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Rough Shift Between 1st And 2nd

b_zieman

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b_zieman Enthusiast

b_zieman

Posted
Posted

Okay, i Have an 03 sierra 1500 4.8l. I bought the truck with 10,000 miles on it. I now have 60,000 miles . Since I can remember the truck has always shifted very hard between 1st and 2nd. Hasnt ever missed a shift. Very annoying. Is this something that can be reprogrammed?? Any ideas?

 

Thanks!

2500ak Enthusiast

2500ak

Posted
Posted

Firm shifts are actually a lot better for the transmission, gas mileage etc. If it's a really hard, no non-sense shift then I would conjecture that perhaps the previous owner might have put in a shift kit or a vett servo. Either way, hard shifts keep the clutches from slipping against each other. And punmax most likely has a completely different transmission. If you have a 4.8L I'd guess you have the 4L60e.

 

As a side thought, the previous owner could have used PCM tuning to remove torque management, you could have the dealer reflash the PCM to see if it would restore it to those soggy shifts.

2500ak Enthusiast

2500ak

Posted
Posted
my 07 yukon does this too...intermittently... sometimes it doesn't move and i have to shift back to park, then into gear.

 

 

Thats not normal, if your truck was older I'd guess it would be something in the valve body sticking. You might try a treatment like transtune, that new seafom product then change the fluid.

 

One thing you can do to soften shifts is switch to a fully synthetic ATF. It'll create a bit more slippage, but not a significant amount. But if you have a shift kit or servos the shifts will remain nice and positive, and maybe a bit less jarring. Me? I like to be slammed around it just plain fun. :rolleyes:

98 Z71 SLT Senior Enthusiast

98 Z71 SLT

Posted
Posted

Disconnect your battery overnight.

 

Reconnect in the morning, and drive regular.

 

Disconnecting the battery overnight resets the "shift-adapts" in the PCM.

punmax Senior Enthusiast

punmax

Posted
Posted
Disconnect your battery overnight.

 

Reconnect in the morning, and drive regular.

 

Disconnecting the battery overnight resets the "shift-adapts" in the PCM.

 

Really?

pm26 Senior Enthusiast

pm26

Posted
Posted

On disconnecting the battery: always disconnect the negative cable. No need to disconnect the other one.

 

I have never experienced rough shifting in my truck, and most of driving is in city traffic. However, my neighbor's 04 extended cab Sierra Z71 with the same engine had really harsh shift between 1st and 2nd , accompanied by a loud clunk when he was towing something. Which led him to not using the tow mode to tow his Bobcat around. Which led to total destruction of the transmission before 35k miles. So do not try to tow 10k lb trailer with a 1500 series truck without using the tow mode. Or preferably, never try it at all.

For some reason, crew cabs clunk less. I do not feel any clunk in my truck, even when towing a 5k lb trailer. And the transmission shifts really nice and smooth with a moderately heavy trailer in tow (in tow mode of course).

blueflavor Enthusiast

blueflavor

Posted
Posted

my 2000 does it to i know i just had the yoke switched to the nickel plated one and it softened it up a bit but i am gonna try that reseting the bat maybe mon. were getting some crap weather here

  • 3 weeks later...
inkpusher New Member

inkpusher

Posted
Posted
my 07 yukon does this too...intermittently... sometimes it doesn't move and i have to shift back to park, then into gear.

 

 

Thats not normal, if your truck was older I'd guess it would be something in the valve body sticking. You might try a treatment like transtune, that new seafom product then change the fluid.

 

One thing you can do to soften shifts is switch to a fully synthetic ATF. It'll create a bit more slippage, but not a significant amount. But if you have a shift kit or servos the shifts will remain nice and positive, and maybe a bit less jarring. Me? I like to be slammed around it just plain fun. :flag:

 

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