Transmission help

Motodox · April 19, 2015

Hello I have a 2000 Silverado z71 with a 5.3l vortec I just purchased the truck and it has 200k high miles. The truck was shifting perfect and now it's shifting really hard from first to second and I need to get on top of this . Has anyone ran into this and found a solution or am I just going to need to pull the tranny and have it rebuilt at my local tranny shop? I was hoping it would be something I could just fix, what are my first steps to find the problem?

What weird is it don't shift hard until everything has really warmed up. And tranny gets up to temp after driving for 15mins or so.

The tranny oil is no where near clean and has maybe a hint of red tint, but looks mostly dirty.

What should I do!?

gmtech4 · April 19, 2015

They do shift hard on some 60s, now aside from the drivability that hard shift creates , it also creates no wear on the clutch packs as its not sliding into gear.

I say that because I pounded the guts out of my old 700R4 and when I took it out (crushed the body)and apart , it was brand new inside , it was a gm rebuilt tranny and I put 200K km on it

If the oil is shitty then you may have a concern as you know nothing of its history ,

Changing the oil DOES NOT repair any mechanical problems inside

Motodox · April 19, 2015

Ok yeah I have everything to do the change but like you just it prol be a waste of time. I smelled the tranny oil and it's doesn't smell burnt and it's not the worse I've seen it's a littler redder then I thought but it's defiantly not clean.

I just drove he truck and it shifted perfectly smooth and all. Seems it only starts shifting hard when it's hot and I'm pulling my boat or bike in the back.

Am I looking at a rebuild or what?

And any parts I should look at or inspect possibly change?

Anyone experienced this 4l60e problem what was the solution?

Thanks everyone

Motodox · April 19, 2015

Could it be a worn tcc regulator valve ? I don't have any check engine lights on and it's seems to only shift hard first to second.

gmtech4 · April 20, 2015

What has the tcc have to do with a 1-2 shift ?

Stop this and either get it rebuilt or drive it till it pukes guts

Motodox · April 21, 2015

Took to a tranny shop to have the truck scanned, one trouble code showed which was code 1870 which is internal slippage from the tcc regulator valve wearing out its bore and causing the converter clutch to slip. The computer recognizes this so it throws the code and max's out the electronic pressure control which is why it shifts hard.

gmtech4 · April 22, 2015

Took to a tranny shop to have the truck scanned, one trouble code showed which was code 1870 which is internal slippage from the tcc regulator valve wearing out its bore and causing the converter clutch to slip. The computer recognizes this so it throws the code and max's out the electronic pressure control which is why it shifts hard.

Makes sense , I've been out of tranny work awhile lol