6L80 - 377 gears
 

I have a 62 impala with an LS3 and matching 6L80 trans hooked up to 377 gears. The car seems like it is launching in 2nd gear. I have almost 500hp and the tires will not brake loose. if I am anywhere other than taking off the car pulls very hard.
I just changed to 377s as I though my gearing was wrong so now I am thinking its something else. My tuner is going to look at the tuning of trans next week but I am impatient I want answers now, lol. I am running 22" wheels in back on 285 tires so they are tall but something is not right.

I found this forum looking for frame info (frame is next)but seen this section and lots of good reply's so decided why not give it a try maybe one of you had this happen before and its an easy fix?

thank you for your time.

Your tuner should be able to program in your overall wheel diameter and rear end gear, so as to make the transmission do what your car expects, rather than whatever the original program for the engine/transmission was intended to do. With HP Tuners or something similar, your tuner (or you) should be able to work this out quickly by correcting a few basic parameters, unless there is an ABS-related glitch, which may require further investigation. On a side note, with an LS3, you should still be able to burn those tires taking off in second gear; you might be in third.

Someone else here should have something more enlightening, but most on here are focused on the manually shifted side of things.

I m hoping and was looking for reassurance it was just the trans tuning.

we did the math and 377s seemed best but the tires don't brake loose. I can go 80mph and go WOT and it takes off like a bat outta hell but the first gear just kinda feels weird almost like it has traction control or something?
Monday the 13th I have appointment and hopefully its all fixed but until then I stress.

thank you for repling

I would contact Speartech. They are very good with those transmissions. You can send the trans controller to them for programming. Instructions on their website on how to remove it.

Don

I'm going to google them now. Thank you very much

that sounds like a lot of gear for that tranny. most cars run low numberic gears with that tranny don't they? My father inlaw had a 6l80 with a ls9 and 3.89 gears several years ago and it was way too much. Due to lack of computer programing for a ls9/6l80 in 2010 he ended up pulling it out and going t56 magnum

I was thinking the same thing but he said he is running 22 inch wheels so maybe it is ok?

Don

Ya I am not gonna lie I have no clue the math but my tuner and the the shop that installed the gears both recommended 373 sorry not 377. (over all tire height is 30")
can feels great everywhere specially on the freeway its a freight train even first or taking off dont suck but it should smoke the tires at half throttle. I never dyno-ed it as the numbers are not that important to me but its got to be close to 500 at the wheels.

Monday my tuner is gonna plug it in and go over everything I hope its something silly but my luck it isn't.

Your tuner cannot tune the transmission without removing the controller. If you are running the stock transmission controller tune that could be your problem. Which torque converter are you running?

Don

I 2nd that. I spoke to them and that's who I'm sending mine to when it's time.

stock converter.
I have no idea what he is gonna do honestly. I am not smart at all when it comes to that stuff at all. I just know he is and Im taking car to him in 12 hours hopefully later tonight I can post something good