Inconsistent transmission

[kpeterson]

My transmission does all the same stuff, it sucks, but I am more intrigued with the farts on a cooled seat. Thanks for the tip. I will be sure to test that when my wife is with me!

 

 

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[juf]

Well I'm glad others have experienced some of the same issues. Thanks for the TSB. I'll show it to my service dept and see if it gets me any where.

 

I had Lew tune my truck for me. Honestly, I think he did an excellent job at making it drive better considering what he's working with. I need to shoot him an email and see if we can tune out some of the eagerness to shift too quickly. I'd recommend him to anyone. Like I said, it seems like a mechanical issue to me.

 

I do think they over engineered everything for gas mileage on these trucks - just too much going on. I'd rather get 4 mpg less and just have the truck drive like it should. I heard the new ford f150 will have a "sport" mode.... Would've been a nice option on our trucks.

 

I was alone during my fart experience and the cooled seats. I do hope to have someone in the back seat next time. Direct line of fire.

[brandonbvr]

I observed coming home from work this morning in cooler temps my truck rode like a cadillac at all speeds that were previously giving me shaking and vibrations (70-80mph). My tires are Michelins set to 32 psi cold (recommended on door tag). It was 60 degrees F this morning on my 30 mile all highway commute home. My trans temp was 170 degrees F. I also didn't experience any harsh downshifts or clunks on decel.

 

Something tells me that something in the driveline is out of spec or warps when it is hotter because when it is 80 degrees outside my truck doesn't ride this nice on the highway that's for sure.

 

Has anyone been able to notice these same results? Any ideas or input? My truck goes back to the dealer on Monday of next week.

[brandonbvr]

I understand the door tag says 32lbs for the tire pressure but which michelins do you have? Are they stock tires? 32lbs seems low for michelin tires.

They are factory size P275/55R20 Michelin LTX M/S2

[sugarjohnson]

Wow, interesting, you got michelin LTX M/S2 tires stock on a Sierra All Terrain?

Regardless 32 lbs seems low for Michelins.

Probably upgraded....I took the junk GY off mine immediately and put same tires on my truck...awesome tires

[sugarjohnson]

I have also had similar symptoms on my 6.2L max tow with 3.73. No hard clunk just noisy at low speeds. Dealer has had my truck this week to look at tranny, fix seat issue and v4 squeak. I was told the service bulletin does not cover my engine tranny combo. So in a way I guess that is good.

[brandonbvr]

thats what I am thinking, but it soulds like he's saying the truck came from the factory with those tires and that's why he's using the tire inflation tag on the door frame to set the tires @32lbs.

I put the same tires on mine as soon as I bought it and I agree they are awesome.

 

EDIT: It doesn't matter anyway, I think I'm getting too far off topic.............

I did upgrade to the Michelins and I just got lucky that morning. Truck rides like crap on the highway again. Been at the dealer for 10 days now. Regardless of what brand tire you run on your truck, as long as they are factory size then you use the door tag recommended psi. They design these trucks to perform and handle based on that psi.

[2strokesmoke]

Tire pressure listed on the vehicle's door is recomended for safe operating, and best ride quality, and best fuel economy.

It is the owners, mechanic's responsibility to purchase install tires that can acheive the psi posted on the door.

You can increase tire pressure, but only to the tire manufacturer s max listed on tire side wall.

Point in case for towing, tires psi are generally increased for better handling. But never more then max and never

under recommended psi for safety and comfort.

10 ply tires are better fit for 1/2 ton trucks, but offer stiffer ride.

One could decrease rim size, say 20" down to say 18" keeping same overall size and ride would be smoother as more rubber between rim and ground.

[brandonbvr]

Maybe this is correct if you keep the same tire size, width, height, and rim as factory (which I see you did) however I am still not conviced because tire manufactures will tell you different. The PSI on the door doesn't mean squat once you start changing tire sizes.

 

EDIT: I highly doubt that the engineers design these trucks to perform to a certain tire pressure.

I think you have it backwards. Vehicle manufacturers specify tire pressure based on the tires supplied with the vehicle and the load that the vehicle is designed to carry. They don't design the vehicle based on a certain tire or pressure.

They don't recommend a certain psi for shits and gigs...

 

http://www.goodyear.com/cfmx/web/gov/police/tire_inflation.cfm

[brandonbvr]

No shit, if you are still using the tires that came with the vehicle and the same size. and they definitely dont sit in a board room deciding on which tire and pressure they want and then designing a vehicle around it............. as you stated earlier..period

Tire manufacturer doesn't make any difference....and no they don't design the vehicle based on that psi. What I simply was trying to say is they recommend that psi for best ride and fuel economy based on the vehicles design. Run your michelins above 32 psi doesn't matter to me.

[Fryguy]

Evening folks. New to this forum so howdy from VA. I've read thru some of the threads and have yet to find this issue that brought me here. I've got a 14 silverado crew cab LT with a 5.3. I've noticed that when I depress the accelerator it seems to take a while before the truck actually responds. What seems like a good second or two of hesitation. I've read some other forums that mentioned similar issues with shifting but not with throttle response. They seem to think it was an issue with the shifting timing and that Chevy tuned it that way to reduce over torquing the motor/ transmission. Any thoughts? Also I noticed today, I pinched it rolling about 30 mph and it responded well until it went to shift then all the power dropped off for a second then it kicked in. Very strange reaction. Any thoughts would be much appreciated.

[14SLTZ71]

Evening folks. New to this forum so howdy from VA. I've read thru some of the threads and have yet to find this issue that brought me here. I've got a 14 silverado crew cab LT with a 5.3. I've noticed that when I depress the accelerator it seems to take a while before the truck actually responds. What seems like a good second or two of hesitation. I've read some other forums that mentioned similar issues with shifting but not with throttle response. They seem to think it was an issue with the shifting timing and that Chevy tuned it that way to reduce over torquing the motor/ transmission. Any thoughts? Also I noticed today, I pinched it rolling about 30 mph and it responded well until it went to shift then all the power dropped off for a second then it kicked in. Very strange reaction. Any thoughts would be much appreciated.

http://www.gm-trucks.com/forums/topic/164100-62-throttle-lag/

http://www.gm-trucks.com/forums/topic/157577-any-way-to-modify-initial-throttle-response/

[dodgehemi0]

Mine does the same thing 2014 6.2 denali. I put it in manual mode and such a huge difference in driving.

 

 

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[14SLTZ71]

Mine does the same thing 2014 6.2 denali. I put it in manual mode and such a huge difference in driving.

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If you put it in M1 - M5 it won't got into V4 mode.

Basically AFM is disabled in M1-M5. That's why it feels different.

[2014 Sporty Shorty]

It amazes me how poorly GM tunes thier engines and transmissions. Now that I have tuned my trucks myself with HP tuners, it's amazing how differently my trucks feel. I feel for the op and the others that are complaining, your not crazy. It just makes me laugh that an amateur tuner like myself can fix all the issues I had with driveability in less than a month of trial and error. Yet these engineers with the best equipment and deep pockets can't figure it out.