Advice on my transmission tune.

[ippielb]

Hello, i've been fiddling around with tuning my transmission. And this is what i've come up with.

2002 Silverado Transmission Tune.tun


And this is the log i took, i did a WOT. Yes my truck is slow, whoopie.

WOT log.efi

Let me know.

[joecar]

Looks good to me; are the upshifts firm and definite without jerking the vehicle/driveline...?

Are there any problems you're seeing...?

Regardless of trans, set B3616 to 65% below 3600 and to 35% above 3400.

[ippielb]

The shifts feel like they could have a little more firmness to them, but right now it shifts really smooth, i can barely even feel it shift if I'm driving nice. My first problem is that it shifts too soon on the first gear. It shifts at around 4500 rpm on almost WOT, on D0940 it is set to 5200rpm. When it shifts to 2nd, it ultimately looses too much rpm, but 2nd to 3rd gear is right on 5200rpm. I was thinking of maybe bringing both shift points to 5500, would that be too much? Would i need to really up my shift firmness to accommodate the higher RPM?

Thank you for looking at my tune.

Also, i have knock sensors that need to be replaced, i have the light come on every time i clear the codes, so these ones wont be going away. But would that tame down my knock retard? Because it is all over the place.

[joecar]

To firm up the shifts, try reducing the Torque Reduction tables D0801,2,3.

You could also increase D0801,2 some.


You can edit D0910-22 and D0940-52 to get the shift WOT rpm you want... are the speedo parameters correct for your axle ratio and tire size...?

[Taz]

Hello Brendon,

When GM released the ZZ3 and ZZ4 smallblock Chevy kits “back in the day”, they included reprogramming for the 700R4 transmission that set the WOT shift point to 5800 RPM. This was to help compensate for potential torque loss after a shift - due to the transmissions gear ratios.

The 4L60E / 4L65E / 4L70E have the same gear ratios as the original 700R4, and in my opinion, will accelerate best if the shift RPM is at least 5800.

That said, your 2002 5.3L was factory rated at 285 HP at 5200 RPM and 325 Ft-lb at 4000 RPM. In a hypothetical quarter mile your truck would probably run the “quickest” if shifted in the area of 5800 to 6200 RPM.

I wouldn’t recommend that you run the truck this “hard” all the time, but every once and a while should be OK.


Regards,
Taz

[Frost]

I have an 02 5.3l Z71 with the only mod being a GMPP CAI. I have my truck shifting right at 57-5800 and that's what the butt dyno likes.

[Gordy M]

The 4L60/64E trans like to have the vette servo installed for trucks. Makes the 1/2 shift much crisper and smoother, even when driving normal.

[Taz]

Yes the Corvette servo does a good job of holding the band and has a good 2nd gear shift "feel". Prefer a billet or "super hold" servo for 4th gear. These modifications, along with a TransGo HD2 kit make a durable and great shifting 4L60E / 4L65E. While you have the valve body off to install the shift kit, recommend installing a new separator plate (around $20 from TransGo) - the check balls tend to wear the holes concave or oval - potential to allow a small amount of fluid flow when it should not.

Regards,
Taz

[ScarabEpic22]

Do a vette servo at least, makes a HUGE difference in the 1->2 shift quality. I have one in my 02, thing shifts like a beast with tuning, Vette servo, and some minor internal mods (boost valve, etc).

[ippielb]

Ordered wideband o2 sensors, and new header gaskets(mine are leaking already), also new knock sensor pigtails to go with new intake manifold gasket, and new knock sensors, to fix my nasty retard on the knock. I am going to be putting a new transmission in my truck in spring, because my reverse disks are pretty much done. Will be getting it built. Thanks for the help so far guys, still struggling with the program, but hopefully when i get my wideband o2 sensors it will give me a lead to go on.