njm12333

So I have an 01 z28 t56. I’m planing on upping the horsepower significantly. I have been warned and heard some horror stories about the rear ends in these cars. I know at 7.5 they are not that big or beefy. Is there a better and stronger differential I can install to keep it from blowing up or will I have to swap the whole rear end? It’s a daily driver and I like the factory gearing. I estimate to be in the low 400’s at least to the wheels after all the upgrades I have planned.

lees02WS6

iTrader: (5)

I'm surprised no one has jumped all over this question, don't worry though, you'll shortly be reading plenty. You'll have to replace the axle, which is not that big of a pain, it can be pricey though. You say this is a daily driver, unconventional opinion - unless you're putting sticky tires on and tracking the car, I wouldn't worry about it right way. That said 12 bolts are stronger, but will develop a whine. Then there are a variety of 9" options, and the dana 60. The last one is very strong, but heavy, and probably overkill for a daily.

njm12333

it is a daily driver but I do like to drive it hard sometimes. Like I said after the upgrades I’m planing it should easily be over 400whp. That’s a conservative estimate from what I have been told about what I have planned for it. That will be the extent of the power upgrades I will be doing for at least 5 years then I may go crazy with an engine swap with forced induction or beasty crate motor. I love driving it and plan to drive it a lot. I have been told many horror stories about the little 7.5 rear end blowing up. Obviously I don’t want that after all the money and time I will be putting into it. I want it solid and built to last. I love the car but I am a disabled vet so I do not have a lot of money so I need to make smart decisions on what I do. Can I swap in a new diff to beef it up or would it have to be a whole rear end swap? I like the current gearing as I’m not going to be racing it much and not worried about strip times or anything. I want to be able to drive it all over and do the power tour some time.

FirstYrLS1Z

iTrader: (4)

A different differential would still be using the puny ring & pinion gearset ( when used with a 6 speed). Automatics have their stock rears last much longer.

Ls7colorado

iTrader: (3)

If your not dumping the clutch all the time or running sticky tires they generally will last a good while even with 400WHP. BUT, if you throw some slicks on or sticky drag radials and head to the track and dumping the clutch at 4000+ rpm it might not even make it the first 60ft lol...

But for a street car that is just rolling into the throttle with street tires I would just keep note in my mind that until I can afford a 9", I probably dont need to be dropping the clutch at red lights and power shifting to 2nd every time I take off.... lol

Y2K_Frenzy

A drawback for the 9” and “12 bolt” rear ends is the likelihood of having to delete ABS and traction control if your cars have it. Even the ones who pay extra to keep ABS & TCS often times still have to delete them. After the delete the only way to get the ABS/TCS dash warning light off is to break the bulb.
So that’s something to consider. I was looking at aftermarket rears for a little while and it would’ve been pretty close to $5k once it was installed.

njm12333

it’s a driver car and I plan to keep it that way. I may take it to the strip once for fun but I’m not going to be installing any drag radials or anything like that. I will probably upgrade to some offset wheels maybe off a vette and put some fatter rears but that’s about it. I like to do some hard pulls but I don’t beat the car. I just don’t want it to explode on me. It’s is a 6 speed car as well.

LS1Formulation

iTrader: (13)

The 7.5" may as well be made out of glass in a 6-speed car. I blew mine up FOURTEEN times before I finally bit the bullet and bought a Strange S60. Do not upgrade it, it's a complete waste of money. It will break with hard driving on street tires, on the street. It's not just track excursions that kill them. For those that wonder why I rebuilt it so many times, I did all my own labor and most of the failures were ring and pinions, which my local Parts Plus kept replacing under warranty. 2 failures were posi units, one of which split clean in half. So total cost wasn't really terrible for me. I would never, ever do it again though.

My recommendation? Buy an S60 with 4 channel ABS and a Detroit Truetrac. Put 4.10 gears in it. I know you like your gearing, but our T56 transmissions have a .74 fifth and a .50 sixth gear, which means even with 4.10s you're only going to be turning 1800 RPM or so at 75MPH. Those gears absolutely wake up T56 cars. Once you upgrade, you literally would have to build an engine with 1500 HP to come close to breaking one of these axles. Yeah, it's a big expense, but if you're planning on keeping this car and will up the power eventually, do yourself a favor and beef the drivetrain first.

Furyataurus

Awhile ago you could "build" an S60 on strange's website, now you can't or I can't find it, but when I built mine for fun it came out to $4400.