shift points

***JC*** · 08-26-2009, 03:24 PM

I wasn't too sure where to post this question? So, I figured it's more related to the tranny than the axle...

If one swaps to a 3:73 from a 3:23 will this effect the tranny? Meaning does the shift points need adjusting? Or just leave things the way they are?

I'm not even sure if a gear swap is worth it. I don't plan on installing a 12 bolt and I don't take the car to the track. I've never taken the car to its top end and never plan too. So, a top speed of 130+ is a waste to me. I'd rather have that power in a more useful range, which is why I'm considering a gear swap.

I've been quoted $400 in labor for a gear swap which sounds to be about normal for my area.
However, I thought OEM GM gears being quoted to me at $500+ was a bit high? I've heard don't go with richmonds not sure about the other brands?

Anyway, if a gear swap means having to calibrate the tranny in adjusting the shift points then that's more money and why I'm asking this question?

**rosieredws6** · 08-26-2009, 03:30 PM

i believe you can buy oem gears from texas speed for 188, labor in dallas runs 250, not the shift points change, just the speedo, tune will corrrect the speedo then you can change shift points if your not pulling power after a certain rpm.

***JC*** · 08-26-2009, 03:32 PM

Originally Posted by rosieredws6

i believe you can buy oem gears from texas speed for 188, labor in dallas runs 250, not the shift points change, just the speedo, tune will corrrect the speedo then you can change shift points if your not pulling power after a certain rpm.

Okay but you lost me a little bit there about the speedo calibration?

Are you saying when you recalibrate the speedo for the differet sized gear it adjust the shift points for the transmission automatically?

Are OEM GM gears that expensive? I was quoted $500+ and I believe GM parts direct was saying $800+

**rosieredws6** · 08-26-2009, 03:49 PM

your shift points are already programmed in your ecu, the gears will throw your speedo off, you need a tune to correct the speedo, what i meant about the gears is with a tune they can change your shift points if your not pulling power after a certain rpm, say from 6500 to 5900 if your not pulling any more power after 5900 rpms. google texas speed and you can find the gears you need for 188.00, you might need a kit with all the new bearings and shit but thats only like an extra 80.00.

***JC*** · 08-26-2009, 04:28 PM

Originally Posted by rosieredws6

your shift points are already programmed in your ecu, the gears will throw your speedo off, you need a tune to correct the speedo, what i meant about the gears is with a tune they can change your shift points if your not pulling power after a certain rpm, say from 6500 to 5900 if your not pulling any more power after 5900 rpms. google texas speed and you can find the gears you need for 188.00, you might need a kit with all the new bearings and shit but thats only like an extra 80.00.

Thanks for the info I understand now what your saying...

By the way I checked out your recommendation and all I saw was Motive gears... I was asking about OEM GM parts not parts made to fit GM products. I was told a true GM gear is about $500 and I checked GM discount and they quoted $800. Are they really that expensive?

What's a good second choice and is a gear swap even worth the effort? I know you lose some top end but if your not driving 140+ MPH what good is it having a 3:23? Wouldn't it be of more benefit to have that power down there at a more usable range?

For arguement sake lets say a LS1/A4 with a 3:23 does 13.5 in the quarter on average. If that same car swaps to a 3:73 gear how much improvement are we looking at?

**rosieredws6** · 08-26-2009, 06:14 PM

its in the air, i think the only gears that will show drastic et times are 4.10s, very good low end. id say with 4.10s you could get a 13.0, like i said good low end.

**rosieredws6** · 08-26-2009, 06:15 PM

there is a guy on ebay also who sells gm gears, typew in the gears you want and it will say cheapest gears anywhere, some are slighlty used but i believe they are oem.

**JaycenK** · 08-27-2009, 07:23 AM

Your an auto 3.73 + street use is all you would want. If you don't do alot of racing you should be ok but don't abuse the 10 bolt. Before you do the gears you should have done a stall. One of the upgrades that will breath the most life into an auto car is a higher stall torque converter. A stall alows the engine to stay in the power insted of every time it shifts falling bellow the power curve. Car companies use low stalls for added fuel milage, the unique thing about a modern trans is they have overdrive and they have lock up converters so at slower speeds and light throtle the torque converter locks up and brings the engine rpm down to a low lwvwl and increases fuel eco. For a couple hundred bucks add a stall and trans cooler. Read up on stall speeds in the automatic section and ask a couple of questions about what others are useing and how they like them.

***JC*** · 08-29-2009, 04:25 AM

Well, from everything I've read swaping to a 3.73 gear really isn't worth it?

Thanks everyone for the advice

**Cutlass** · 08-29-2009, 05:56 AM

Originally Posted by *JC*

Well, from everything I've read swaping to a 3.73 gear really isn't worth it?

It depends on what you want from your car.
If you DD your car and don't wanna take a gas mileage hit, then no.
3.73 gear also increases your traction issues. Traction issues can slow down your 1/4 mile.
It has more leverage to put more stress on the spider gears and axle shafts. Plus the 3.73 pinion gear is smaller. All this makes the rear a little easier damage itself.

***JC*** · 08-29-2009, 09:57 AM

Originally Posted by Cutlass

It depends on what you want from your car.
If you DD your car and don't wanna take a gas mileage hit, then no.
3.73 gear also increases your traction issues. Traction issues can slow down your 1/4 mile.
It has more leverage to put more stress on the spider gears and axle shafts. Plus the 3.73 pinion gear is smaller. All this makes the rear a little easier damage itself.

Well, I hardly drive the thing... I might put on 2500 miles a year on it, if that much? However, when I do take it out it's usually to some place where it requires highway driving speeds up to 70-75 mph tops. Nevertheless, most of the time it's only around town and hardly any further than 60 miles round trip.

Anyhow everything I've read says a 3.73 gear just want make it any quicker. Besides I'm not running drag radials so there will always be traction issues in respect to street tires. Even with the 3.23 you can roast the tires from a dig. I was just curious if a 3.73 would improve one's rolling acceleration. Seems to me because it being an A4 it's sort of short on power from 35-65 mph. I have no need for top end speed I don't plan on ever going 140MPH. I also have no interest in doing a stall, at least not at this time...

With my 3.23 I'm turning 2200 RPM at 74 MPH
With a 3.73 I'd have to be turning 2550 RPM to achieve the same speed.

Plus you'd suffer the loss of gas mileage (not that means a whole lot to me) but still why give up 2 mpg for so little gain?

That's why I was wondering if the gear swap was worth it since I'm going to have the car in the shop to have the rear worked on anyway?

**Cutlass** · 08-29-2009, 10:58 AM

Well it seems to me that a 3.73 would be a good choice for you. Especially since you're not interested in a higher stall converter. Besides that fact that alot of people here say, "Don't put any money into the 7.5" 10 bolt", I'd say go for it. I've put money into a few 10 bolts and never regretted it...yet.
But you may wanna reconsider the $500 to $800 GM gearset just because there so expensive.

**lovedrvr** · 09-01-2009, 04:11 AM

dont waste your money.
i put 3.42 gears in, $500 for gears and install kit,$250 to have them installed
they whine all to hell after about a week,then the posi blew out,and $400 for a used rear(5hr swap just to get back on the road fast).
moral: i have $1200 in my rear and its still a crappy 10 bolt,i wasted half the cash it takes to just get a 12 bolt and be done with it.

get a gm 12 bolt with 3.90 gears and enjoy