Harleysoldier66

Hey Everybody!

I am needing information about the stock differential in my 2020 GT Premium.

How and when does the limited slip become posi trac? Is it a setting in the computer or is a mechanical feature? Flip of a switch or automatic when launching?

Bert

"limited slip" means the differential will not allow one wheel to spin a lot faster than the other. It is active all the time, you cannot turn it off. If you do a burn-out or hard launch where you get wheel spin, you should get both wheels breaking loose more or less the same, not just one wheel spinning while the other one coasts.

I'm pretty sure "posi trac" is a brand name for a similar function, I think it might be a GM trademark or something

The differential uses clutch packs that will wear out eventually and it will become an "open differential" meaning one wheel can spin without the other; but under normal conditions that should take a very long time . . . my 2010 has seen a fair amount of road track time, which is very hard on the differential, and it went "open diff" in 2020 with over 100,000 miles on it.

Why do you ask?

Harleysoldier66

Ok. I am new to computer tuning and was told that once a tune is downloaded into the car, the various driving modes (sport, sport+, track, drag, snow/wet, and normal) will be overridden. I do not know if the diff on this car locks when in drag mode or if it is a mechanical initiation. Ultimately, I only want the extra power in my tunes after my bolt on mods are complete. I DO want the driving modes to function in concert with the tunes rather than against.

Are my concerns valid? Or am I just overthinking?

Bert

If you are considering tunes, best thing to do is to talk to the tuner (the people writing the tunes) and ask them about the specifics; don't rely on internet lore. I think they can turn those things on or off but not sure of the details. If they are not clear about it, go elsewhere.

As far as I know there are no electronics in the differential at all, which means there is no way that the computer can do anything in there -- to make sure, take a look for wires . . . no wires, no electronics, no computer control.

I think if I had that car, I would just drive it for a while . . . I think you will be very challenged to use the performance that it already has on the street.

Harleysoldier66

Thanks for the advice. The tunes are not internet based. We will dyno then tune. But I should have the opportunity to speak with him before the process.

In terms of the performance, I am making the bolt on mods as I go. Once complete, then tune the car for those bolt ons. I have already started the process. Therefore, I really want to see it through.

I started all of this on my brand new car because every time I turn around I am being challenged. And I got beat once. Can’t have that! Lol.

Harleysoldier66

So, I spoke with the tuner. The tunes will NOT override the drive modes, rather amplify them. And the rear differential is mechanical limited slip.