Setting pinion preload.......

bonestock87 · Aug 22, 2008

I've got what is probably an overly simple question, but I need to get it right in my mind before I start my gear install tonight. When I read about setting the preload on the pinion gear, what I envision is that I'm supposed to tighten the pinion nut by hand (aka, a breaker bar), then once there is no front to back "play" on the pinion gear, start checking the preload with the in/lb torque wrench. And by preload what is meant is the amount of in/lb force it takes to turn the pinion gear with the torque wrench and socket on the pinion nut. Right? What I seem to keep second guessing is that once I tighten the nut that much it will already by way more than 16-29 in/lb. Can someone talk me down from the ledge on this one? I feel pretty confident I can do the overall job, but I'm the type that has to know EVERYTHING before I start or I get nervous.

Thanks!!

trinity_gt · Aug 22, 2008

bonestock87 said:
I've got what is probably an overly simple question, but I need to get it right in my mind before I start my gear install tonight. When I read about setting the preload on the pinion gear, what I envision is that I'm supposed to tighten the pinion nut by hand (aka, a breaker bar), then once there is no front to back "play" on the pinion gear, start checking the preload with the in/lb torque wrench. And by preload what is meant is the amount of in/lb force it takes to turn the pinion gear with the torque wrench and socket on the pinion nut. Right?

Exactly, with no ring-gear installed.

What I seem to keep second guessing is that once I tighten the nut that much it will already by way more than 16-29 in/lb. Can someone talk me down from the ledge on this one? I feel pretty confident I can do the overall job, but I'm the type that has to know EVERYTHING before I start or I get nervous.

Thanks!!

It will take a fair amount of torque on the pinion nut to compress the crush sleeve enough to generate the required preload. just remember you have to sneak up on it: If you tighten it too much and have too much preload torque, you can't just loosen the nut and start again...you'll have to remove the pinion and replace the crush sleeve at that point.

forum155pl · Aug 22, 2008

you need a wrench with a dial gauge on it.. once you get her tight, your supposed to put the wrench on there and turn the pinion... you want what ever your preload measurement is to match up with your dial on the wrench

make sure you use a new crush sleeve and dont overtighten the nut cuz you cant back it out without pulling it apart again and putting in another crush sleeve..

keep in mind that if you re use your pinion bearing then its going to be a tigher spec then a new bearing..

lastly.. setting up a rearend is tough stuff, i thought i could do it and it was too much. you really need a bearing press and lots of time to set her up. i tried mine and right when i drove it around the block i pulled the whole axle out and took it to a speed shop

mineralgraygt · Aug 22, 2008

just take your time you have the right idea. it easy, you need one of the inch pound torque wrenched with the hand needle on it so you can see where you at. you cant use a click type. that what i use a work after you do a few you can feel them by hand and know. if your reusing you bearings i would keep it around 15. if your putting new bearings in it would go between 20 and 30 inch pounds.

bonestock87 · Aug 23, 2008

Thanks, I really appreciate the replies and advice. Turns out a guy that I wanted to do the job for CAN do it after all, so I'm going to take the safe way out this time and pay a pro to do it. I will say that I learned a ton about how the rear end works through doing all my research and reading.

On another note, I went ahead and bought the inner and outer pinion bearings and races, along with Mobil 1 gear oil. The guy at Advance told me 2 quarts was enough. All told, it cost me another $87 for all that. Did I really need to get those new bearings? I don't mind having the new ones installed, but I couldn't help but have that "did I just blow money I didn't need to" feeling. Any comments/advice?

03ghoststang · Aug 23, 2008

i cant remember the TQ spec for the pinion nut but after its TQ down you get that needle type in./lbs TQ wrench and check the rotational TQ. If you are using the old pinion bearings it is 8-14in./lbs, with new brearings it is 16-25in./lbs.....The reason they may have told you to get a new pinion bearing is because sometimes they get damged when you remove them form the old pinion when you are getting the shim out.

Setting pinion preload.......

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Setting pinion preload.......

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