help setting up gears

[Fox_84]

I am setting up FRPP 373 gears and wondering if it would be best to go right back with factory shims or what? I have installed all new bearings, seals, locker, axles, everything. And what is it that I see people talking about the numbers stamped on the gears that list the gear depth requirements or something along those lines. What are all the numbers stamped on the gears? I have installed it all once and the wear pattern did not seem right. I checked it and rechecked it with the ProForm Pinion Depth tool and it comes up to be .002 thicker shim on the pinion than the factory. Should I just use the factory, because the tool and myself could make that much error. What does anyone think, what would you do? I just want to make sure this thing dont whine and I dont break gears. The wear pattern from first assembly seemed a little to much toward the heel and not as deep in the teeth on the ring as it should be. It wasnt bad, but not as desireable as everything I read. Any advise is great.

 

[rockyracoon]

well to get deeper try using that.002 shim. as far as from heel to toe,it is my understanding that is not as important as is where you are from face to flank.just get it centered face to flank and dial in a good backlash.

 

[red95gtconvert]

I went for 2.73's to 3.73' a couple of weeks ago and reused the .030" shim that was on the 2.73 pinion gear from the factory. It worked fine with no whining or funny noises coming from the rear end. Make sure to use red loctite on the pinion nut and let it cure for 24 hours before driving the car to prevent the nut from backing off on you. You will love the 3.73's, I know I do

 

[Fox_84]

Well see my factory shim is a .027 and when i put everything new back together with the old shims and set the backlash to .008 the wear pattern seems to be a little high on the teeth of the ring. I dont know if this is called face or flank but I would call it valley and peak. It is a little high, the wear pattern is running off the peak because it is too high. The only way to get the pinion to ride deeper down in the gear, more toward the valley of each tooth would be to lessen the backlash wouldnt it? I am already at lowest desired setting of .008. Any suggestions?

 

[dragnazz5.0]

there should be a number painted or stamped onto the pinion shim somewhere. its a tolerance number. say if the correct pinion depth is like 2.850" and the pinion has .03 on it that means you need to subtract .03 from the pinion shim stack. i hate those pinion depth tools. the best one out there is from rotunda and has a arbor that you put in the bearing caps and than a tool that screws down into the pinion races and all you do is put a feeler gauge in there and it tells you exactly what shim you need to put in it. but the only set back is you cant buy just the arbor and pinion tool for the 8.8 you have to buy the entire set and its like 1300 dollars

 

[rd]

I don't think Ford gears have pinion depth numbers marked on them. The Ford procedure for oem replacement gears uses a slightly different procedure with some special tools.

I have installed 2 sets with the orig shims and it worked. On the 4.10s, I did go back a couple years later and reduce the backlash.

My most recent Motive gear install had numbers, and after about 4 episodes of pinion shim trial, it got to where it came out numerically ok, and seemed to work by a pattern check.
Generally, I would put it together with out much effort in the differential shims and try to get the pinion depth set so the pattern is in the center of the ring.

Then you can play with backlash, preload and such by just varying the side shims.

 

[Jason5.0]

http://www.superstallions.com/tech/drive/gears/gears.html

try this method, worked for me on a set of 3.73's and my new 4.10's very easy to do and works perfect