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Is this a reasonable price for a rear end gear swap?

30K views 9 replies 8 participants last post by  against all odds 
#1 ·
I've got a 1980 Trans Am with 2.73 gear in the back(stock rear end). I'm wanting to go up to a 3.73 gear for brutal acceleration. So I called a reputable shop and they priced it at about $1,100 for the ring & pinion, installation kit, labor and everything else it will need. Now I know this is a good shop and they restore classics and build race cars. I've seen many of their cars at the local cruise in.

So would it be worth it? I've looked around the internet and most guys end up just paying around like $600-800 for everything.
 
#2 ·
i look at things like, if you can't DIY, you get what you pay for. since you did say you called a reputable shop, i would imagine they are professionals and probably do great work that will last, otherwise they would not be that reputable and prices would probably be less. you may find a cheaper place, but will they take the time to do it right, or are they only concerned about their bottom line?
 
#3 ·
I just had 3.70's put in my ford 9". I took rear assy to my speed shop & I supplied the gear set. They charged me $590 including everything else new for the swap including: 2 sets of disc pads (we had trouble matching the pads to the rotors so I got an extra set) new rotors, all bearings, races & seals, retainers, nuts, etc. and labor. This included complete set-up to include rotor and disc pad alignment. All I had to do was take the complete assy home & bolt it in. Gear sets can have a pretty good spread as far as price, but I was very pleased. Not sure how much of this info you can compare with. Bob
 
#4 ·
valtiel43 said:
I've got a 1980 Trans Am with 2.73 gear in the back(stock rear end). I'm wanting to go up to a 3.73 gear for brutal acceleration. So I called a reputable shop and they priced it at about $1,100 for the ring & pinion, installation kit, labor and everything else it will need. Now I know this is a good shop and they restore classics and build race cars. I've seen many of their cars at the local cruise in.

So would it be worth it? I've looked around the internet and most guys end up just paying around like $600-800 for everything.
did you need a different carrier?
 
#6 ·
When it comes to pricing a gear change in a rear end, you need a basic understanding of what is involved. In your case, going from a 2.73 to a 3.73 is more involved in a GM than the Ford 9" mentioned. First, there are "families" of carriers for different gear sets in the GM. Going to a different "family" in your case involves more parts to make that happen, thus a higher price. 10 years ago, I was paying $700-$800 dollars for swapping new gears in the same GM "family" so, to me, the $1000 for your swap sounds reasonable.

Trees
 
#7 ·
trees said:
When it comes to pricing a gear change in a rear end, you need a basic understanding of what is involved. In your case, going from a 2.73 to a 3.73 is more involved in a GM than the Ford 9" mentioned. First, there are "families" of carriers for different gear sets in the GM. Going to a different "family" in your case involves more parts to make that happen, thus a higher price. 10 years ago, I was paying $700-$800 dollars for swapping new gears in the same GM "family" so, to me, the $1000 for your swap sounds reasonable.

Trees
No extra parts are needed in this swap.
 
#8 ·
prostreet6t9 said:
No extra parts are needed in this swap.
Where'd you get your info? A 2 series carrier will not accept 3 or 4 series gears. You need to either change the whole carrier, or at the very least get a ring gear spacer. You definitely need more parts to swap from 2.73 to 3.73 gears.

To the original poster; if they are changing the carrier to a new posi carrier, plus ring and pinion, plus install kit, then it's a fair price indeed.
 
#9 ·
1971BB427 said:
Where'd you get your info? A 2 series carrier will not accept 3 or 4 series gears. You need to either change the whole carrier, or at the very least get a ring gear spacer. You definitely need more parts to swap from 2.73 to 3.73 gears.

To the original poster; if they are changing the carrier to a new posi carrier, plus ring and pinion, plus install kit, then it's a fair price indeed.
If its a 8.5 with a 273 carrier,the carrier split is 273 and up. Which means you can put a 273 and "UP" OR "HIGHER" NUMERICALLY on that carrier.

If its a 7.5 diff you can just get a "THICK" ring gear to do the job so NO carrier change is needed to do the swap.

Where'd I get my info? I build Driveline's and Differential's 5 days a week so I think I've done 1 or 2 chevy 10 bolts in the last 25 years.

Now if the OP's original stuff was the 8.5 in a 256 or any of the oddball hiway flyer ratio's he would need a carrier.

And yes.. If that price includes a new posi that price seems pretty good.
 
#10 ·
The other question is how long would it take for a beginner or someone who has never done this before? How much can you earn in this time period?

Example one week: Is the amount you can earn AFTER TAXES more or less than the $1100 minus parts, but don't forget tools---you'll need those, so that's an added expense.

a) Of course if you did it yourself the knowledge gained will be priceless.

b) Is this your daily driver or do you have other cars? If no, i would vote doing it yourself.

c) How the heck does a trans-am end up with 2.73 gears? i mean z-28's came with 3.42/3.73......but i digress.......


i'm on this same see-saw myself and i'm not totally sure which way to go; i would love a brand new truck, but i am still leaning towards building used one.

i don't think the $1100 totally unreasonable price-wise.
 
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