8 speed suddenly went out. No forward or reverse gears

[flyingfool]

I would contact a professional transmission builder, they know what the good parts are and where to get them. do your own due diligence..

[kgkern01]

21 minutes ago, flyingfool said:

I would contact a professional transmission builder, they know what the good parts are and where to get them. do your own due diligence..

Isn’t that part of the purpose of car/truck forums, so that people can share their experiences and advice with others?  

[flyingfool]

after awhile we get tired of helping others who dont bring anything to the table.. kinda like a relationship, participate or GTFO.. alot of time the answer has been given over 100 times and no one response to those who dont search

Edited November 29, 2020 by flyingfool

[kgkern01]

1 hour ago, flyingfool said:

after awhile we get tired of helping others who dont bring anything to the table.. kinda like a relationship, participate or GTFO.. alot of time the answer has been given over 100 times and no one response to those who dont search

That’s why I made this post, I’ve searched for posts with others who lost forward and reverse suddenly in their 8-speed with no overheating issues and didn’t find any.  So I wanted to see if anyone else had encountered the same or similar issue and maybe not posted about it.  Before I started getting the delayed engagement and hard 1-2 shift happening on the trans about a year and half ago, I had no issues with the 8-speed and it shifted great.  That’s why I’m assuming this may be related?

[flyingfool]

i would try the popular Camaro Forums it might have more members that have done the research already on 8-10 speed upgrades repairs etc.. those guys might be more performance and hands on than most members here

[M1ck3y]

Can someone else chime in? Did that go right over his head or am I missing something?

[Chad2815]

Same guy gave us all grief for trying to get the dealer to fix our clunky leafs and then makes a post asking about part numbers when he takes his to the dealer for...............you guessed it clunking leafs. As far as the 8 speeds, thats the first I have heard of complete failure like that, maybe you can get some help from GM since they know these trannys have alot of known issues. 

[kgkern01]

56 minutes ago, Chad2815 said:

Same guy gave us all grief for trying to get the dealer to fix our clunky leafs and then makes a post asking about part numbers when he takes his to the dealer for...............you guessed it clunking leafs. As far as the 8 speeds, thats the first I have heard of complete failure like that, maybe you can get some help from GM since they know these trannys have alot of known issues. 

I hope so, I can’t find a lot of info I n complete failures on these 8L90’s either, especially on a basically stock engine.  Talked to the dealership today, it’s going on their rack tomorrow, so I’ll find out the verdict then.

[JimCost2014]

On 12/1/2020 at 7:34 PM, kgkern01 said:

I hope so, I can’t find a lot of info I n complete failures on these 8L90’s either, especially on a basically stock engine.  Talked to the dealership today, it’s going on their rack tomorrow, so I’ll find out the verdict then.

Update?

[kgkern01]

11 minutes ago, JimCost2014 said:

Update?

They were supposed to put it on the rack Wed, I drove by Thurs morning and it wasn’t outside anymore, however I haven’t heard back yet.  So hopefully on Monday.

[JimCost2014]

3 minutes ago, kgkern01 said:

They were supposed to put it on the rack Wed, I drove by Thurs morning and it wasn’t outside anymore, however I haven’t heard back yet.  So hopefully on Monday.

Stop in, say you forgot something in the center console, and need to get in the truck.

Just so you know what is going on, could be good, maybe bad, saw way too many parts on the ground when I saw my 16 with the engine coming out.

[kgkern01]

So I finally have an update.  They said they pulled the pan and the fluid was black and burnt, even though I’ve never seen over 200* on the trans gauge, and it had the updated flush done last summer.  I asked them what failed, and they said they didn’t tear the transmission apart, based on the fluid and small debris in the pan,, they are replacing the transmission.  GM and the dealership is covering $1800 of the cost, I’m getting a new transmission from GM with 3yr/100k warranty.  I still have to pay $3800, but I can live with that amount for a brand new trans and 100k warranty on it.

[M1ck3y]

11 hours ago, kgkern01 said:

So I finally have an update.  They said they pulled the pan and the fluid was black and burnt, even though I’ve never seen over 200* on the trans gauge, and it had the updated flush done last summer.  I asked them what failed, and they said they didn’t tear the transmission apart, based on the fluid and small debris in the pan,, they are replacing the transmission.  GM and the dealership is covering $1800 of the cost, I’m getting a new transmission from GM with 3yr/100k warranty.  I still have to pay $3800, but I can live with that amount for a brand new trans and 100k warranty on it.

Could be worse. Glad it worked out alright for you

[kgkern01]

5 minutes ago, M1ck3y said:

Could be worse. Glad it worked out alright for you

This is true

[MDiaz]

On 11/26/2020 at 4:20 PM, mjm-1957 said:

You of course slid under there and made sure the shift cable and lever are still in one piece and attached I am assuming?

Hows it going bud i am havi.g similar issues on a 2019 silverado 5.3 8l90 do u have any suggetions

Went to store came back left running till it rurn off then stopped going forward or reverse 

It engages rolls forward like 1 inch at high rpm  same in reverse 

Scanned transmission comes up w pcs 5 low circuit

Chwcked lice data psi on 5 shows value 110