Hello,

I just bought the Hypertech programer for my 03 Silverado with the 4.8L engine. I read the instructions to tune my truck and did a very basic tuning such as...

87 Octane Gas
Shift Firmess On
Rev Limiter 5500

Shift Points....
1st Gear +3
2nd Gear +5
3rd Gear +8
4th Gear +10

That was all the changes I made to the tuning. All I currently have is the 40 series flowmaster dual exhaust, but everything else is stock.

When I accelerate in 1st Gear... my truck revs past 5K and will not shift out of 1st gear until I release the pedel, then it pops into 2nd. While it is stuck in 1st gear it makes a popping sound under the hood which scared the heck out of me.

I pulled over and returned everything to stock. I then reprogrammed with no modified shift points and the problem doesn't happen anymore.


Can anyone recommend shift points for the 4.8L engine, with only small engine modifications?

Best Regards,
Ryan

check out the first sticky. It's for a 5.3 but this should give you a working starting point.

check out the first sticky. It's for a 5.3 but this should give you a working starting point.


I was just looking at that... It was later mentioned that it was for a highly modded engine, and all I have is an exhaust system

I will give it a try...

sounds like the rev limiter is set too low, compared to the added mileage you set for the 1-2 gear mph. Try raising the rev limiter to 6000 or lower the mph for shifting.

sounds like the rev limiter is set too low, compared to the added mileage you set for the 1-2 gear mph. Try raising the rev limiter to 6000 or lower the mph for shifting.

Makes sense... I guess the extra 3+ mpg will raise the RPMS significantly in first gear. It sure was wierd hearing it stick in 1st and making a popping sound coming from the engine somehere... I've have to try again with a higher rev limiter setting...

6K for the RPMs sounds pretty darn high for a V8... but I guess as long as I don't sit at those RPMs then I should be fine...


Thanks for all your help

hi incres rev to 5900 or 6000 or lower the shift to 1 or 2 +
an my 2000 5.3silv
1/2 3+ 2/3 8+ 3/4 10+
rev 6000
the shifting only work good from stop like when you drag race its gone hold longer shifts like from 1 to 2 or 2 to3 3 to 4
i thing your rev was to low or shifting from 1 to 2 to much lower them
to 1+ or 2+ and you see
my silverado shifts 1 to 2 at 5900rpm
if rev is to low its not gone shift
or IF shifting pints are to low
i hope that halp you

Thanks for the reply...

I changed the shift points to...

1-2 +1mph
2-3 +8mph
3-4 +5mph

Rev Limiter -> 5900



Performance gain was noticed... Do you think I can change my shift points even higher and raise my limiter to 6K? Is that really safe?

6K for the RPMs sounds pretty darn high for a V8... but I guess as long as I don't sit at those RPMs then I should be fine...

Heh, heh... Tranny didn't shift on me one time tonight and I hit the rev limiter. I checked the memory on my tach, and it was at 7000. Now that will scare the hell out of you!