Mustang and Ford Performance Forums banner
1 - 12 of 12 Posts

·
Registered
Joined
·
47 Posts
Discussion Starter · #1 ·
I am setting up my rear end gears. I have the mechanical knowledge as far as understanding how and what needs to be done. Where my knowledge lacks is determining if a gear pattern is acceptable or not . I just haven't done very many of them. I did some research online looking at pictures and so forth but I'm undecided as far as the pattern I currently landed at. I was wondering if anyone might have any input on the gear pattern I currently have. These are new gears and new bearings with .028" pinion shim as well as .009" backlash. I have attached a pictures

Mike. .
 

Attachments

·
Registered
Joined
·
402 Posts
i am no expert and have never done it (although some day i wish to) so i don't want to say 100% for sure, but from my understanding of it that looks pretty damn good! the wear pattern looks pretty much centered. if anything it looks slightly closer to the heel than the toe.

but aren't you showing both pics of the convex (drive) side? don't you also have to be looking at the coast side?

and kudos on doing this yourself, best of luck with it
 

·
Administrator
Joined
·
9,775 Posts
Reading the wear pattern to determine ring and pinion placement for proper operation is something an experienced technician can do with relatively high success. However, the Master Housing Depth (MHD) method is much preferred for the rest of us mere mortals. If you do the wear pattern setup and miss it, the ring and pinion will howl. Once the howling begins, you deform the tooth profiles on the two gears, and they can never be assembled again to run quietly. The set up to achieve a correct pattern will vary depending on whether the gears were hobbed or milled.

In Dana Corporation speak you can visually determine this by following their guidance below;

Font Rectangle Circle Number Paper


A visual pattern setup takes time and in a production environment that extra time spent is unacceptable and unavailable. The MHD approach is used because it is a one-and-done event. That said, I am attaching three documents. One is a series of pictures of gear patterns from Dana showing how to optimize the gear placement for proper operation — if that is the way you want to proceed. The other document describes the MHD approach for virtually all modern ring and pinion alternatives. I would recommend the MHD approach. That is what I use — but that is just a personal preference.

If you choose to use the visual pattern setup be sure to read the Dana doc, confirm the manufacturing process used to produce the gears and then go for it.

If you use the MHD approach, you will need to make a 1" thick pinion depth measuring plate that will bolt on where the carrier caps go. I will also attach a drawing of the plate. Order a suitably sized block of 1" thick aluminum plate from an online metals supplier that is ground or machined flat and parallel on both sides. Take the plate and the drawing to a local machine shop and ask them to make the drawn object out of the aluminum plate you brought.

Irrespective of which install type you choose to use, place your pinion shims behind the cone half of the pinion support bearing rather than between the bearing and the pinion — it will be a much easier install. If your housing does not already have it use a small Dremel tool to cut two semi-circles facing each other in the pinion-bearing cup register that are just big enough to allow you to tap the cup out with a small punch and hammer as you adjust the shim pack thickness closing in on the correct shim pack.

When you are done, save the plate — this will not be the last time you use it.
 

Attachments

·
Registered
Joined
·
47 Posts
Discussion Starter · #7 ·
Ed,

Thank you for the pdf files. Very good information!
I am currently using the factory pinion shim which was a .028" as a starting point .I did have to adjust backlash with the new frpp gears and new differential. With the shims that were in there from factory I was only getting .005"
I have it adjusted currently to .009" backlash .
I think I'm going to wait for some more feedback on the pattern i currently have. In my opinion it doesnt look to bad but that is where my experience starts to thin. It's one of those is the pattern good enough or should I try to make it perfect worm holes if you will lol.If all else fails I will start over from scratch and use a pinion depth tool for good measure.
 

·
Registered
Joined
·
47 Posts
Discussion Starter · #9 ·
Ed,

I will give the MHD method more consideration Since I have to bring the heads to the machine shop anyway I can have them machine the plate as per your attachment ,Rather be safe than sorry !
 

·
Administrator
Joined
·
9,775 Posts
If you use the MHD method and your pinion does not have a smooth machined face at the end where you will take the measurements, you need to have the machine shop grind the pinion face just enough to clean up a smooth flat face across the rough end of the pinion face. When you look at the image below, this pinion gear manufacturer machined the pinion face flat but not necessarily smooth for setup purposes.
Audio equipment Engineering Font Auto part Metal

If you are an experienced setup tech, you can work with this. If not, it is better to have the face ground flat and smooth to get an accurate measurement. You are only looking to remove enough material to clean up across the nose of the gear — no more. If your pinion face is a rough raggedy surface, find a local machine shop with a grinding capability. Have them lightly surface the face of the pinion so you can take accurate measurements.

Remember, the MHD approach measures from the centerline of the carrier bearing bore to the machined flat bearing register on the backside of the pinion gear. Put in popcorn for numbers, and you will get a bogus setup. Put in absolute numbers, and you will be happy.
 

·
Registered
Joined
·
17 Posts
Ed,

I will give the MHD method more consideration Since I have to bring the heads to the machine shop anyway I can have them machine the plate as per your attachment ,Rather be safe than sorry !
Hey those patterns look really good and eschaider telling you about the MHD method is a pretty good start but of course you are looking around $600-700 bucks for a kit to do it that way.

Only thing is I can say is that I had a great pattern (when I tried it my first time) but what really screwed me over was one of the bearings was swollen on one end somehow and that threw everything off and couldn't figure out the issue why it was inconsistent whining despite having a good pattern and correct preload (within 25-20 inch lbs turning the pinion)
If you want it done right the first time then yes use the MHD method but if it was in my mustang or F150 I would run it. Just be easy on it for 40 miles (no highway) then inspect it.
And if no noise then for about another 100 I would take it easy going 60mph 30 minute drives at most then change the fluid again and then do whatever you want at that point.

Please post an update on the pattern for either inspection (I am curious)
 

·
Administrator
Joined
·
9,775 Posts
All you need is a dial indicator, some swivel clamps, an extension rod for the indicator, some dial calipers and some threaded rod to mount to the aluminum plate I posted the drawing for. The probable eBay cost — pretty close to $50.
 
1 - 12 of 12 Posts
Top