4l80e 1995 c2500 2wd

[gary I THINK I CAN FIX IT]

hi everyone, got this truck to pull camper, it wasnt running runs now but when it shifts out of 1st gear it bucks and stalls. any ideas and if i need a different trans what will fit for that year. thanks in advance for any input.

 

[Will L.]

Welcome.
What engine and because of the odd nature, if you do a Youtube video and post a link here that hat might help.

Do you have a way to jack up and set on some quality jack stands? Take the wheels off and place them under the rear frame, and see if it will go through the gears without the load of the truck on it. Idea of removing wheels is just for added safety incase it comes off stands. If you can do it where there is room to drive away at 25 mph then leave the wheels on.

Please put the truck info in your signature line also. That way it’s always there for future posts and we dont have to ask what details are.

 

[gary I THINK I CAN FIX IT]

thanks Will L, I will try that. its a 5.7

 

[gary I THINK I CAN FIX IT]

ok, I put it on stands and it will shift without stalling till you hit the brakes then stall and dies. Iam thinking its the converter or tcc switch has gone bad

 

[Will L.]

Thats what it sounds like to me.
Need to get a scanner/ computer on there to see what is happening at this point.

 

[gary I THINK I CAN FIX IT]

thanks for your help. i will repost when i get it figure out

 

[WarWagon]

Check the brake switch is working properly. Known weak point on our trucks.

 

[gary I THINK I CAN FIX IT]

warwagon that will screw with the trans?

 

[ak diesel driver]

at minimum it will keep the torque convertor from locking up

 

[Will L.]

But regardless of brake switch- the tc should not stay locked up and cause engine fail. The tc is not allowing disengagement and if engine rpm being maintained by trans input shaft speed- if brake switch is stuck on- tc should never lock. If brake switch never comes on- that shouldn’t keep it locked up- would it? I feel like I am missing something here. Kinda distracted, but still not seeing it.

 

[ak diesel driver]

my understanding is everything pretty much defaults to torque convertor unlock

 

[Will L.]

Yes, I agree. Thats why I cant see a defective brake switch causing the issue.
However if a scanner/ computer is hooked up, a command from brake switch to tcc would tell it.
It would tell if anything is called for it to be locked up. If its all good and nothing is called for, and line pressure is in range- then I would say defective tc.

 

[MrMarty51]

Had that happen on a fresh reman 700R4 in a 87 K1500. Trans shop mailed me over pan gasket, fluid, solenoid and trans internal wire harness.
They had me switch out those components and worked good as new.
I’m sure the TCC solenoid would have fixacated it.
Oh yeah, they also sent a check for $125.00 for me rolling in tje snowbank to get it all accomplished.
Welcome to the forum.

 

[gary I THINK I CAN FIX IT]

ok. thanks for the info.

 

[gary I THINK I CAN FIX IT]

ok guys i put in different trans same results.

 

[Will L.]

Ok, Score is truck 1, parts cannon 0.
Now get a scanner on there.

 

[gary I THINK I CAN FIX IT]

I have the update. vss buffer was bad. i unplugged it and it seems to be fine now just no speedo. thanks for the help

 

[MrMarty51]

Thank You for posting the fix.

 

[Stoney]

Ok gotta ask...what the heck is a VSS. Vehicle speed sensor?

 

[EWC]

Yes