Hard Shifting

[mulletman]

i have a 2007 nbs with a 5.3 and 270 000 km's when ever i am stopped at a red light or at a drive through for a long time or even in my drive way in park the Check Engine Light light will start flashing or stay on i check the code and it is p0303 and some times it says there is two codes and they will both be the p0303. after i start to go again after i was stopped and the light came it will hammer 2nd gear so hard that it will some times chirp the tires all other gears are fine and if i am only stopped for a few sec it will shift fine i just changed all the plugs and wires because it was idling rough the new plugs and wires changed that way smoother but still will hammer 2nd gear when the light comes on i just had my tranny serviced 5 months ago and i am at a loss, is there any sensor like the crank or cam that tie in with the tranny that may be doing it? i talked to my tranny guy and he said that the tranny might have some wore out valves and the tc might be slipping and then it ups the psi when shifting but wouldnt it do that all the time if that is the case and why would my misfire on #3 code come up.

 

Ryan

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i have a 2007 nbs with a 5.7 and 270 000 km's when ever i am stopped at a red light or at a drive through for a long time or even in my drive way in park the Check Engine Light light will start flashing or stay on i check the code and it is p0303 and some times it says there is two codes and they will both be the p0303. after i start to go again after i was stopped and the light came it will hammer 2nd gear so hard that it will some times chirp the tires all other gears are fine and if i am only stopped for a few sec it will shift fine i just changed all the plugs and wires because it was idling rough the new plugs and wires changed that way smoother but still will hammer 2nd gear when the light comes on i just had my tranny serviced 5 months ago and i am at a loss, is there any sensor like the crank or cam that tie in with the tranny that may be doing it? i talked to my tranny guy and he said that the tranny might have some wore out valves and the tc might be slipping and then it ups the psi when shifting but wouldnt it do that all the time if that is the case and why would my misfire on #3 code come up.

 

Ryan

 

 

Your 2007 must be a special edition if it still has the 350 in it. Anyway, check your number 3 cylinder spark plug and wire. That's the second cylinder from the front on the driver's side.

[mulletman]

oh sorry it is a 5.3

[mulletman]

as said in my first post new plugs and wires last weekend did not solve problem. the biggest thing is i am wondering if that p0303 code will make the tranny do whats its doing or if i have two problems

[Rat4go]

Misfire code may make the engine ignore the shift torque management request, which may make the shifts (especially the 1-2) feel firm.

 

If it were my truck, I'd fix the misfire code soon!! (or risk burning up the cats!! $$$) Once that's fixed, then assess the trans issue.

[rodram]

I think you have two separate problems..... I don't think that a cylinder 3 misfire would cause the erratic transmission performance.

 

If the misfire code still comes up after you have new plugs and wires, then try some good injector cleaner (some guys swear by Seafoam, but get something that will clean the injection system). Also, just to be sure, check your wires again to make sure they are tightly connected and that none are touching something metal.

 

I think that your transmission may be worn out. The comments you had in your post from your tranny guy sound very reasonable, given that you have 270,000 km (168,000 miles) on this 4L60E transmission. Average time to require major rebuild on this transmission is somewhere around 210,000 to 240,000 km. Mine started the hard bang on shifting 1 to 2 at 211,000 km one day last year after a long highway drive on a hot day. Settled down after everything cooled off, but my tranny guy pulled the pan to diagnose, and recommended a complete transmission and torque convertor rebuild.

 

It runs very good now with the rebuild using upgraded parts.

[mulletman]

well the rough idle is back and i swaped out coil from 3 to 6 no change changed injector from 3 to 8 no change did comprestion test its good over 125 psi i have a small exhaust leak from eather the manifold or the from where is connects to the pip on that side could that cause the problem? that will be my next step fix that and then after that i am going to change the O2 sensor's before the cat on both sides i have over 277000 km's on it and i think they are stock any other ideas? i hooked up a better scanner to it the other day and idle in my drive way for 25 mins and played with it and loged how many times it missfired 11000 times on #3 and random 1 time on others when i rev it up over 1000rpms the missfire goes away and when i am driving around it does not miss would my computer need to be flashed? want to try every thing before i bring it to the dealer and have them burn me for lots of $$$$$ any help would be great

[Mazer18]

I'm not sure if this is the problem or not but I'm just going to throw it out there. When my '07 4.8 had somewhere between 10-15k miles on it I had a harsh 1-2 shift. It turned out to be a sticking Accumulator. Here's my receipt.

 

 

 

 

Just something for you to look into. With as much distance as you have covered it could be entirely something else.