Vetal

iTrader: (3)

I had alternator failure and that caused most of my clutches and steels to burn completely. Had my 4L80E rebuilt by a shop but since then I can't get my TCC to lock when commanded, even manually applying ground to TCC wire doesn't make it lock. Before the transmission was pulled out, TC was locking properly.
I'm a little desperate at this moment since shop who did the rebuilt has no idea. I've checked TCC solenoid with pan off and it clicks. I wanted to get the lockup valve out of the pump (through the pan), but it doesn't want to come out after locking ring removed
What else can I check? Is there any way to remove lockup valve out of the pump?


Here's the video of the lockup valve moving but not coming out:

LLLosingit

iTrader: (4)

How exactly does a bad alternator cause you to burn up a transmission?

Vetal

iTrader: (3)

Because of low voltage in the system solenoids presumably provided less pressure to the clutches allowing them to slip under full power

LLLosingit

iTrader: (4)

Hmmm... I was always under the impression that if the voltage is to low that the trans goes into limp mode. I could be wrong though.
Did you also get the converter flushed before you reused it?

Vetal

iTrader: (3)

Yes, I got it flushed (with petrol, as far as I remember)

built408

iTrader: (10)

Alternator did not cause your issue.

Ratdaddy60

[QUOTE=built408;19236780]Alternator did not cause your issue.[/QUO
Low voltage causes max line pressure.

Vetal

iTrader: (3)

Alternator died, and the next couple of runs transmission started slipping.

jakeshoe

iTrader: (14)

Low voltage can cause transmission failure.

jakeshoe

iTrader: (14)

[QUOTE=Ratdaddy60;19237038]It also causes other issues. Voltage doesn't just run the EPC, and on a unit with fixed line pressure, the EPC is irrelevant anyway.

Ratdaddy60

[QUOTE=jakeshoe;19237151]A bad ground in the TCU might cause transmission damage over an extended period of time. Ok, so a unit with fixed line pressure wouldn't be effected by low voltage. The shift solenoids either work or don't.

Ratdaddy60

Use a small drill and drill into but not all the way through the aluminum plug. Screw a small sheet metal screw into the plug then you can use a pair of pliers to remove the plug.

jakeshoe

iTrader: (14)

[QUOTE=Ratdaddy60;19237476]I've probably built more transmissions than anybody posting in this forum.
4L80Es specifically.
So let me break it down simply for you.
What happens to the shift solenoids when they lose voltage slowly, as in a battery that is constantly losing voltage throughout a run, while the fuel pump, OK injectors, and coils are drawing on it?

Ruler_Mark

Can confirm the 4l80e is not happy in 3rd when you run out of volts. Stopped us from breaking into the 8s last year.

Side note jake can double confirm cause he had "fun" dealing with the trans smellzzz

Vetal

iTrader: (3)

My transmission completely burnt 2nd gear clutches IIRC.
Anyway, any advices what to do next? Shops says "cut the converter", but I don't believe it's TC not locking...

Vetal

iTrader: (3)

Do you mean I should drill into the lockup valve to remove it??

Ruler_Mark

Cooler always has to be flushed and converter cut when debris enters the system. Stuff can stay trapped ez in the converter

Hi-Po

iTrader: (4)

Just so I understand better... on a stage 5 build where the line pressure is a fixed value, will a weak/dying alternator hurt the transmission?

Sorry OP, I'm no help here.

jakeshoe

iTrader: (14)

Yes it is possible under certain circumstances.
It's not a problem caused by pressure control.

Hi-Po

iTrader: (4)

Thanks Jake. Just trying to not call you with a problem, ever lol.