GM is wrong, I have 3.29 gears.

[Canada]

I swear I have 3.29s.

 

Every piece of GM information that I have says that my Impala has 2.93 gears....LIARS! In Car and Driver's review of a 06 SS (http://www.caranddriver.com/roadtests/11028/road-test-review-2006-chevrolet-impala-ss.html) they reported 3.29 gears and shift speeds (at 6k) of 49 mph, 92 mph, and 143 mph...yes, it went to 4th...and didn't stop until 154 mph. Anywho, mine shifts at the same speeds (I haven't test 3-4 yet, although the speedo stops at 140 mph...GPS anyone?).....which means they are wrong!

 

Some of the GXPs are reporting higher shift speeds.....I think they got 2.93s.

 

Perhaps my math is flawed....but Car and Driver and I both seem to agree.

 

-235/50/18 tires

 

-4T65-E...

1st...2.92

2nd...1.56

3rd...1.00

4th...0.70

 

6k shift points (redline).....you do have to manually hold second, otherwise it short shifts by 600 rpm or so.

If I did have 2.93s, I wouldn't hit 3rd until 103 mph. It doesn't shift that high...even with torque converter slur.

 

Back to top speed, recently had a guy that worked for the state dealing with drug enforcement....he went out to Conciul Bluffs behind a new Dodge Charger patrol car (no roof light bar, in the back window)....they sat at 130 or so.....apparently all the way out from Des Monies. Could be BS, but he had the transmission DTCs to back it up. Apprently you set pressure control solenoid codes...nothing wrong with it, just the PCM threw a fit because it was at near max pressure.

[GP1138]

You work at a dealer, so I'm assuming you've checked all your RPO codes?

[Canada]

Yep...it has the RPO code for 2.93s....EVERY piece of information....parts catalog, service manuals, dealer flyer, RPO sticker, VIS build sheet...everything says it.

 

BUT...it shifts at 49 and 92 mph!!!!???!!!!!

 

And to beat down the torque converter slip guys......at 2k in 4th with the TCC on, its at 68 mph. You'd be around 76 if it had 2.93s.

[mra32]

Maybe your speedo is off?

 

<hijack>

 

On the other hand, I have a gps reciever that i plug into my laptop when I go on trips. Its great and it will actually tell my how fast im going since my speedo is about 10% off. Not to mention the directions and tracking I can get with it.

 

</hijack>

[Miko K]

Mine shifts around 50MPH in 2nd and 85-88 in 3rd at 5500RPM and 2.93's and my HUD says that, the speedo is acurate in the lower numbers, around 60-90 is says 4-5MPH more than the digital HUD and around 110 its back to acurate. So there is a 99% chance you have 2.93's.

[99RegalGS]

huh? I think with the information you gave it proves even more that he has the 3.29 gears.

[Canada]

You tires are shorter (225/60/16 verses 235/50/18)...about 2" shorter in circumference. This means all else the same (shift point and ratios) the taller tired car is going to shift higher.

[BIGBULS]

I told you you had 3.29 numb-nuts...............

 

And yes, GXP's DID get 2.93's (and a 142mph governor).

 

 

 

Also, I should point out a 97-03 GTP (which has 2.93's and shorter tires, but the SAME redline as Canada's car) will go 96mph at the 6K rev limit in 2nd.............GPS (and HUD/Speedo) verified by ME.

 

So..............92mph in 2nd with taller tires = 3.29's.

 

 

 

 

Here's an idea Canada......................go look up the part numbers for your transfer gears inside the tranny.............if they are both 35 tooth gears (NOT a 33 and a 37), then you have 3.29's.................as ALL of the new V8's have a 3.29 DIFF (but the GXP's as mentioned are geared down internally).

 

You know..............you could always get some tuning software (for the shiftpoints) and go 37/33 for internal transfer gears.............that's a 3.69 FDR right there

[BIGBULS]

http://media.gm.com/us/powertrain/en/product_services/2007/Spec%20Sheet/Transmissions/2007%20Automatics/07%204T65-E%20(M15,MD7,MN7)APP.xls

 

Ok, so suddenly it seems that ALL MN7 cars got 3.29's..............not just Impala's (so GXP's too........at least newer ones??)

 

Another inconsistancy is that I'm reasonably certain Malibu Maxx's got 3.69's............yet the above chart says 3.29.

 

Hmmmm...........

 

 

 

 

 

Edit: AH-HA!

 

http://media.gm.com/us/powertrain/en/product_services/2007/Whats%20New/07_MN7.doc

 

Go about 1/2 way down.................3 FDR's, with 3 sproket ratios = 9 AXLE ratios.

 

 

 

 

 

Anyway...............I'm still betting 3.29's

[Canada]

Crazy car, I haven't checked the parts catalog yet......but at least the VIS agrees with it having the MN7 transmission, yet it has FR2 2.93s

 

If you go to unit repair in SI, it doesn't list the LS4 under the MN7 transmission...

[Canada]

Welp, catalog shows 2.93s....but I'll bet its because of FR2.

 

I don't think I'm crazy......I swear that the 1-2 shift happens at 49-50 mph...I've done it at least 10 times in a row.

[dbtk2]

Canada, what size tires are on your car? Also what are your shiftpoints (RPM)? Based on what you posted, it sounds like the typical 2.93 geared car.

 

FWIW, my GP GT has 225/60/16 tires and 3.29 gears and it shifts 1-2 at 46mph (6450rpm) and 2-3 at 88mph (6450rpm). My 6800rpm rev limiter is around 48mph in 1st and is 93mph in 2nd. I don't remember for sure but IIRC the stock 1-2 shift was 42mph and 2-3 was 77 or 78mph.

 

The stock file from my moms '00 SSEi (2.93 gears, 235/55/17 tires) had 1-2 shift at 47mph and 2-3 at 87mph. With its DHP PCM and 5950rpm shift points it now shifts at 50mph 1-2 and 90mph 2-3. 6400rpm rev limiter comes in JUST shy of 100mph IIRC.

 

Sounds like you have 2.93's to me.

[BIGBULS]

I quote myself.................

 

Also, I should point out a 97-03 GTP (which has 2.93's and shorter tires, but the SAME redline as Canada's car) will go 96mph at the 6K rev limit in 2nd.............GPS (and HUD/Speedo) verified by ME.

 

So..............92mph in 2nd with taller tires = 3.29's.

 

 

*I* think he has 3.29's.

 

His tires BTW are 235/50R18's............taller than the GTP OR Bonneville by a bit.

 

Also, be aware that the programmed in (via DHP or other software) shiftpoints on a 65-E are not usually where they actually SHIFT............there is almost always some lag (especially for 1-2).

 

 

Throw in the fact that modded cars usually slip the rpm a little more due to the etra power and we now see why your Bonne shifts where it does..........

 

 

On that note....one other point: a STOCK GPGT (with 3.29's and 225/60R16's) WILL go 87-89mph in 2nd gear before the 6K (5950...whatever ) rev limiter cuts. I've done it at the drag strip (in 2 seperate cars)...........usually a totally stock car will know it has a good run because it'll hit the 2nd gear limiter just as it goes through the traps (trapping at 88ish with hopefully a 15.7 or so under it's belt).

[dbtk2]

I quote myself.................

 

Also, I should point out a 97-03 GTP (which has 2.93's and shorter tires, but the SAME redline as Canada's car) will go 96mph at the 6K rev limit in 2nd.............GPS (and HUD/Speedo) verified by ME.

 

So..............92mph in 2nd with taller tires = 3.29's.

 

 

*I* think he has 3.29's.

 

His tires BTW are 235/50R18's............taller than the GTP OR Bonneville by a bit.

 

Also, be aware that the programmed in (via DHP or other software) shiftpoints on a 65-E are not usually where they actually SHIFT............there is almost always some lag (especially for 1-2).

 

 

Throw in the fact that modded cars usually slip the rpm a little more due to the etra power and we now see why your Bonne shifts where it does..........

 

 

On that note....one other point: a STOCK GPGT (with 3.29's and 225/60R16's) WILL go 87-89mph in 2nd gear before the 6K (5950...whatever ) rev limiter cuts. I've done it at the drag strip (in 2 seperate cars)...........usually a totally stock car will know it has a good run because it'll hit the 2nd gear limiter just as it goes through the traps (trapping at 88ish with hopefully a 15.7 or so under it's belt).

 

By my math, a 235/55/17 is only .07" shorter than a 235/50/18. My math *could* be wrong (doubtful since I used a tire size calculator program...but still possible), but realistically they are essentially the same size tire. So this isn't really a factor since air pressure, sidewall stiffness, weight in the car, etc.... all play a bigger factor on that than this slight difference.

 

I understand there is a bit of slippage in the shifts, so the programmed shifts are not usually where it actually shifts. However, my shifts I posted for my car are where it ACTUALLY shifts not where its programmed. My actual commanded shift points are 6150 1-2 and 6300 2-3, and it actually shifts at ~6450 for each shift. (some of that is my torque convertor as well) However, this ~1-200rpm difference makes approx 1mph difference in 1st gear and 2mph difference in 2nd gear. Give or take the 1-2mph and he is pretty much right there with the Bonneville numbers I listed.

 

I'm pretty much 100% sure that his car has 2.93's. Not sure why everything you look up would say it has 2.93's, and the shift points would match up to everything I've seen, yet they would actually put 3.29's in it......it just doesn't make sense. Pull the diff out and count... My money is on the 2.93's.

 

3rd gear would really tell you the difference. 2.93's would have a significantly higher top speed in 3rd than 3.29's do. Holding the shifter manually in the gears would give you a better idea as well because you can see the mph at the rev limiter and not the shifts.

[Canada]

I don't know anymore...

 

I did drive a 2006 Impala LT with the 3.9 today, it shifted 1-2 at 6200 rpm all on its own.