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Inconsistent transmission

juf

By juf
in Troubleshooting & Recalls

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kpeterson Enthusiast

kpeterson

Posted
Posted

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!

 

 

Sent from my iPhone using Tapatalk

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juf Enthusiast

juf

Posted
  • Author
Posted

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 Enthusiast

brandonbvr

Posted
Posted

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.

  • 2 weeks later...
brandonbvr Enthusiast

brandonbvr

Posted
Posted

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 Enthusiast

sugarjohnson

Posted
Posted

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 Enthusiast

sugarjohnson

Posted
Posted

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 Enthusiast

brandonbvr

Posted
Posted

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 Enthusiast

2strokesmoke

Posted
Posted

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 Enthusiast

brandonbvr

Posted
Posted

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 Enthusiast

brandonbvr

Posted
Posted

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.

  • 1 month later...
Fryguy Enthusiast

Fryguy

Posted
Posted

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 Enthusiast

14SLTZ71

Posted
Posted

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/

14SLTZ71 Enthusiast

14SLTZ71

Posted
Posted

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

Sent from my iPhone using Tapatalk -

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.

  • 3 weeks later...
2014 Sporty Shorty Enthusiast

2014 Sporty Shorty

Posted
Posted

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.

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    • Chuck FB
      Tire psi

      By Chuck FB · Posted

      I will admit I haven't experimented much with pressure drops beyond the numbers I put in and part of that is that the numbers I used are fairly low and then found out it would trigger regardless at that 35 psi. Having said that I had tried before had changed the placard pressures and being that I have a 1 ton set to 80 on the placard for the rear I believe it triggered close to 60, the front I don't recall now for sure but thought maybe it could get close to 45 from that factory 60 placard pressure. So I never did figure out if it was a number of psi from placard pressure to the alarm or a percentage of the total placard number as some figured it was like a 25% drop from placard pressure would trigger it. So as to try and answer your question, I believe I set the placard pressure on the front to 47 or so and while I run the front tires at 40, they have dipped below that some if its colder and I haven't put "winter air" in yet and never once have had the front alarm go off. I would say that the answer your looking for is no, that if you set your placard pressure to 45, you have a certain amount of room to drop below that pressure before the alarm will go off.    The pressures you decide to run in your truck, that ends up being what makes sense to you based on what your carrying in your truck or if towing, then have to bump them back up to something that will carry the load in the rear and the fronts typically left at the same pressure. It all comes down to that chart I put the link to and using an accurate roadside scale to be your guide, both unloaded and then loaded to know your minimum safe pressures.    I just wish GM would allow a person to change the readings for the tire pressures to the English system of pounds as I have to look at that goofy metric reading that will never ever jive in my head and will go over and change it just to figure out what they are if need be and then change it back. 
    • TrueBlue
      No Software Updates - Old Build

      By TrueBlue · Posted

      That part I understand, that the dealer can do it. But I'm not understanding why updates that were available to the truck since it left the factory, or the dealership originally, would not still be available to it without dealer intervention.   I'm thinking along the lines of recalls. They stay available until they are completed. Why not updates as well, especially since some of those can be safety related also?
    • jgaudet99
      Tire psi

      By jgaudet99 · Posted

      That's good to know, but I don't think I'll even be running them under 45 in the rear  unless it's on the sand or something but will only be for a short distance anyways!    I didn't read all the instructions in the booklet yet, but do you know let's say I set the rear psi on the placard to 45, will the warning light come on soon as it drops under 45 or is there a percentage it has to drop from the set value before the warning light is triggered?
    • newdude
      Would this CV Shaft be bad?

      By newdude · Posted

      That's bad.  Like, its probably destroying the stub axle the CV slides into.   Do you have a proper lift installed with differential lowering brackets?  Did you install AT4/Trail Boss factory CV axles?  
    • PunchT37
      Would this CV Shaft be bad?

      By PunchT37 · Posted

      Hot? New Jersey? Today? I was working on my old 2000 Silverado 1500 today. Believe me, it was boiling hot today. As it has been.

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