82 Rear end question
Thread Starter
Advanced
Joined: Nov 2006
Posts: 64
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82 Rear end question
I´d like to change the rear gearing of my 82 Corvette, for this I first need to know what differential is installed. I know there are different ring and pinion around (different in diameter), the car is still stock.
Would prefer 3.23 gearing, cannot locate the parts. Is it worth changing to 3.08 from originally 2.72??
If anyone has experience here, let me know.
Thanks - 72-454
Would prefer 3.23 gearing, cannot locate the parts. Is it worth changing to 3.08 from originally 2.72??
If anyone has experience here, let me know.
Thanks - 72-454
Intermediate
Joined: Sep 2005
Posts: 47
Likes: 0
From: Elberta AL
I can tell you from various gear changes that going from 2.73 to 3.08 will not be worth the trouble. 3.23 will net a little gain but 3.55 would be the step where a difference would be noticed. With an 82 diff steping up the ratio is going to lead to other problems. These units are not very strong.
Safety Car
Joined: Oct 2004
Posts: 4,809
Likes: 236
From: Utah
Been there ,,done that!
I changed my gears from stock to 3.73, That was the easy part!
Most experts will recommend completely changing the diff. as the aluminum units were inherently weak. I have a zz 383 with a rebuilt 700r4. I swapped my 82 diff. for a 79 unit (iron). The change was not difficult from a mechanical perspective, but it was expensive.
Forum member GTR 1999 will have the best advice and options, PM him!
I changed my gears from stock to 3.73, That was the easy part!
Most experts will recommend completely changing the diff. as the aluminum units were inherently weak. I have a zz 383 with a rebuilt 700r4. I swapped my 82 diff. for a 79 unit (iron). The change was not difficult from a mechanical perspective, but it was expensive.
Forum member GTR 1999 will have the best advice and options, PM him!
Le Mans Master
Joined: Apr 2001
Posts: 5,000
Likes: 1
From: Minneapolis, Mn USA
Before you discount 3.07 gears with a 700R4, read this: http://www.700r4.com/faq/ratiocmp.shtml
I put in 3.07s with my rear end R&R this winter with $4 a gallon gas in mind. I was fully rebuilding the 2.87 rear anyway, so the gear was free in a sense. Car has been up on jackstands ever since so I can't comment about any improvements.
I'll be doing motor work as well and a new 700R4 with Transgo kit so I think I'll be happy overall with the performance improvements, which it needed badly.
B.
I put in 3.07s with my rear end R&R this winter with $4 a gallon gas in mind. I was fully rebuilding the 2.87 rear anyway, so the gear was free in a sense. Car has been up on jackstands ever since so I can't comment about any improvements.
I'll be doing motor work as well and a new 700R4 with Transgo kit so I think I'll be happy overall with the performance improvements, which it needed badly.
B.
Last edited by MN-Brent; Feb 27, 2009 at 09:11 PM.
Safety Car
Joined: Nov 2004
Posts: 4,359
Likes: 57
From: Mundelein Illinois
with othersHere is what I can tell you. I first changed the motor in my car to a GM Fast Burn and then changed the rear gear from 2.72 to 3.55. Accel eration was much better but RPM's were about 600 more and on the highway the motor was screaming and burning gas. I then switched back to stock.
I then installed a 5 speed and went back to the 3.55. Now this is the perfect world. Excellent accelleration and fifth gear for economy.
I would tell you not to touch the rear diff gears unless you don't care about what it costs to fill the tank. Go with a 5 speed and go for it.
In regards to the rear diff. There are not to many people that like to work on them because of the set up on them. There is no crush sleeve but alignment is done with shims. I used Blair's and they do excellent work. I'm at 300 RWHP and I have no problem with the rear end in this car. The rear end is quite strong (Street aplication) as long as you don't constantly dump the clutch at 4,000 rpm.
Learn from my mistakes. Hope this helps
Le Mans Master
Joined: Mar 2008
Posts: 5,948
Likes: 72
From: Oxford MA-----You just lost the game!!!!
I can tell you from various gear changes that going from 2.73 to 3.08 will not be worth the trouble. 3.23 will net a little gain but 3.55 would be the step where a difference would be noticed. With an 82 diff steping up the ratio is going to lead to other problems. These units are not very strong.
Just look at this guys avatar! Anyone who can twist halfshafts like that knows how to build (or buy!!) a strong rear diff! He probably knows what he's talking about.
Scott
Tech Contributor
Joined: Aug 1999
Posts: 15,124
Likes: 3,927
From: Connecticut, USA
The 80-82 diffs are not good for hp use. Yes some have run 400 hp through them but the tires were probably spinning. There has been much talk about these units and the bottom line is they were built lite weight for the cars of the period- low performance, stock cars with under 200 hp. Many have broken the bearings caps because they are weak, the design is not like the iron units and there's not much to do to beef them up. I do know a guy who will build them with a steel cap and this is better then anyone elses job out there. Me, I never work on them, won't bother as I flat out don't like them.
So you have some options
1- leave it in and see what happends
2- have a stock rebuild done, just don't add a lot of abuse to it. IMO waste of time & money
3-rebuild it with a steel cap, makes the most sense if you keep it.
4- convert to an iron unit, built to the level you want. This is the best and most expensive option. More ratios and can be built to handle over 1000 hp with the right setup.
Good luck with your choice and enjoy the car.
So you have some options
1- leave it in and see what happends
2- have a stock rebuild done, just don't add a lot of abuse to it. IMO waste of time & money
3-rebuild it with a steel cap, makes the most sense if you keep it.
4- convert to an iron unit, built to the level you want. This is the best and most expensive option. More ratios and can be built to handle over 1000 hp with the right setup.
Good luck with your choice and enjoy the car.
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Instructor
Joined: Jul 2007
Posts: 130
Likes: 3
From: Goshen IN
I was considering changing my 82(stock cf) to a 3:55, just so I would have a little more zip at low speed. Also, when I put mine into drive, it has a hard engagement /jerks. Would this soften up the feel of the hard engagement?
Burning Brakes
Joined: Feb 2006
Posts: 1,223
Likes: 4
From: Regina Saskatchewan
Personally i can't see how your going to self destruct the rear end by going from a 2.72 to a 3.08 gear. Twisted half-shafts? huh? Didn't the '80 or '81 have this same gear? You're going to be adding 13% more torque to the tires. I can't see why you wouldn't be able to feel that. Will you be able to light 'em up? No. But its a pretty cheap way of picking up 13 % more torque.
Tech Contributor
Joined: Aug 1999
Posts: 15,124
Likes: 3,927
From: Connecticut, USA
Thread Starter
Advanced
Joined: Nov 2006
Posts: 64
Likes: 0
Thanks for all those replies.
I`d like to keep it somewhat original, at least from the outside. Also don´t want the hassle adapting another rear to the frame. When it´s time and necessary I will of course. Next I also don´t want the cruise RPM go that high!
So if there are recommendations out there where I can get the right parts I would be happy to receive it. Time is no factor for my "project".
I`d like to keep it somewhat original, at least from the outside. Also don´t want the hassle adapting another rear to the frame. When it´s time and necessary I will of course. Next I also don´t want the cruise RPM go that high!
So if there are recommendations out there where I can get the right parts I would be happy to receive it. Time is no factor for my "project".
Advanced
Joined: Jan 2007
Posts: 56
Likes: 0
I did some changes
When I bought my 82 I drove it to Texas and the rear TA bearings started making noise. Thanks to this forum I found out what it was and what I had to do. Long story short, I rebuilt both front and rear suspensions and had my diff(DANA 44) rebuilt with 3.31 gears. Total 1st gear is 10.1(3.06x3.31=10.1). That is close to a turbo 350(2.52 1st gear and a 4.10 rear). I can feel the difference but it isn't dramatic. With only 200hp it wont be. Cruising is still comfortable and my milage is still great.
The 82 came with 3 inch half shafts and 1350 u joints so those wont be the week link. My dana 44 needed a new posi carrier when the shop(frontrange driveline in Denver) tore it apart.
Let me know if you have any other questions.
The 82 came with 3 inch half shafts and 1350 u joints so those wont be the week link. My dana 44 needed a new posi carrier when the shop(frontrange driveline in Denver) tore it apart.
Let me know if you have any other questions.
Advanced
Joined: Jan 2002
Posts: 77
Likes: 1
From: Stillman Valey Illinois
I´d like to change the rear gearing of my 82 Corvette, for this I first need to know what differential is installed. I know there are different ring and pinion around (different in diameter), the car is still stock.
Would prefer 3.23 gearing, cannot locate the parts. Is it worth changing to 3.08 from originally 2.72??
If anyone has experience here, let me know.
Thanks - 72-454
Would prefer 3.23 gearing, cannot locate the parts. Is it worth changing to 3.08 from originally 2.72??
If anyone has experience here, let me know.
Thanks - 72-454
