Ford 9" - gear whine noise - need help

[hotrodf1]

All,

I have successfully set up gears in a 10 bolt before, so the concept is not new, but I'm struggling to set up this 9" Ford.

I've had three gear sets in it, 4.11 4.86, 5.00, and have had issues with all of them.

The 4.86's were new from Precision, which I thought were supposed to be good gears. They were making some noise when I removed them.

THe 4.11's were used when I got them, were originally setup by a "pro" and they made noise. The 4.86's came next, and now the 4.11's are back in. And they still make noise, even after I had my ASE cert. buddy from work look at some pics of different patterns and pick the best one and then I set it up that way and installed.

The strange part of this is that the pattern on the drive and coast sides suggest different methods of correction. When the drive pattern is centered from root to crest, the coast side is way toward the crest and a bit hard on the toe.

If I get the coast side looking good, then the drive side is hard on the root of the tooth (which I was told will definetely make noise).

I have checked the pattern multiple places, and it's the same, I don't think runout is a problem.

So I can't win. Is there possibly a problem with the diff head? It's an original Ford carrier, pinion support etc., and I do have a "spare" head out back, but I hate to just try it for "fun".

Any suggestions out there woudl be much appreciated. SOrry for the long ramblings.

[hotrodf1]

Anyone have any ideas?

[Josh]

toe and heel are secondary to root and face patterns, sometimes to the point where you have to ignore toe and heel patterns. A used set of gears should have the coast side lined up priority to the drive side. Also be sure the last adjustment in the carrier preload adjusters is to tighten the left side. This will eliminate the possiblity of the backlash opening up under load.

[hotrodf1]

toe and heel are secondary to root and face patterns, sometimes to the point where you have to ignore toe and heel patterns. A used set of gears should have the coast side lined up priority to the drive side. Also be sure the last adjustment in the carrier preload adjusters is to tighten the left side. This will eliminate the possiblity of the backlash opening up under load.

Thanks for the info Josh. I had heard (from some online manual "Yukon installer or something) that having the pattern centered from root to crest was the best like you said, and also that I should pay more attention to the coast side.

It just seemed like the drive pattern didn't look very good when the coast side was optimum. I had a pretty hard line on the drive side real close to the root of the tooth, which should be a add shim pattern, but then the coast side goes away.

I guess I can try it with the pattern optimized for coast side and see what happens then. I'm getting good at taking this thing out of the car!! :hand:

If it doesn't quiet down with the pattern set up for the coast side, what's the next step?

Has anyone ever encountered a bad diff housing that was mis machined or something and just couldn't be set up properly. I work at a place that builds OTR truck axles and we see that sometimes (but they don't get to the customer usually).

[dogsbody]

Is there a set of instructions available anywhere for setting up a 9" ? I've started on mine (see 'yoke won't fit pinion' thread) but i keep stumbling across snippets of info like this that seem very important! I'm determined to have a go myself, how hard can it be ???

[Josh]

I suppose it is possible to have a bad center section. If things do not work out I would try a different center section rather than beating your head on the wall!

[hotrodf1]

Is there a set of instructions available anywhere for setting up a 9" ? I've started on mine (see 'yoke won't fit pinion' thread) but i keep stumbling across snippets of info like this that seem very important! I'm determined to have a go myself, how hard can it be ???

I did a google search with something like ford 9 inch setup or something, and that brought up a bunch of different pages and info. I woudl start there. SOrry, I didn't bookmark the pages, and can't recall what they were.

I'm running into a "special" case here, you probably won't have this kind of luck when you set yours up, especially if you get new gears.

[dogsbody]

I did a similar Google with similar results! Main problem is that they often contradict one another.
I guess there is no 'right way', You just have to pick what sounds best out of each. I was pointed to a link for Richmond gears last night which gave better info than most- http://www.richmondgear.com/01instructions.html

Good info from Josh too.
I'm realising that the little guide i've tried to compile barely scratches the surface of this!

[hotrodf1]

Thanks for the link there that helps.

Here's a great manual I found - this is the old school manual I think from Ford.

http://www.selectric.org/manuals/rearend/indexford.html

That really spells out what to do and when. I printed out all the pages for future reference. This was probably the clearest definition of what to do and when. Basically, the pinion shim moves the pattern crest to root, and backlash moves the pattern toe to heel.

I am at a point where I think I'm going to try a different carrier assy and see if the pattern is better. My carrier has a lot of passes on it from a drag car before I got it, maybe it's messed up somehow or not machined correctly from the factory (doubt it , but who knows).

[dogsbody]

Basically, the pinion shim moves the pattern crest to root, and backlash moves the pattern toe to heel.[/quote]

Again i've read that but i've also read that theres more of a crossover in the effects of each adjustment, that certainly seems to be the case with mine. The pattern seems to move in a diagonal across the tooth rather than straight up and down or side to side, makes sense when you consider the shape of the pinion!
Thanks for your link, i'll take a look at that later, it seem you can never read too much about these things!