Hey guys. Just got a deal on a 3.27 posi unit for my 86 Z. I have been wanting to do this for a while now, and I wanted to know if it will affect anything, and if so, what will I have to change! Thanks guys!

Will

 

That depends. Are you talking about just the posi unit or the complete rear end or????

If you currently have a 9 bolt rear, the posi unit will fit, but it is a series 3 type unit and will only work with 3.23 to 4.10 gear sets. If you have 2.77 gears, they will not work with the series 3 posi unit.

If you have a 10 bolt rear, the posi unit will not work at all.

If you want to replace complete rears, yes, they are directly interchangeable.

More inforamtion on the 9 bolt is available at www.9bolt.com or www.diffsolutions.com

Miles

 

Oh, man... You didn't read his topic very well, did ya???

Yes, it will mess up your speedo. The speedo drive comes off the transmission. Bigger tires/wheels and changing gear ratios will ALL affect your speedometer. Since 3rd gens are gear driven, you may not be able to change this.

Good luck w/your decision!

 

What gears do you have now? If you have 3.23's, you'll be fine. Anything else and you'll need to change the speedo gears in the transmission. Its really simple.

 

kevin!!!


Could you please help me with changing the speedo gears in the tranny. I wanna buy the rear end because its a good deal and I proly wont put it in for a while yet. Anyway, I have the stock 2.73 non-posi setup on my Z/ I will be switching to 3.27 posi disc rear. I will have the tranny out for a rebuild when I but the new 350HO in. So if there is anyone who could help me out a bit, that would be appreciated. I think these gears will be a nice little switch from what I am running now!

Thanks all!

Will

 

Check out the tech section at http://www.sethirdgen.org/ They have an article on how to change the speedo gears in an automatic tranny. Your tranny rebuild shop should be able to handle this as well. If they cant, find a new one.