I made a technical error by disassembling my differential without first recording the turning torque at the pinion shaft as stated in both of the shop manuals that I have. Now I am re-assembling and need to recover from my error. The GM manual says to tighten the pinion nut until the turning torque is the same as it was after installation of a new oil seal. The Haynes manual says tighten until it exceeds the original torque value by 1 to 5 ft-lbs. I’m not very concerned about this minor difference, but I have no idea what torque value I should seek. The gears and bearings have not been touched on my 56,000 mile ’71 LT-1. I just did new oils seals all around. Can anyone out there give me a reasonable torque value that I should achieve?

 

the pinion nut holds the pre load for your pinion gear. so, it has to be against the crush sleeve tight enough to support the bearings, but not so tight that the bearings give it up. initially you tighten the pinion nut until there is about 15 in/lbs of pre load with used bearings. that means that it takes 15 in/lbs of torque before the pinion can rotate. but this has to be done before the carrier is installed.
the above being said for no other reason than to just give you kind of an idea of what you are trying to replicate.
i have replaced lots o pinion seals without any trouble by simply putting some locktite on the pinion nut, then tighten the nut until there is no endplay. then, i tighten the nut on down against the crush sleeve to about the point that some pre load is there, and there is enough tension against the sleeve to keep the nut from backing off.
some people like to stake the nut on some differentials to ensure it wont come loose. myself, i dont and wouldnt recommend it.
by rear end rebuilders law, once a pinion nut has been loosend, or if a pinion is over tightend, you have to replace the crush sleeve since the tension can not be regained at the same rate and in the same spot. but, i havent had any probs, although i do see their point.

i have read that it take between 300 and 400 ft/lbs of torque to crush a sleeve. seems about right. so if you are doing this job with hand tools i do not for see you gettin it too tight. with out an impact and/or a way to hold the pinion from turning i would think it would be un do able. so, unless you really get outta hand, or you are from the planet Krypton, too tight shouldnt be a problem.

i guess to simply answer your question, which was my original intention until i started typing and it got outta hand......... throw on a little thread locker for insurance, then tighten it till your against the crush sleeve, then tighten it some more.... till it feels right..... and call it good.

 

Here you go,I'm in New Haven if you need help.
http://forums.corvetteforum.com/show....php?t=1576946

 

Hey Paul! we are practicaly neighbors!!

 

Thanks for the help guys. I got the 10 to 15 in-lbs running torque range from the diff tech at Bair's over the phone today. Good to know. That is a great photo spread of the process. I will measure the running torque before I load up the pinion, then tighten to 150 ft-lbs or so, then check the running torque again. If it rises by 10 in-lbs then I think I will be close enough. Next time I will know enough to mark the nut and measure the torque before I start. If we do this stuff long enough eventually we know what we are doing!

 

Watch the range - unless I'm installing a solid sleeve I don't go by Foot pound ranges just inch pound of rotation. You don't want to overcrush the the sleeve and overload the bearings.