Overdrive doesn't work when warm

[Red kappa]

Ok I'm new on here but I just bought a 1998 Tahoe with the 5.7 and 4x4 well when it is cold the transmission shifts great but when the fluid warms up only 1st and 2nd gear work. If you have it in o/d and it goes to shift into 3rd it just revs up like it is in natural but you put it down in 3 and it comes back but is still running in 2nd any help would be great thanks

 

[Goodinblack]

Maybe valve body issues

 

[Red kappa]

I know I just got off of the phone with a buddy of mine and he was thinking many the 3rd and 4th gear silanoid

 

[SunlitComet]

there is a solenoid a and b. no 3 and 4. your description sound more like the 3-4 clutch assembly is not working correctly.

 

[Red kappa]

What fix would you say would be best on that

 

[SunlitComet]

if, it is the 3-4 clutch the transmission needs to be dismantled and an overhaul is in order as you already would have it in pieces. this is assuming the clutch material is wasted.

 

[Goodinblack]

Drop the pan and see what's inside

 

[NathanJax]

your description sound more like the 3-4 clutch assembly is not working correctly.

if, it is the 3-4 clutch the transmission needs to be dismantled and an overhaul is in order as you already would have it in pieces. this is assuming the clutch material is wasted.

 

[Red kappa]

But if it was the valve body wouldn't it have problems hot or cold?

 

[SunlitComet]

not necessary.
As a tranny gets hot the viscosity of fluid changes a tad bit and clearances can have minor changes that can effect components. those changes can also effect whether or not a cracked apply piston for the clutch is doing the damage.