I have an opportunity to buy a Borg Warner 9 bolt rear end for my GTA. Is it worth buying? What are it's good and bad points. Any opinions are appreciated. He has the 1LE brakes to go with it, or so he says. What is a good price for these parts? Thanks

 

Good: Stronger than the 7.5" 10 bolt.

Bad: Parts are expensive or non existent.

 

you can get all new parts except for the posi cones

Got all the bearings and parts needed for a rebuild
http://www.ratechmfg.com/

 

It's plenty strong-has 4 spider pinions instead of 2 like the
10 bolt,stronger axles,7.75 ring gear.std ratios are 2.77
3.27,3.45. '88-earlier is bolt-in for '82-88 rear disc f-bod,
'89+uses pbr calipers,different discs. if you find lots of
fine metal dust in the oil-makes the oil look gray,probably
has bad posi-iron cones get gaulded and start to eat into
the carrier-i think this is probably caused by spinning the
wheels at high speed with one wheelspinning,the other with traction.I bought a 3.27 9-bolt for $300 14 yrs ago
-about a year later found the posi was bad-metal in the
oil,found an '88 3.45 recently and got it with brakes for
$400,clean oil.

 

www.9bolt.com
You can get the cones new on ebay from Australia for about $110 I think.

 

The 9 bolt BW around here is up for sale for $150. Is it easy to find different gears for thie rear? I want to put in 3:73's. I have an 89, is there a way to tell if it is the 88 & down or the 89 & up? Thanks for all the help so far guys!

 

You can also dissassemble the posi unit and get the end of the cones machined down. Then shim the posi tight again. thats what i did.

 

You will need a rear end with 3.27 gears to install the 3.73. The 3.73 won't fit the 2.77 differential.

 

Completely missed that he wanted to do that. Yes what he said except there is no such thing as 3.73 in BW world. 3.70 is what your after..basically the same thing.

 

Broke the pinion in mine.

 

So, how hard is it to find the 3:70's for the BW. It seems like this rear may be more trouble than it is worth...I mean finding parts and all. I am going to have maybe 350rwhp when I am done with my engine. Will the stock rear hold up to that? You guys are great by the way! Thanks for the help so far!

 

It will hold it. You can get the Rears from 9bolt.com or ebay. The 3.70 gears are like $170 + with the amount it will cost to get a 10 bolt as strong as a 9 bolt, is like $350+, So I went ahead and rebuilt mine. It really is pretty easy.

 

Theres this for sale in the for sale forum

https://www.thirdgen.org/forums/engi...-bolt-3-a.html

 

I got a 9 bolt 3.27 disc brake rear off of a junkyard 89 GTA for 100 bucks.You can tell the difference by the calipers.88 and down have cast iron while 89 and up have the pbr aluminum