i just got my car back from the shop after getting a tranny rebuild and. i notice at a stop i let off the break and dont really move, before i would let off and it would go no prob, it also feels like iv lost some power? i used to be able to lite up the tires without trying now i give it and just get a little spin.could this be something done wrong by the shop? torque converter maybe? it feels like a totally different car now the shifts are great but lost some power. any help on this would really help me, im going back tommorrow (manger is off today)

Is it possible that you're used to driving it in "performance mode" and now it'* set to "normal mode"?

The fact that the car doesn't move when you let off the brakes, yet it used to, sounds like maybe it'* idling at a lower RPM now too?

i talked to another tranny shop today he said the stall speed in the tourqe converter might be wrong, i also talked to the guy that rebuilt my tranny and he said if anything the stall speed would be higher and i would benefit from that, does anyone know what the stock stall speed is? he said it was 1850 and thats what converter they put in and how would i benefit from a higher one? it really seems like iv lost low end, i know low end isnt the greatest to begin with but, i just want back what i had before. the cars idle is the same that it always was. i always drive in normal, sometimes i use perform.

Mine hardly moves when I let off the brake, sometimes not at all, esp if I'm on an upslope. Same way before and after tranny rebuild.

If your brakes are good you can find roughly where your stall speed by holding them and pressing the gas pedal. What rpm does your engine stop? Bada bing. Another way is to suddenly snap to WOT and see what rpm your engine jumps up to. This is called "Flash stall speed". Using a stall speed too low or too high will actually hurt performance causing slow launches and low ET'*. Take this clip from www.converter.com:

Selection of the right stall speed for your vehicle should be matched to the engine peak torque, engine torque curve shape and vehicle weight.... When selecting stall speed without having prior experience to go by, it is better to conservatively estimate the engine torque than it is to over estimate it. If you over estimate the torque output you will have a converter with a stall speed too low, making your car slow off the line and have slow ET.


And this from www.fbperformance.com:

Too low of a stall speed will result in a bog, and launches will be slow, since the engine will not be in it'* usable power range. Too high of a stall speed will result in the engine reaching its peak power range below the rpm. Since the converter can efficiently transfer power, this could result in excessive slippage.


Hope it helps

you mean floor the gas with the brakes on?

yup

ok i did that and i got about 2600rpms now would that make my stall speed 2600? the tranny shop said they put an 1850 stall converter in. im lost and confused. I still dont now what im suppossed to have, dealships can help me, they dont know.

OK this is kinda getting i know sorry but just one more question.

my car came with a 2.97 drive i looked at the techinfo (rpo codes) and saw there were different ratios available were these "optional"? or did they come with different trim lines? the reason im asking is because the tourqe converter is pretty much the same but im kinda thinkin maybe they installed a different gear?????

I tested thos on mine last night. With brakes, I can get a little more than 2600. Punch it without brakes from a stop (well, as hard as I can without peeling out, which isn't much), and the tach jumps to 2000.