I swaped a 2.77 posi 9-bolt rear in my car to replace my crappy 2.73 one legged 10-bolt, but ever since when making slow turns like in a parking lot the rearend feels like its hoping and I never felt this with the 10-bolt. Could someone help me figure out what could be causing this?
also before I swaped the rear in I had a transmission shop replace the pinion seal and they refilled it with gear oil and the posi additive

 

if i remember correctly, the 9bolt doesnt need posi additive. someone correct me if im wrong. i dont remember ever putting it in mine.

 

I think theres a tag right on the axle that says it requires a special lubricant. I used some redline oil so I didnt need the extra posi additive but as far as I know your supposed to use it.

As far as the hopping goes, I think its a result of the posi unit not wanting to slip a whole lot. My old 2.77 did the same thing and would kick stones and sand if i wasnt on pavement, even without giving the car any gas.

My 3.27 seems to be the same but I only really notice the hopping if im doing a sharp turn and more so at low speeds.

 

well that makes me feel better, I was getting worried that it was going to be some big expensive problem that I can't afford right now

 

I don't have any of those symptoms in my 3.27 9 bolt.

 

posi shot? or is it still good?

 

its fine

 

If it's a posi 9 bolt then you need posi additive. The hoppinh is possibly from not having any additive or not enough of it. Did you change the oil in the rear end when you swapped it? Did you put in additive?

 

I have a 9 bolt in my car and before i put it in the only thing i changed was the diff oil, and did not put in any additive. It is still working beautifully to this day.

 

is the seal a big project to do? could i get it done in an afternoon? its basically... remove the drive shaft... remove the yoke... pull the seal....wet the new seal ... put it in... put yoke back on.. and connect driveshaft... right? also will RTV be good enough to seal the diff cover? thanx..

 

no yes yes and yes

You'll need a big pair of channel-locks to hold the yoke when you pull the nut off, or an air compressor and an impact wrench.

 

Also the pinion nut has to torqued to the correct ft/lbs or good-bye bearings.

 

Actually to do it "properly" you need an inch/pound torque wrench. The torque spec isn't actually how much torque you put on the nut, but how much torque it takes to turn the pinion. You tighten the nut little by little until the pinion bearings have that certain amount of drag (preload) and then you're done.

However, that procedure is designed to be done with no load on the pinion.....i.e. with the carrier and ring gear out of the chunk. Since you're not pulling the gears you can't "properly" set the preload anyway, so you'll just have to do it by feel. Before you take it all apart, see how hard it is to turn the pinion, and when you put it back together try to get as close to that as possible. If you accidentally go a little too tight DO NOT back off. You can't go back because the crush sleeve is already compressed and if you back off the nut you will just put slack in the bearings. That will most certainly lead to premature failure.

 

I changed my seal about a week ago. It took me about 6 hours to do it. Because of the nollegable personals that work at these auto stores they made me go on a seal mission. And the funniest thing of all is that napa told me that gm never made a 9 bolt. "i will never go to napa again". But the actuall time is about 1- 1 1/2
i am saying it will take so long because of all the set up you will have with tools, putting the car on ramps, etc... I torqued my yoke to about 23-25 ft pounds. I am saying this because on my old 10 bolt that i have sitting in my back yard i checked the torque on it and it gave me 24-25 ftp ontill the nut would move. the fastest way to take out that yoke is with a impact wrench, thats how i took mine out. I hope this helps you out. -Eric

 

thanx... sure as helll helped me out:hail: when i put the rear in i had to take off the yoke because i neede to tap out one of the wholes that was stripped...and me thinking its all straight forward....i dont look at any of this and just take it off ...and put it back on with a torque wrench.. ..people said i could have messed up the rear totally.... but alls it does is leak oil... it drives great...lol...sooo... do you guys think my prob could just be the seal? would anything else be able to leak but still keep the diff functional ??

 

I would change the front seal as soon as posible. Its pritty hard to find another posi, aither 9bolt or 10bolt. Would you rather replace the whole diff and end up spending 200+, or just spending 20 bucks. If you really dont want to replace the front seal, just raise your car like every week and put more fluid. If you are going to go that way try not to mess up the plug. Its really hard to find.

 

A reply to the earlier posts. If your Posi skips it is most likely because it has been shimmed too much if it has been rebuilt. The easiest way to tell is when you replace the seal look what company made the bearings and races. If it is not GM or BW it has probably rebuilt. You do not have to use posi additive for every rear end. It depends what oil you are using.

 

any one know the part number for the pinion seal on a 3.27 ??