Stock Transmission Ratios

[1995 RedVette]

I have a 95 Vette auto. and was wondering what the stock transmission is (4L60E?) and what the ratios would be for that transmission. Just tring to do some math about possible gear swap and wheel/tire swap.

Brett

[tlong]

Check the RPO code for the tranny. Most are 3.07 with a few 2.59. The list is under the door over the amp and jack behind the passenger seat. I think the 3.07 is G92. Hope this helps.


Tim

[jenavet]

i think what brett is asking is what the first, second and third gear ratios are inside the trans itself...thats pretty interesting to know because you can pick up alot of additional 60 foot time/acceleration performance by playing with ratios and or setting up the rest of your combination to work best with the ratio thats in the stock trans...i am not sure what they are. i would think lingenfelter performance or some of the race trans shops like ati or coan might know.

[1995 RedVette]

Thanks guys, I will check Lingenfelter and see if they have any information one the web. And yes I was wondering about the transmission ratios, however, I didn't know about the G - codes for the rear end. I simply jacked the rear of the car and spun the drive shaft until one full rotation of the rear wheels was accomplished. This gave me a hair over three turns, so I assumed that my car has a 3.07:1 rear ratio.


Brett

[garycr14]

Your RPO code should be listed on the inside of your center console lid. The G92 is the 3.07 rear end gears. I do not know about the trans ratios. Keep us posted about what you decide to do with your gears. I have been thinking about 3.55's in the future, would like to know what you come up with, how it works out both performance wise, and what it does to the fuel economy.

Thanks.

[Grizzly]

Originally Posted by 1995 RedVette

I have a 95 Vette auto. and was wondering what the stock transmission is (4L60E?) and what the ratios would be for that transmission. Just tring to do some math about possible gear swap and wheel/tire swap.

Brett

My Vette Specs book lists the 700r4 and the 4L60E as having the same ratios, 3.06,1.63,1.00, and 0.70.

I to am curious about the mileage and top speed lost and gain in the quarter mile with something like 3.55's and an auto trans. Anyone have any info? That double overdrive 0.50 sixth gear in the manual makes running almost any gear within reason possible.

[vettered91]

These are from another CAC member and are posted somewhere here in the forum: (I just can't remember who, right now).

Assumption: Tire Diameter = 25.7in (275x40/17), Drive Ratio is 1.0, Overdrive Ratio is 0.7 (this is for an auto of course). 5400rpm is max with factory PROM/Chip.

In Drive (ratio is 1.0)

Ratio 2.59 3.54 3.75

MPH RPM RPM RPM
----- ------ ------ ------
45 1524 2083 2206
55 1862 2545 2696
65 2201 3008 3187
75 2540 3471 3677
85 2878 3934 4167
95 3217 4397 4658
105 3555 4860 5148
115 3894 5322
125 4233
135 4571
145 4910
155 5249
165

In Overdrive (Ratio is 0.7)

Ratio 2.59 3.54 3.75

MPH RPM RPM RPM
----- ------ ------ ------
45 1067 1458 1544
55 1304 1782 1888
65 1541 2106 2231
75 1778 2430 2574
85 2015 2754 2917
95 2252 3078 3260
105 2489 3402 3604
115 2726 3726 3947
125 2963 4050 4290
135 3200 4374 4633
145 3437 4698 4976
155 3674 5022 5319
165 3911 5346


The formula works as follows:

For Drive (ratio 1.0)
RPM = ((RE Ratio * MPH) / Tire Diameter) * 336

For Overdrive (ratio 0.7)
RPM = (((RE Ratio * MPH) / Tire Diameter) * 336) * OD Ratio

So if you want to calculate different rear gears or final drive ratios just plug it into the formula. Or use the tools on this website or many others.