1980 trans am rear end

**gstryder** · 07-14-2016, 04:30 PM

I just had a ls dropped in my 80 TA Now the rear end seems messed up, I want to change it out to something with disc breaks maybe with 373 gears any ideas what donor would fit? Thank you all

***SMWS6TA*** · 07-15-2016, 07:14 AM

Do you know what's wrong? Slipping or broken teeth on the gear, howling?

These above are relatively simple in that depending on what the issue is what needs to be done to rebuild it.

Now if you're looking to beef it up and and a built rear end you have several options but some of your problems are going to be suspension setup, particularly working with the leaf springs.

Do you not bother with a stock 4th gen rear, they are weak and not worth building up.

Several companies out there that build rears in Ford 8.8, 9", and GM 12 bolt are the most common. Dana60 is if you're super serious about track.

Regarding the disk brake conversion, there are plenty of kits that you can convert to. IIRC you can even get the stock rear setup from a 4th gen and use on your car.

I have fab a 8.8 for mine. So far so good.

**Whamhammer** · 07-15-2016, 10:39 AM

Originally Posted by SMWS6TA

Do you know what's wrong? Slipping or broken teeth on the gear, howling?

These above are relatively simple in that depending on what the issue is what needs to be done to rebuild it.

Now if you're looking to beef it up and and a built rear end you have several options but some of your problems are going to be suspension setup, particularly working with the leaf springs.

Do you not bother with a stock 4th gen rear, they are weak and not worth building up.

Several companies out there that build rears in Ford 8.8, 9", and GM 12 bolt are the most common. Dana60 is if you're super serious about track.

Regarding the disk brake conversion, there are plenty of kits that you can convert to. IIRC you can even get the stock rear setup from a 4th gen and use on your car.

I have fab a 8.8 for mine. So far so good.

The 1980's still had a 8.5 inch rear, probably just beefing it up with some good parts, and adding on a rear disk brake conversion would probably get the job done nicely.

***SMWS6TA*** · 07-15-2016, 11:32 AM

I haven't had the "pleasure" of working on one yet. That's why I asked what was wrong with it. If it's slipping that's easy to fix, broke ring gear, again easy.

**Zapper2003** · 07-15-2016, 02:51 PM

as was stated, the 80's 10 bolt rear had an 8.5" ring gear, perfectly fine for stock ls power. gearsets for it are easy to find, as are aftermarket differentials. Right Stuff Detailing sells a very affordable disc brake conversion that's simple to install, especially since the axles have to be pulled to correct whatever the issue may be.

**gstryder** · 07-15-2016, 02:56 PM

It's making a popping sound and some grinding as well mostly when turning at low speed . It would seem to have low gears as it doesn't jump off the line but curses at 55 at really low rpm.
So I was hoping to just pop in a whole another rear end in but doesn't sound like there is a fit. I'm not a racer this is a driver and weekend fun.

***SMWS6TA*** · 07-15-2016, 03:53 PM

Sounds like bearings

**Zapper2003** · 07-15-2016, 04:45 PM

the is a bit more to it than just swapping the rear out in favor of disc brakes, too. you will also need a disc brake master cylinder and proportioning valve. to make matters worse, I have read on more than one account that the factory disc setup wasn't very good, and when compared stock for stock against drums, they're pretty much on the same playing field and neither one is better than the other.