Jump to content

Braking

Dmendrin

Recommended Posts

Dmendrin Enthusiast

Dmendrin

Posted
Posted

I have a couple of question to see if anyone else is having these issues. The dealer is stating that no issues are found but clearly its something unless we all have the same issue. On my 2014 Silverado LT my break pedal is now squeaking when I apply pressure to break. I can feel with me foot a spongy feeling as well. It doesn't feel right at all. Also else having this issue? Also when coming to a stop or at slow speeds in traffic on and off the gas and break ill hear from time to time (at least 3 times a week) a thud in the trans and jerks the truck. I know everyone will say take it in. I have and they couldnt get it to happen after burning a full tank of my own fuel. Anyones help or direction will be awesome. Thanks.

fondupot Senior Enthusiast

fondupot

Posted
Posted

ahem.....brake.....braking.....brakes.

 

That being said. I have not experienced this issue. My brakes feel normal and my pedal does not squeak. Perhaps you can apply a bit of grease to the pedal mechanism to try an eliminate the squeaking.

 

And about the thud you are experiencing. With trucks having a leaf sprung rear end, the rear drive shaft needs to be able to slide in and out of the of the transmission housing. As the suspension goes through its range of motion, which on a pickup truck is quite large. The drive shaft needs to lengthen or shorten slightly to accommodate the rear axle going up and down in its suspension travel. This is called a slip yoke. In traffic where you would be on and off the gas and brakes, it is common for the slip yoke to make a bit more noise than normal.

 

If it really bothers you, I would take it back to the dealer and ask them to re-grease the slip yoke because you are experiencing a lot of slip yoke noise.

 

Any pickup truck I've ever driven has had that characteristic. The only way to totally eliminate slip yoke movement is to install a slip yoke eliminator kit. Which I do not believe is available for the new trucks. Vehicles with independent rear suspension do not have this characteristic because then the drive shaft is fixed between the rear diff and the transmission.

Dmendrin Enthusiast

Dmendrin

Posted
  • Author
Posted

Geeez I feel like a idiot. I should drink a cup of joe first. Dumb award goes to me for the day. And thanks for the info fondupot.

GMCustomerService Senior Enthusiast

GMCustomerService

Posted
Posted

Hello Dmendrin,

 

I see that your fellow forum members have provided you with lots of advice. I might not be able to provide you any technical support but if you have any lingering questions or concerns please contact me via private message. I would be happy to assist!

 

Jennifer T.

GM Customer Care

2strokesmoke Enthusiast

2strokesmoke

Posted
Posted

Geeez I feel like a idiot. I should drink a cup of joe first. Dumb award goes to me for the day. And thanks for the info fondupot.

What you are feeling I believe is.

Your truck shifts up through the gears very quickly as you accelerate, and if you have to come to a stop very quickly the transmission has to downshift very quickly too!

Now here is where it goes wrong, the tranny is shifting down a gear or two that brings up your engines rpm and torque and your attempts to stop this force makes your brakes feel less effective during this particular time.

Your brake's pedal force might feel somewhat soft or less effective, followed by the drive shaft thunk that most feel when they have to stop fast, or quick throttle and quick release of throttle with current gear at top of it's rpm range.

This thunk is what engineers and mechanics might call axle wrap! Torque from engine and a gear at it's high rpm range and sudden brakeing force only results in something has to give.

Rear axle pivots forward large amount of energy is released, causing the leaf springs to thunk up against each other, or drive shaft forward thunk what some call slip yoke noise. The real problem GM keeps making there leaf springs lighter and more flexible allowing the leaf springs to absorb road energy for comfort, at a price of axle wrap energy transfered to suspension components.

A toyota mechanic was very adamant in fixing this problem on his customers light trucks and found that clamping a small leaf plate and a set of ubolts together forward of the rearend 2" eliminated the known axlewrap thunk.

I know this worked for the 2013 sierra and silversdo. I have not tried it for the 2014's, this fix preloads your rear leafsprings somewhat removing most of this daily thunk you would feel while stopping quickly.

GM needs their transmission's to down shift very quickly allowing the transfering of this energy to the suspension without mechanical weaknesses and noises of energy release to truck.

a forward facing tuned shock would remove this axle wrap like what is on large monsters trucks at shows.

just my 2cents worth.

haider320 Enthusiast

haider320

Posted
Posted

 

now that right their they're there (damnt!) is funny!

 

 

lmao! Usually on this site; it's somebody mentioning something about their "grill". It's grille people!

Archived

This topic is now archived and is closed to further replies.

Go to topic listing

  • Recently Browsing   0 members

    • No registered users viewing this page.

  • Forum Statistics

    250.4k
    Total Topics
    2.7m
    Total Posts

  • Member Statistics

    342,840
    Total Members
    8,960
    Most Online
    appletrav
    Newest Member
    appletrav
    Joined

  • Who's Online   3 Members, 0 Anonymous, 366 Guests (See full list)

  • Latest Articles

  • Posts

    • newdude
      2 speed transfer case optional now?

      By newdude · Posted

      This is a 1/2 ton thing ONLY.  All HDs 2020-2026 have the two speed transfer case, with Autotrac as an option.     1/2 tons 2019-2026, regular 4x4s come with a single speed case (no 4LO!), and trucks with Z71 ordered, or all Trail Boss trucks come with the 2 speed case.  2 speed case is also an option on WT, and is also standard on High Country.  
    • newdude
      Different requirements for oil filters?

      By newdude · Posted

      2013 5.3 still to this day calls for the PF48 filter.  Which as a 15psi bypass pressure.     There is a TSB, 17-NA-157 that talks about the PF-63 and PF-64 filters which have a higher bypass rating of 22psi.    TSB HERE - temp.xml   "Beginning in 2012, the oil pumps began to regulate main gallery feedback instead of pump out pressure. This means that the oil pump now does not begin to regulate until pressure is built up to the main gallery. This change reduces the amount of time it takes to provide oil to the engine bearing and lifters during extreme cold start conditions.  Main gallery feedback oil pump control systems are present on the following engine families which use Spin-on oil filters: Small Gas Engine (SGE), Large Gas Engine (LGE), High Feature (HFV6) Gen2 and Small Block Gen5 gasoline engines. These engines with the main gallery feedback oil pump control systems are factory built with an ACDelco® oil filters"   It also calls out what engines use those filters.  The gen 4 small blocks were not on that list (LMG, LC9, L9H, L92, L94, L20, L96).  Gen 5 small blocks use the higher pressure filter.          That all said...   Your 7045 Napa filter is the PF63 equivalent, with 22psi bypass.  You are already using the higher bypass pressure filter.  You CAN keep using it, you don't technically have to use it though.  
    • Grumpy Bear
      Different requirements for oil filters?

      By Grumpy Bear · Posted

      Do you know WHY the filter relief setting was increased to 22 psig?    When the new system goes into the second stage the pump volume ramps up considerably. It was found that the 15 psi filter bypass setting put the filter in bypass on a warm engine when the second stage was activated. Raising the filter bypass setting forced the filter to do what it designed to do. Filter. Preventing debris from circulating during high load, high rpm operation.    So next question is how did GM find this out? VLOM/lifter failures and a deep dive by Melling Corp.    Last question. Is it required? Look at it like this; a motor may be equipped with a rev limiter. But it only works if the set point in reached. That 22 psig setting only matters if the pressure differential across the filter media exceeds 15 psig during normal warm operation. Second stage kicks in around 3000-3500 rpm.    I can't answer your question because I don't know you and how you use the truck. But I think there is enough information here to let you decide for yourself. 😉
    • Coastie05
      give me some tips to make my truck look better

      By Coastie05 · Posted

      Go back to OEM wheels. 
    • newdude
      2020 Trailboss 6.2 replacement

      By newdude · Posted

      Probably not their first rodeo, so it should go as planned most likely.  Typically the service manager or tech doing the swap will put some seat time to shake it down after they get it all put back together.  We usually put 50-100mi before we hand them back so if something happens, its not after you get it.  A coolant leaks, oil leaks, a ground left off or loose, vibration, etc.     The new engines so far have been good?  There's been a couple that have popped out there again (the replacement engine) but most have been okay.  

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...