I was thinking of swapping in a 4th gen rear into my 89. I need help:

1. Is the new rear wider or narrower that the one I have and by how much.

2. Since the new rear is disc brakes and my old one is drum. do I need anything besides an AFPR?

3. Can I put my old gears (Strange 3:42) and the auburn diff in the 4th gen housing or not?

Need HELP............thanks

 

the 4th gen rear end is 4" wider.
ummm what are you gonna do with an adjustable fuel pressure regulator?
yes you can put your other gears in a 4th gen rear as long as u had a 10 bolt before

 

AH..........meant to say brake proportioning valve...

I believe it is a 10 bolt.

Will the driveshaft yolk line up OK? Can I swap in a 4th gen driveshaft (I believe they were alum.) without any mods?

 

oh ok. i really dont know anything about switching the brakes from drums but i guess that will work. yes, the driveshaft will lign up fine and one from a 4th gen will take about 10 lbs off your rotating mass if i remember correctly. it doesn't require any modifications just make sure u get one from an auto if u have an auto and a stick if u have a stick.

 

I believe all driveshafts from 82-02 V8 cars are all the same length regardless of the tranny. I took a driveshaft from an 02 t 56 car and put it in my 91 auto.

The prop valve, you need a 91-92 1LE prop valve to convert to rear disks, I got a master cyl from an LS1 car as well.

I'm also pretty sure you can interchange the carriers as long as it's a 28 spline carrier.

 

ok really dumb question...............what is a carrier (don't laugh)?

 

84 and up they are all the same length driveshaft

82 and 83 had a 3" longer shaft for the TH200c and such,


such as what my car came with from factory


i thought about a 4th gen rear for my 82 but then id have to get some really crazy backspaced wheels

so im not gonna do that

im just going to get a 3.42 or 3.73 drum rear and put aluminum drums on it and be happy with it

not going to spend more or create more hassle than i need, for a daily driver, already have way more $ into this car than it will probably ever be worth



good luck

 

The carrier is the part that the ring gear bolts to. Typically, it's either an open carrier or some sort of limited slip like a posi. You can swap your ring and pinion directly onto the fourth gens carrier. If you want to swap your 89's carrier into the fourth gen housing, you'll need to find out if you have 28 spline axles or not. The majority of 89's will have 26 spline axles. Late in the production year they were changed to 28 spline and the 1990+ all have 28 spline. There's no way you can use your third gen axles in the fourth gen so if you don't have a 28 spline carrier you either use the one in the fourth gen or buy a new one.

Since the fourth gen diff is about 2" wider on each side, your third gen wheels are going to stick out. You'll need fourth gen rims or aftermarket rims with the proper backspacing.

 

Thanks very much guys for the advice................really appreciate it