Gear pattern.

[rangermidtn]

Can someone look at this pattern and tell me what you think? My backlash is at .10. I think the pinion is still to shallow. I have a .30 shim on it now.
Drive side

Coast side

Any advice would be appreciated.

 

[imp]

Which axle type is it? 8.8? Your lash is 0.100 inches?? That's pretty crazy. If you drove it like that, there would be a terrific clunk each time you let off the gas, or get on it.

Lash ought to be more on the order of 0.010, rather. Remember, lash is only half of it; location of the gears to each other is equally important. That usually involves pulling bearings, changing shims, replacing bearings, checking again.

The BEST way is to measure pinion depth as Ford outlines in Shop Manual, if you can get hold of a depth micrometer. Otherwise, it can be pretty tedious.

Check your lash, after you're satisfied with it, at several different gear positions, by turning them say, 90 degrees around. imp

 

[rangermidtn]

Which axle type is it? 8.8? Your lash is 0.100 inches?? That's pretty crazy. If you drove it like that, there would be a terrific clunk each time you let off the gas, or get on it.

Lash ought to be more on the order of 0.010, rather. Remember, lash is only half of it; location of the gears to each other is equally important. That usually involves pulling bearings, changing shims, replacing bearings, checking again.

The BEST way is to measure pinion depth as Ford outlines in Shop Manual, if you can get hold of a depth micrometer. Otherwise, it can be pretty tedious.

Check your lash, after you're satisfied with it, at several different gear positions, by turning them say, 90 degrees around. imp

I meant 0.10 backlash. I know, wish I could afford one but that's not happening, that's why I was asking if anybody thought the pinion looked shallow. The marking looks to close to the top, I was wondering if anybody agreed.

 

[Grego50]

What are you measuring with? You can get a magnetic base and a depth indicator pretty cheap off eBay.
What is the the backlash tolerance per the manual, or whatever you found online for the axle your working on?
You are right about it being shallow, real shallow.

 

[imp]

Let's make sure we understand each other, here. You have a 0.300 shim "in there" now? In where" Pinion? No way 0.300" shim is EVER going to be found in an axle assembly. Do you mean "30 thousandths" of an inch? 0.030"? That's much more believable. Put these shim thicknesses into perspective: They are installed to allow for variations in machining of the castings. A common postcard is about 0.010" thick, ten-thousandths of an inch. 3 of those, possible. 10 of them, never.

What axle, again? 8.8"? What vehicle? Year? imp

 

[rangermidtn]

I have the magnetic base, but mine is a 2004 irs, so I have the aluminum housing. So I use one of my diff cover bolt holes and mount my dial. It will screw into the hole. The backlash as a range of .008 to .012. I have .010 right now. I have a .030 thousands pinion shim, it is the one that was on the stock pinion. I was told to start with the stock one and go from there. I will add some more pinion shim to it, I thought that it looked shallow.

 

[imp]

Bringing pinion closer to ring gear will decrease lash; you already are good on lash. If you increase pinion shim, try .005", but you will likely find the ring gear location will also need to be moved: away from pinion. Ford Shop Manual uses a "master bearing" to determine initial pinion shim thickness.

The diff. carrier is mounted with test shims in the housing, to achieve correct preload, with the pinion gear REMOVED. Once the preload is correct, the total stack-up of shim thickness will REMAIN THE SAME, with equal amounts added to one side and subtracted from the other side, AFTER the pinion is placed in the housing. Do you have a case-spreading tool, or are you just prying the diff. out and hammering it back in? Are you working with used or new gears?

The example in the manual, which may not be right for your setup used 0.038" on the ring gear side, 0.050" on the pinion side, of the carrier.

The pinion shim was determined using a special tool setup with the bearings in place in the housing without the pinion gear. Pinion shims available range from 053" to .073" imp

 

[rangermidtn]

Alright how does this look? Pinion shim is .038, backlash is .012.
Drive side

Coast side

 

[Grego50]

I would back out about .003 and paint 4 teeth at 4 different locations around the ring gear, check again. Getting close.

 

[rangermidtn]

I would back out about .003 and paint 4 teeth at 4 different locations around the ring gear, check again. Getting close.

Will do, thanks.

 

[imp]

Ranger, the most important thing you can do, other than checking in 4 places around the ring, is to rotate the gears back and forth as far as you can, grasping the ring gear, and feel for any "roughness" in the gear mesh. It should feel quite smooth, no light "scraping" sound, or feel. For best results, grasp the pinion flange while doing this, to increase pressure on the teeth.

If any scraping feel is present, those gears will make noise in service, just as sure as hell is hot. The pattern you show here is acceptable according to Ford Shop Manual, and I would be willing to go with it, IF, big IF: diff bearing preload is adequate, and pinion bearing preload is adequate. I always lean towards a bit MORE lash, rather than less. Racers know this, whose axles get super-hot. Pinion length increases, and lash becomes less the hotter the gears get. With what you have, the "feel" is very important.

Let us know, please. imp

Don't cut your fingers on the ring gear, use a rag!

 

[rangermidtn]

Ranger, the most important thing you can do, other than checking in 4 places around the ring, is to rotate the gears back and forth as far as you can, grasping the ring gear, and feel for any "roughness" in the gear mesh. It should feel quite smooth, no light "scraping" sound, or feel. For best results, grasp the pinion flange while doing this, to increase pressure on the teeth.

If any scraping feel is present, those gears will make noise in service, just as sure as hell is hot. The pattern you show here is acceptable according to Ford Shop Manual, and I would be willing to go with it, IF, big IF: diff bearing preload is adequate, and pinion bearing preload is adequate. I always lean towards a bit MORE lash, rather than less. Racers know this, whose axles get super-hot. Pinion length increases, and lash becomes less the hotter the gears get. With what you have, the "feel" is very important.

Let us know, please. imp

Don't cut your fingers on the ring gear, use a rag!

That's what I am doing, I am also putting pressure on the flange. So far they very smooth and quiet. Pinion preload is at 20in/lbs right now at set up, no crush sleeve. I have a .215 carrier shim ring side, .298 non ring side. Thanks for the help.

 

[boominXplorer]

I would run that last pattern. They are new and not used gears correct?

Also like imp said. Make sure your specs are right. Pinion preload is a big one once you get the crush sleeve in there. Do your side carrier shims add up to the factory shims? (I'm assuming you have stock carrier)

 

[rangermidtn]

I would run that last pattern. They are new and not used gears correct?

Also like imp said. Make sure your specs are right. Pinion preload is a big one once you get the crush sleeve in there. Do your side carrier shims add up to the factory shims? (I'm assuming you have stock carrier)

They will after I add the .005-.006 to each side for preload.They are new Motive gears.

 

[rangermidtn]

Alright what do think of this? Backlash is .010, pinion shim is .036.
Drive

Coast

 

[imp]

If that pattern above feels smooth, no "raspy" feeling, or scraping sound, ya got a good set-up. Run it! imp

 

[rangermidtn]

If that pattern above feels smooth, no "raspy" feeling, or scraping sound, ya got a good set-up. Run it! imp

Very smooth and quiet. Thanks.