Is a 2.56 really an awful gear set?

Over on the impalass board, I asked about tuning to get rid of a condition where when cruising on the highway at 75, if I let off then press the gas again, the torque converter unlocks, revvs increase for a second, then it locks back.....regardless of if I'm going uphill downhill under load, coasting etc. it's pretty darn annoying to me.

Yes, it can be tuned out, but the overarching consensus was a 3.42 or other gear set is what our cars need, and the 2.56 is trash.

I won't race, I won't full-throttle pull....I'll probably never pass someone. I drive highway and 50mph roads and would like the best mpg I can get. I was really surprised with the hatred, and could understand it I wanted a performance car or similar. If I were to slip & fall into a donor for peanuts or free I may consider a swap, but to throw gears at a perfectly good rear end seemed foolish.

Thoughts?

As with everything in life, it depends what is important to you. The SS bunch would lean much more towards performance than anything else. The 2:56 is fine for a daily driver. The ECM should manage the convertor lock/unlock almost imperceptibly if working properly.

Any time you accelerate the torque converter will unlock. With the 2.56 it is more aggressive in doing so, because of the tall gear ratio. When you accelerate, the engine needs to be in its torque range, and you are almost, if not, out of it with the lockup engaged.

After driving my 96 Roady wagon with the 2.93 rear tow-pack gears for years, I drove a friend's 95 wagon with the base non-tow-pack rear, and it felt like the parking brake was on!  

I was really shocked by how gutless it felt on the highway...where my car only downshifts on steep hills, that base car was dropping in and out of overdrive on even smaller inclines.   It's no surprise to me the transmissions in those base cars don't live as long...they work HARD shifting up and down all the time....unless you live in Florida or somewhere FLAT.

The 2.93 still seems high but is a good ratio on the LT1 cars.  I've heard putting a 3.23 from a TBI car into an LT1 wakes it up even more.  Have always wanted to try that.   I would be a little concerned about 3.42 here in Texas though with our 85mph highways...that might take away some of that 90mph "loaf" my wagon has.   The motor does not seem to be working hard at 85-90 with the 2.93s and still gets decent mileage.  

-Mike

To change the TCC unlock/relock, there's literally ONE CHECKBOX in the tune that you change.  That's it. Then the TCC will stay locked unless you change gears or hammer the gas pedal. If you have a '94-95 you can do it yourself via TunerPro and eehack for free (buy a USB to TTL converter off Ebay for $5 and wire it into your ALDL port and that takes care of the interface).  

As for the 2.56, depends on your driving.  If you do a lot of highway driving and you don't care about max acceleration, 2.56s are fine.  If you're all around-town, yeah, keep an eye out for a 2.93 or 3.23 axle.

I will say that this '92 Sedan I refurbished last year was SUCH a nice car, but with the base gearing, even with the TBI 350, it was a real DOG. It WOULD get up to 85 on the highway, and the motor was just barely spinning even at that speed...but it took...patience..


My 92 Custom Cruiser wagon with the exact same 350 TBI and 3.23 tow-rear and it was MUCH stronger, but the motor was spinning much faster at highway speeds too!



I'm still trying to convince Richard to swap that rear on the '92 Sedan. That sedan is a fantastic car, only let down by that rear! We'll see!

-Michael

The TBI Buicks came with either 2.73 or 3.23 gears.

Fred Kiehl wrote:

The TBI Buicks came with either 2.73 or 3.23 gears.

Really? I knew my Custom Cruiser had the 3.23, but figured that 92 Roady Sedan was a 2.53 since it's so pokey. Man he really needs to swap a 3.23 into that car.

Projects!

-Mike

This debate comes around regularly as new owners learn,..

My personal experience leads me to come to this conclusion,
Its all about topography. You're a flat lander? 2:56's wont bother you at all.
You most of your driving in town 2:56's won't bother you.
We have hills in my parts of the world and 2:56's are soul destroying here. Converter is unlocked and you are pulling hard in 4th to climb a hill as the speed is dropping off.
I get bettter fuel mileage with 3:73's than i ever have with 2:56. You come to a long rise/hill and the car motors up the hill with no effort with the converter locked.
I also have the brake switch for the converter bridged so the converter stays locked as i'm braking untill it reaches it disengage mph. Converter lock and unlock pounts can be manipulated in the ecm programming

I have kept my fleetwood stock so far,. But the only mod i am seriously considering is a ratio swap.
Car is great at 80+ mph carries its speed pretty good,. But cruise at 60 and its a sluggish brute unless u boot it hard.
Most owners that drive either a3:42 car or a 3:73 car are amazed at how the personality of the car is so different
Jm2c

Something to consider,. 2:56 in 3rd gear is close to 3:73 in 4th gear
3rd gear locks up too with shifter placed in 3

This new Hillbilly can attest to the hills not liking the 2:56 gearing. The word "YIKES" comes to mind. My Roadmaster did not enjoy the Blue Ridge Parkway. I wont take it back up there.

Yes, the 2.56 gears SUCK.