I need rearend advice!
Thread Starter
Drifting
Joined: Sep 2003
Posts: 1,927
Likes: 67
From: Saw' em off TX
I need rearend advice!
Ive got a zz4 crate with a th350 which leads to my 2:73 rearend. The 2:73 ? just isnt giving me the torque that I need. I was looking at getting a 3:73 rearend. What do you guys think, and do you know were I can get a good used rearend without digging through a junk yard? Thankyou
Thread Starter
Drifting
Joined: Sep 2003
Posts: 1,927
Likes: 67
From: Saw' em off TX
Re: I need rearend advice! (Gordonm)
I knew I was asking for a smart butt remark! Yeah I know its rare, and its really bugging the hell out of me. I can barely spin the tires. I can do about 60 in first. So does anyone know where i can get some 3:70 rearends?
Tech Contributor
Joined: Aug 1999
Posts: 15,176
Likes: 3,991
From: Connecticut, USA
Re: I need rearend advice! (03ki11er)
Do you have any swap meets in your area? Usually see vette rears for sale between $300-$500. I would suggest you become familar with the setup. Every one of the used differentials I saw at meets were in need of work. check to see if there are any cracks in the housing or carrier assembly. If they have yokes check the play,anything more then .040" and you should replace them before using it. I personally wouldn't install a used differential before going through it and changing the seals and bearings at least.
At the past Carlisle I counted 5 differentials being sold as "ready to go" that had these problems with them. You might be better off just installing new gears in your differential.
Gary
At the past Carlisle I counted 5 differentials being sold as "ready to go" that had these problems with them. You might be better off just installing new gears in your differential.
Gary
Thread Starter
Drifting
Joined: Sep 2003
Posts: 1,927
Likes: 67
From: Saw' em off TX
Re: I need rearend advice! (gtr1999)
thanks, do you know where i can get some new gears, and how hard is it to install? Or should i get somebody who knows what they are doing to install them.
Instructor
Joined: Jan 2003
Posts: 138
Likes: 1
From: Fuengirola Spain
Re: I need rearend advice! (03ki11er)
Here's a thread about where to get new rear gears:
http://forums.corvetteforum.com/zerothread?id=480513
Arto
http://forums.corvetteforum.com/zerothread?id=480513
Arto
Le Mans Master
Joined: Aug 2000
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From: Semper ubi, sub ubi
Cruise-In VI Veteran
Cruise-In VII Veteran
Re: I need rearend advice! (03ki11er)
A 2.73 rearend ratio is pretty rare in a 74, you might have a 3.08, it is really hard to tell from outside the rearend. There is usually so much slop in the drive train that the trick of marking the driveshaft and turning the rear wheels until the driveshaft makes a full turn, make it really hard to tell the difference between a 2.73 and a 3.08.
Even so a 3.08 is a pretty high ratio for good lowend performance, 3.55 or 3.70 would be pretty nice as long as you didn't do a lot of highspeed highway driving.
Another thing to look at is your Torque Convertor, a stock TC is made for smooth acceloration and doesn't best use the torque your ZZ4 makes.
A cheaper and easier swap would be to try replacing the TC to one that has a 2000-2400 stall speed. Since a ZZ4 is making 80% of its total torque by 2400 rpm, it ought to give you a real boost.
I have a 2200-2400 stall convertor on my 3.08 rearended, ZZ4, and I can spin the tires at will, heck they spin too much.
Even so a 3.08 is a pretty high ratio for good lowend performance, 3.55 or 3.70 would be pretty nice as long as you didn't do a lot of highspeed highway driving.
Another thing to look at is your Torque Convertor, a stock TC is made for smooth acceloration and doesn't best use the torque your ZZ4 makes.
A cheaper and easier swap would be to try replacing the TC to one that has a 2000-2400 stall speed. Since a ZZ4 is making 80% of its total torque by 2400 rpm, it ought to give you a real boost.
I have a 2200-2400 stall convertor on my 3.08 rearended, ZZ4, and I can spin the tires at will, heck they spin too much.
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Tech Contributor
Joined: Aug 1999
Posts: 15,176
Likes: 3,991
From: Connecticut, USA
Re: I need rearend advice! (03ki11er)
I bought my gear set from Tom's in CA. 1 562-634-8431. I researched rebuilding the differentials and got info from here. I had the tools and equipment so it wasn't too bad-but did take some time to setup correctly.
You'll need a bearing separator,good press,inch/ LB dial torque wrench,1" indicator, as well as the rebuild kit. I also have access to a machine shop so I used a surface grinder to "dial in" the shims.
If you're only going to do one car then I would send it out to Bair's or Van Steel for a rebuild. If you like to do everything yourself then read up on it and give it a shot. I have a couple more to do this Winter. I'm now setup for them and don't have to rush the work so I enjoy doing them.
Gary
You'll need a bearing separator,good press,inch/ LB dial torque wrench,1" indicator, as well as the rebuild kit. I also have access to a machine shop so I used a surface grinder to "dial in" the shims.
If you're only going to do one car then I would send it out to Bair's or Van Steel for a rebuild. If you like to do everything yourself then read up on it and give it a shot. I have a couple more to do this Winter. I'm now setup for them and don't have to rush the work so I enjoy doing them.
Gary
Drifting
Joined: Jul 2003
Posts: 1,253
Likes: 1
From: East China MI
Re: I need rearend advice! (03ki11er)
Something to consider; for "street performance" a 10 to 1 first gear ratio is a good standard. Smokehouse69 makes a big point about torque converters. Between those two things, your car should come alive. Don't forget the price you will pay on the top end.
[Modified by jpatrick636, 7:33 PM 10/12/2003]
[Modified by jpatrick636, 7:33 PM 10/12/2003]
Safety Car
Joined: Mar 2000
Posts: 3,544
Likes: 448
From: Central Pennsylvania
Re: I need rearend advice! (03ki11er)
If you do have one of those 2:73's, do yourself a favor and just put it in a corner after it's removed. Don't rebuild it. I have to believe that's worth (or will be worth) a couple of bucks. Get another rear that has the ratio of choice and put it in.