I was wondering the correct way to properly break in a new rear end. I am finally going to be making the posi swap (Eaton posi and 3:55 gears) and wondered what I need to do before putting it on the track. I have a track date coming up an a couple of months and don't want to damage anything. Please let me know if this has been covered in another post, I did a quick search and didn't turn anything up and would appreciate any info. Please advise, and thanks in advance,
From what I was told.....find room to do several figure 8's. You also do NOT want to go on any road trips right away. Alot of short trips....10 minutes or so. Helps to heat up the gears and such gradually.
gear break it Yes that all sounds good. gets the fluid all around to the bearings and stuff. the heat -up cool down is probably good too. All this will NOT hurt your rear but too is probably not nessecary either. For the street you will be fine. Posi is fine right off the bat too. Just take it easy at first to make sure everything is working properly. Listen the first time out and tune into your car. Pay more attention to the install then the break in. that will make your stuff last alot longer...lol. REALLY. Get that pattern correct and the back lash in the gm specs .005-.008. Torque your bolts correct and get the preload right on the pinion bearings. THESE are IMPORTANT. Good luck, Jim
Krazy Chris's figure 8's........ :shock: uzzled: what are you out of your tree... uzzled: :shock: ou::laugh: an old buddy or mine had a ford pickup with a 351 W. granny gear 4 spd 3.55 and a detriot locker..... I remember him sticking up his finger and proclaimed :Smarty: I've allways wanted to do this.... he put that thing in granny gear.... floored it ....slamed the clutch out and started steering :3gears: what a ride... :laugh: the tach was singing 7. 000 rpm's....well... in the process he snapped an axel :eek2: ou: it was great... two posi strips in :Brow: a bunch of figure 8 marks :TU: then a 1 wheel strip out :ball: :shock: that sucked those marks were their for over a year :laugh: what a ride :beer do what you want uzzled: but I wouldn't spin any figure 8 in any of my posi equiped cars.... :Smarty:
I'd just give it some light duty trips around town before you wail on it. Most new GM trucks come with Posi, and I never read any special break-in instructions in their owner's manual.
Currently.....yes. :laugh: The idea is to do SLOW figure eights......much like on the motorcycle road test. :TU:
i remember being told by a mechanic friend who worked for a chevy dealership when i purchased my 70 chevelle with a posi, that a few figure 8's, at low speed, were recommeded to break in the posi. worked for me. however, shortly i had a problem with the posi unit and dicovered that the wrong fluid had been poured into the pot from the factory. system was flushed & the real posi fluid (whale oil ?) was added & all was well after that. by the way, u may hear some rear end chatter from the posi when u make turns, but that is normal and should last only a short time.
