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I am replacing the diff wiylth a trutrak using stock gears. I used the pinon spacer that was on it before, probably a 0.1, ver thin. My pinion preload is 21 in/lb. Backlash is 0.9. What does this patern tell me? If I am correct I need to take some shim off of the pinion as drive is slightly closer to toe than coast. Seems weird since there is barely any shim on the pinion. Also i turned this by hand and it took almost all the marker paint off, you can barley see the patern, is that normal. But what do I know this is the first rear I am doing. Any help would be appreciated.
I just did this last year, with pics, and a few specs. Each rebuild situation will be a little different, there might be some helpful info in my thread. A year later it's doing great...
Coast side is marginally Ok-ish (at least it starting to come back together before riding off the end of the tooth), drive side says you need more pinion depth (more pinion shim, not less). But since you're reusing gears, reading the pattern gets kinda wonky.
Usually the best course when re-using gears is to check the backlash before pulling the old gears apart, leave the pinion the heck alone (like really no need to even disconnect the driveshaft , much less pull the pinion out), and reset the gears with the new locker such that the backlash is the same (or at least within 2 thousands) of the original setting.
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Coast side is marginally Ok-ish (at least it starting to come back together before riding off the end of the tooth), drive side says you need more pinion depth (more pinion shim, not less). But since you're reusing gears, reading the pattern gets kinda wonky.
Usually the best course when re-using gears is to check the backlash before pulling the old gears apart, leave the pinion the heck alone (like really no need to even disconnect the driveshaft , much less pull the pinion out), and reset the gears with the new locker such that the backlash is the same (or at least within 2 thousands) of the original setting.
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sorry, should have stated that I am rebuilding the whole thing. This started because the pinion bearing was shot and whining. So it had to come out regardless. Thanks for the insight.
sorry, should have stated that I am rebuilding the whole thing. This started because the pinion bearing was shot and whining. So it had to come out regardless. Thanks for the insight.
If the pinion bearing was “shot and whining”, then you likely have an abnormal wear pattern in the gears from the pinion moving around. You’ll probably never get a readable pattern because the gear wear pattern will mess with it ( that’s the wonky part of reusing gears).
Your options are buy another set of gears and start over, or make your best guess. If you really want to reuse your existing gears, I’d put the pinion back wherever it was (use the factory shim under the pinion bearing like you are), set the backlash on the higher side of the spec, and call it.
There is a pretty decent likelihood that you’ll have some gear noise when you’re done if you reuse what you have. A little gear noise isn’t the end of the world, and it may lessen over time as yet another wear pattern gets worn in. Just make sure to change the fluid often , especially for the first few thousand miles, and get a magnetic fill plug to help catch some of the fine particles.
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If the pinion bearing was “shot and whining”, then you likely have an abnormal wear pattern in the gears from the pinion moving around. You’ll probably never get a readable pattern because the gear wear pattern will mess with it ( that’s the wonky part of reusing gears).
Your options are buy another set of gears and start over, or make your best guess. If you really want to reuse your existing gears, I’d put the pinion back wherever it was (use the factory shim under the pinion bearing like you are), set the backlash on the higher side of the spec, and call it.
There is a pretty decent likelihood that you’ll have some gear noise when you’re done if you reuse what you have. A little gear noise isn’t the end of the world, and it may lessen over time as yet another wear pattern gets worn in. Just make sure to change the fluid often , especially for the first few thousand miles, and get a magnetic fill plug to help catch some of the fine particles.
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A worn pinion bearing (especially one worn enough to cause a sound) will cause the pinion to move around and impart an abnormal wear pattern on both the ring gear and pinion as a result . This wear pattern on the gears will likely cause gear noise when you reassemble them ( it’ll also make it damn near impossible to get a readable pattern off the gears too). You might get lucky and they’ll be noise free, or you might not.
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I had a TrueTrac installed in my Excursion's rear diff last year, the performance is great.
the installer said my Rack and Pinion gears looked fine, and he reused them.
he changed out the axle bearings "just because" they had a slight wear pattern....
those bearings are horribly expensive, but the diff is quiet, and the TrueTrac works perfect....
it pulled a loaded car trailer up a 15 degree incline in soupy, clay mud last week....
never slipped a tire, just eased up the hill like it was dry pavement.
A worn pinion bearing (especially one worn enough to cause a sound) will cause the pinion to move around and impart an abnormal wear pattern on both the ring gear and pinion as a result . This wear pattern on the gears will likely cause gear noise when you reassemble them ( it’ll also make it damn near impossible to get a readable pattern off the gears too). You might get lucky and they’ll be noise free, or you might not.
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So because of your notes I bought and put on a new Yukon ring gear and setup the new pinion with the pressed on bearing. And thank you for that as I didn't want noisey gear with all this work. I have a problem that the small bearing that slides on the shaft if the pinion after the crush sleeve (I also picked up a crush sleeve eliminator) is soo tight it won't go on easily like my old pinion. I see some people taking emery clothe and taking some material off. Is this normal?
So because of your notes I bought and put on a new Yukon ring gear and setup the new pinion with the pressed on bearing. And thank you for that as I didn't want noisey gear with all this work. I have a problem that the small bearing that slides on the shaft if the pinion after the crush sleeve (I also picked up a crush sleeve eliminator) is soo tight it won't go on easily like my old pinion. I see some people taking emery clothe and taking some material off. Is this normal?
They’re supposed to be a slight press fit, it shouldn’t just slid on with your hands. I’ve personally never had to open up the ID of a bearing, at least not one I was using for final install (so, not a setup bearing).
Normally a light tap with a dead blow mallet on the yoke with get it started enough to allow the pinion nut to be threaded on so the yoke itself would be used to press that outer pinion bearing in place.
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Yeap, or buy another identical bearing and make it a setup bearing by honing out some material in the ID like one does for the pinion nose bearing (or carrier side bearing on those axles were the shims go between the carrier and bearing)
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I have cleaned it all up with a file. Every single notch on the yoke I had to file the ends on where the nut dug into it. Or maybe I was filing out the nut shavings that adhered to it. Either way they were really on there. I then took a really big washer and ground out the center so the pinion shift could fit through. The washer was big enough to cover the hole for the pinion shaft. This was nothing would touch those splines. I will post pics if I have to take the pinion oit again to adjust for depth.
