Beretta.net

Hi,
I have an '95 GM 3.1L with 4T60e transmission, I think.. Stock it has 155 hp, I am planning on getting it up

to 200 or so with head work and Camshaft.. I don't want the transmission to be a problem.. I think they made

an 4T60e HD for the autos that came with superchargers.. Can I swap the 4T60e for an 4T65e or 4T65e HD

model without a lot of trouble and would that be beneficial to me?? What R your suggestions and/or feedback..

This is an Z-26 Beretta.. I would like my Final Drive Ratio to be around 3.29 to 3.42 or so..

Welcome to the group I'm not the expert here, but I believe the simplest thing to do would be to beef up your current trans. I know a 3.33 FDR was available in them and you can program them to shift quite fast. 3x00Modified on here is running high 12's with a heavily modded 3500 V6 out of a G6 (around 220HP) plus Nitrous with no issues on his trans. I think you'd spend more trying to get something else to go in it's place.

http://www.gmtuners.com/gmtransinfo.htm
Click on the ID charts to get more info. With my 95 I went with the W body 3.33FDR. Still think the 1994 Quad N body's 3.43 would have been more to my liking. That may be splitting hairs as it's so close.
3X00's trany is built and can take much more than stock. He is the one to talk to about beefing it up as he does his own work.

Yes you do have a 4T60e.

Hi Guys,
Thx. 4 the Replies.. I know how the Final Drive Ratios work with RWD vehicles, but I don't think I understand
how these FWD Transmission FDR's work.. If I have an FDR of 2.97 and I have an 4T60e automatic that has an 4th
gear ratio of .705; does that mean that my overall Final Drive Ratio is 2.09 ?? I am confused.. The reason I ask is
when I look at overall specifications of an Beretta with the 4T60e, it states that 3rd Gear is 2.97 and 4th gear
is 2.09 .. That is really a low number.. My Beretta is an Z-26 and its FDR is in the 3.16 or something like that..

Hi Mr. Pit,
Thx. 4 the reply.. I have seen lists of several FDR's.. These FWD Transmissions/Differentials are confusing to me.. Is the FDR number before or after
the 4T60e goes into 4th gear which is an overdrive ( .705 )?? That would change and 3.33 to 2.35.. On the Website automotive-catalog. ,it has
all kinds of specs.. It states the 4T60e in 3rd gear ratio of 1.000 and this one is 2.97; now it also lists the FDR as 2.97, but what happens when the
transmission goes into 4th gear at the above mentioned .705 ?? Confusing to me.. What is the proper name for what I am calling the Sprocket gears;
the ones that could be 35/35 or 33/37 or 37/33 ??

The FDR is what you would find in a RWD's differential. So it would be like saying that your car has a 2.97 in the rear(only it's in the front in this case).
Just look at the FDR first. Then you can start doing the math to find out what the overall ratio is in each gear. Yes you are correct that the overall ratio in 3rd is 2.97 it is because of that 1 to 1 ratio(one turn of the crank=one turn of the top gear which turns the lower gear via the chain becoming 2.97).

Hi,
Well 2.97 times 0.705 is 2.09; man that is low number; at 3000 RPMs in 4th gear, the vehicle should be doing 120 + MPH
or am I missing something.. (Just guessing)
Do U know the correct term for what I called the Sprocket Gears?? Examples: 35/35 or 33/37 or 37/33.. And which one
changes the FDR to the higher FDR Number?? (I can see that 35/35 is 1 to 1) Is it the 33/37 or the 37/33 that results in the
higher FDR number??

Hi Guys,
I am back, meaning I have been busy getting my ducks (and some other people's ducks) in a row..
So I have lots of questions.. On the my Transmission, I am thinking about trying to find an 4T60e-HD.. Original is 4T60e..
Is the HD a better and will it help me?? I don't mind spending a little to eliminate some problems down the road..

The only difference between the regular and HD is a different larger differential... The rest of the internals are basically the same. I've majorly upgraded my transmission to support what I do with the car and I JUST did the HD diff upgrade recently... The other setup was surviving just fine but I went to the larger diff for hope of longevity over the SD one in a drag racing application.