downsizing 3.42to 3.23 just for posi

[drhntr1]

could someonne explain tome what is different from 3 channel and 4 channel. if im just gonna have bolt ons on my firebird, does the gear ratio really matter that much? thinking bout getting this http://richmond.craigslist.org/pts/1611860744.html

[A fireman]

Re: downsizing 3.42to 3.23 just for posi

3 channel is referring to the ABS system. 3 channel has one speed sensor in each front wheel and only one on the rear end taking readings from right next to the ring gear. a 4CH system uses the same 2 front sensors but has one sensor at each rear wheel and no reading from the ring gear. the two can not be interchanged to my understanding without major wiring changes.
On a side note what year F-body do you have and is it a M5 or a A4?

[drhntr1]

Re: downsizing 3.42to 3.23 just for posi

2002 a4

[pace2006]

Re: downsizing 3.42to 3.23 just for posi

The one shown in that link is a 3 channel (no traction control) rear with a series 3 (3.23+) gear. If you're currently running 3.42s and don't have traction control, then that rear should work.

As fireman explained, 4 channel rears have two ABS sensor locations; one on each axle and typically incorporate traction control. 3 channel rears only have one ABS sensor that is located on top of the differential housing.

[Opontee]

Re: downsizing 3.42to 3.23 just for posi

You should be able to use a 3 channel in a 4 channel car. Just plug the hole at the top of the rear and use the axles and sensors from the car it's going in.

[T-Mill]

Re: downsizing 3.42to 3.23 just for posi

What if your ABS already doesn't work and you have a 3-channel and you wanna switch to a 4-channel?

[Mark42]

Re: downsizing 3.42to 3.23 just for posi

The rear has 120,000 miles on it. Have the posi clutch disk pack replaced before installing. They are most likely very worn at this point. They are like brakes pads, they wear out as you use them.

[Opontee]

Re: downsizing 3.42to 3.23 just for posi

What if your ABS already doesn't work and you have a 3-channel and you wanna switch to a 4-channel?

You should be able to use it, just make sure the hole at the top is selaed. I guess they both have rear disc? If not, you will have to use the brakes and axles from the car that you are putting the rear in to.

[Bird_Of_Prey]

Re: downsizing 3.42to 3.23 just for posi

You sure you don't have posi already? Most GU6 cars were optioned with G80.

[drhntr1]

Re: downsizing 3.42to 3.23 just for posi

mine doesnt have the g80 code

[Bird_Of_Prey]

Re: downsizing 3.42to 3.23 just for posi

Weird. I'd just buy a posi, 3.42 is a pretty good gear to have. 3.23 will make you slower, but improve fuel economy.

[venom3300]

Re: downsizing 3.42to 3.23 just for posi

You sure you don't have posi already? Most GU6 cars were optioned with G80.

i have GU6 and no G80 as well, it happens