Jump to content

6 speed failure

tlaw91

Recommended Posts

tlaw91 Enthusiast

tlaw91

Posted
  • Author
Posted
Does the pump grinding into the case happen with the 8L90 when it has the factory Mobil 1 fluid that is hydroscopic? 
 
My 8l90 shifts fine but I only have 10k miles on truck. My truck was built 12/2017 which means it has the older Mobil 1 fluid that is hydroscopic? 
 
I haven't received any notice to have the fluid exchanged to the newer type. That is a TSB, and you have to prove your trans is shuddering correct?

There has been no 8 speed failures like this in my shop. 6 speeds all day long.


Sent from my iPhone using Tapatalk
  • Replies 46
  • Created
  • Last Reply
tlaw91 Enthusiast

tlaw91

Posted
  • Author
Posted
I'm not sure. Could you explain it a little bit more?

I’m 90% sure you’re hearing the vacuum pump cycling which they all do. That constant snapping noise, it’s very clear in drive thrus or against walls? That’s the vacuum pump. Totally normal. Rest easy friend. Hope this helps you enjoy your tuck a little bit more!

-GM Tech


Sent from my iPhone using Tapatalk
steelerdude15 Enthusiast

steelerdude15

Posted
Posted
15 minutes ago, tlaw91 said:


I’m 90% sure you’re hearing the vacuum pump cycling which they all do. That constant snapping noise, it’s very clear in drive thrus or against walls? That’s the vacuum pump. Totally normal. Rest easy friend. Hope this helps you enjoy your tuck a little bit more!

-GM Tech


Sent from my iPhone using Tapatalk

Thanks, I appreciate it.

njk4o5 Enthusiast

njk4o5

Posted
Posted

change the fluids all you want it will still fail. the transmission tuning in the trucks kills the trans. My truck was babied and my trans went out at 96k

mookdoc6 Senior Enthusiast

mookdoc6

Posted
Posted

My TRANS guy says same.....8speeds...nope....6 speeds way to many even HD's


There has been no 8 speed failures like this in my shop. 6 speeds all day long.

black00ta Enthusiast

black00ta

Posted
Posted

Agreed, I see 6 speed failures left and right in my shop. This could also have to do with the ratio of 6l80 to 8l90 on the road.  Knock on wood mine is holding strong at 78k miles.

Snowcamo Senior Enthusiast

Snowcamo

Posted
Posted

Mine has 146k currently. It whines every so often and then like a power steering pump. Was gonna drop the pan, but I'll leave it be...

Sent from my LG-G710 using Tapatalk

Rock1500 Senior Enthusiast

Rock1500

Posted
Posted
My TRANS guy says same.....8speeds...nope....6 speeds way to many even HD's

There has been no 8 speed failures like this in my shop. 6 speeds all day long.
Really why?

Sent from my Pixel 2 XL using Tapatalk

Doublebase Enthusiast

Doublebase

Posted
Posted
On 2/5/2020 at 9:33 PM, tlaw91 said:


There has been no 8 speed failures like this in my shop. 6 speeds all day long.


Sent from my iPhone using Tapatalk

Well this is depressing, I have the 6 speed. I figured it would be the more reliable of the two.

 

I have 47,000 miles on it now...I've done two transmission services (one pan drop and the other just a drain and fill through the dipstick). I do get a slight shutter occasionally going up hills on the highway, since new.

 

Good to have you on the site, we need more GM techs around here. I used to be a tech, now I teach automotive...so I'm very much out of the loop in terms of everyday industry trends. I try to stay up to date but it's hard.   

Jaychevy81 Enthusiast

Jaychevy81

Posted
Posted

My boss has a 16 GMC with the 6 speed he had the trans replaced at 80k all highway miles. It lost 3rd gear I have the 8 speed I feel there solid but shift worse then the 6 speeds.


Sent from my iPhone using Tapatalk

black00ta Enthusiast

black00ta

Posted
Posted
On 2/9/2020 at 9:10 AM, silveradosid said:

so is the assumption that no matter how many times you change the fluid the torque converter is still going to fail

Basically. Fluid change is still helpful of course, but this is beyond a fluid issue.

diyer2 Senior Enthusiast

diyer2

Posted
Posted

Simple.

Fluid changes extend it's life IMO.

All this talk of failures.

It's the luck of the draw if you get one with a problem.

My 6 speed has been smooth since bought used with 41 K miles.

Now over 70 K miles.

:)

davevinc1080 Enthusiast

davevinc1080

Posted
Posted

At 77K Miles with the 6 speed. See what happens. I have exchanged the fluid on my own but never a filter change. Also just tuned it with a superchips 2845 so see what happens....... feels smooth. but who knows. 

79Mercy Enthusiast

79Mercy

Posted
Posted

Is there a drain plug on the torque converter that can accessed thru the bottom inspection hole in the bellhousing?

Archived

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

Go to topic listing

  • Latest Articles

  • Posts

    • Chuck FB
      Oil Consumption

      By Chuck FB · Posted

      Ok that confirms the extra quart theme they are still going with which must mean they have noted some initial use more so then some engines and probably the bigger factor in all of this probably isn't the engine so much as its the insane distance or OLM that lulls a lot of the driving public into driving their new vehicle off the lot and not even doing one short interval oil change because the manufacturer doesn't say different and if the dealer follows that logic as well. Selling the rarely needing to be serviced concept seems to go over well with the public that wants to get away with as little as possible for dollars spent on the vehicles maintenance and I bet there are 3.0 engines just like other vehicles out there that never have their oil checked by the owner which goes back to why they probably felt the need to add that extra quart to avoid a costly theme.    Speaking of cutting filters open, it was probably over two years ago now that a youtuber who buys vehicles to do longer term reviews and pulls a fifth wheel through the mountains of Colorado on summer trips and that becomes part of the testing. Anyway he had a GM HD with the 6.6 gas and a Ford 250 with the 7.3 gas at the same time and of no surprise the Ford had more power etc but somewhere along the way in the few thousand miles he put on the truck, he changed the oil and was seeing glitter and cut open the filter and yeah, things were not looking spectacular. The truck about that time or soon after seemed down on power compared to what it had been and then threw some engine code, I expect the cam/lifters were failing and so he brought the truck back to the dealer and made some deal to get out of it as he knew it would sit for months waiting on a new engine as they were so backlogged at the time. He kept the GM for some time after that using it exclusively until he sold it after buying his next vehicle to do a review on. Definitely the filter can tell a story when things are starting to go sideways, but it would be a sickening feeling to cut it open and be faced with an ugly mess like that and be running a magnet through the pleats and the oil on the dirty side of the filter and see all the fines sticking to the magnet.    The dealer may have some ideas based on experience as to where that coolant smell is coming from, I would imagine if they can't find it but its smelling they would put dye in it to they could give it a run cycle and use the black light to see where it pops up, if its a hose connection, water pump, rad or even a head gasket etc. 
    • riddler
      Torsion adjustment

      By riddler · Posted

      Good looking truck, suspensionmaxx looks like a solid option
    • riddler
      Torsion adjustment

      By riddler · Posted

      Thanks for the info, im considering a leveling kit or 4" lift kit.
    • davester
      frustrating P0446 code

      By davester · Posted

      charm.li (website) has the vehicle-specific diagnostic procedure for that code, you can use to find what the cause of it is.
    • KARNUT
      Oil Consumption

      By KARNUT · Posted

      It’s at the point of amusement. I’m retired I have time. It’s fun seeing people try to convince me I’m using oil. I’m buying oil at the prescribed time. It gets drained and new goes in. Do I add in between, no. My oil doesn’t even get dirty in 5k miles. I don’t even see any drop on the stick. I check in the same place. All is well.

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...