Tranny wont go to 3rd when it's warmed up

[kingjoop]

We are having a little trouble with a 727 tranny when it's getting warm.

From a cold start the tranny works great, it has a manuel valve body and console shifter. No trouble at al... but when we keep driving and the car is getting warmed up it wont go to 3rd gear anymore. 

Someone knows what this could be? Thanks! 

[RD]

does it just rev up without movement or stay in 2nd gear?

[kingjoop]

it stays in second gear... 

[lisiecki1]

stuck valve in the valve body once everything expands from the heat maybe?  or a slipping band when the trans fluid gets warm and thins out?

how many miles on the trans and valve body?

How does the fluid look/smell on the dipstick?

Any additives in the trans fluid?

[elacruze]

Could be as simple as a loose valve body, leaks when expanded. Could be cracked. Could be worn clutches, could be a worn pump.
Could be a worn governor or spool.

How long have you noticed it, how quickly did it come on?

[kingjoop]

stuck valve in the valve body once everything expands from the heat maybe?  or a slipping band when the trans fluid gets warm and thins out?

how many miles on the trans and valve body?

How does the fluid look/smell on the dipstick?

Any additives in the trans fluid?

the tranny was recently rebuild (according to the previous owner), let's say a few 1000 miles on it...

fluid looks and smell great.. oil that comes out looks brand new.. filter is clean to..

Not sure what you mean with your last line, never had english @ school (i'm Dutch)

How long have you noticed it, how quickly did it come on?

pretty quick.. was on the road when it started.. first a few shifts for/back-ward did the job till home.. since then always when the tranny gets warmed-up  

[elacruze]

Starting to sound like a check ball not seating well, maybe a little dirt. If 1 and 2 gear are firm even when hot, more likely that 3 gear circuit has a problem. Low pressure from leaks cracks or pump would likely show up in 1-2 also. I'll step aside and let the auto trans gurus take it from here, that's about the end of my knowledge.

If I was at home alone, I'd take the pan off and degrease the valve body best I could, but I'd probably take the wrong thing loose and lose a ball or spring. 

[John_Kunkel]

Since it has a manual VB I doubt if that's the problem because there isn't much to go wrong in a manual.

Since it relates to temperature and the fluid gets thinner with temperature there is probably excessive leakage somewhere in the front clutch, the thicker cold fluid won't leak at the same rate that the thinner warm fluid will.

The front clutch is used for both 3rd gear and Reverse, how is Reverse if you give it hard throttle when warmed up?

[kingjoop]

Reverse works ok, when it's in Reverse and you put your feet down it starts spinning the wheels..

[John_Kunkel]

It could still be a front clutch problem because the line pressure triples in Reverse.