not built many 9" but about 3000 10 and 12 bolt and big rig rears. It could also be a mismatched gear and pinion.

Guys:

Thanks for the advice. I've been doing research like crazy and what you've said follows exactly what I have found since I've started digging into this. I now have hard data on 4 other people (Jody not included) that have had Currie 9-inchers either fail or develop the loud whine. When taken apart, all were due to improper setup. All had less than 1000 miles and all were purchased around the same time as mine.

Even Ray Currie stands fast that there's no way it would be a bad bearing and I believe him. However, it does appear that they had someone building rearends during that time period that did not understand proper setup. Nor did their "QC" catch the problem.

After a lot of googles, I found a guy in another forum that lives right here in Austin. He had the same problem with his Currie - actually worse because he kept driving the car. Same response from Currie alos - ran him around the block, said it's the oil, it sat too long, it had a bent tube, on and on and on. Sorry to say, but I gotta put Currie right in the same grouping as mitchell - customers are to be sold to, not supported.

Once again, same as with the engine, I should have had someone do a custom build or rebuild my 12 bolt. At the time, I didn't realize there was a guy so close to my back door.

The good news is that this problem was caught early, is not expensive to fix, and there's a guy about 5 miles down the road from me that can turn it around pretty quickly. BTW, he laughed his butt off when I call him about my Currie - he says they're okay to buy turnkey - just gotta get 'em into someone like him before putting them on the road so he can set the lash and pinion correctly....follows exactly what you guys are saying from a technical standpoint.

Thanks guys, really, for all the advice. I sleep alot easier now knowing I haven't just blown another $2200 on more new non-working parts....

Geez Mike,

Maybe it's just you ;)

Just bring her on over and leave her at y house for awhile - I'll sort her out :D

Joe

hmmm this is good to know.. I been looking at different rear end vendors and looking at Currie. I guess will research it a little more before I shell out $2200+ for a rear end.

Joe - LOL - I'm just an accident lookin' for a place to happen. I just got back from talking to the guys at JD Machine out on 71 (by Hamilton Pool Road) and got the whole rundown. They have an 850hp 68 Camaro in there right now w/ a Currie - same problem - same exact problem, except his is worse because the gears have already set up and the damage is already done.

Hey, I need to become a beta tester for all the performance parts! Anything that sucks is bound to wind up in my hands first....

Anyway, hope to see you at the Y in a few weeks. Looks like as soon as I get the car back in I'll be removing the center section and takin it to JD so they can machine and/or install new shims. It stung a little, but they said I am their target market - guys that buy everything prebuilt - brings them lots of business graemlins/clonk.gif

Best,