2003 Yukon auto transmission issues?

[DT.IN.LB]

Hi All,
I am new to this site so let me thank you in advance for any info you can share with me.
I own a 2003 Yukon with a 5.3 I have started having problems it seems only when the automatic transmission is warm. kick it down to passing gear the tach comes up to about 3500 rpm and it acts like it wont go any where ( road speed stays the same ) so I let off the throttle just a bit and ease back into the throttle the vehicle speed increases but without passing gear. It does not show any codes what so ever. I have taken it to a mechanic and he thinks it might be a sensor but does not know what the problem is for sure because there is no codes.

Please help, getting frustrated as you might imagine.

 

[CEN2MENTAL95]

How many miles? How does fluid look color wise?

 

[DT.IN.LB]

The Yukon has 135, 000 miles and I recently serviced the trans and the fluid looked red and clean no smell very little on the magnet maybe less then 1/8 - 1/4 teaspoon

 

[big_b_in_PA]

Take it to a transmission shop, they can run the transmission independently and test each individual shift solenoids, it sounds like the 1-2,3-4 solenoid may be sticking, or possibly be bad. I could be wrong on the solenoid thing, but that sounds like whats going on.

Good luck!

 

[DT.IN.LB]

Take it to a transmission shop, they can run the transmission independently and test each individual shift solenoids, it sounds like the 1-2,3-4 solenoid may be sticking, or possibly be bad. I could be wrong on the solenoid thing, but that sounds like whats going on.

Good luck!

The problem is I live in Mexico and can't find a good trans shop to work on the problem, they all say if it shows a code I can fix it, any other ideas?

---------- Post added at 10:05 AM ---------- Previous post was at 09:30 AM ----------

Any chance this could be a Catalytic Converter issue?

 

[big_b_in_PA]

Dang, sorry about that. Dealer maybe, but other than that, I don't know what to tell you. If you can find a general mechanic that has done alot of transmission work, he might have a connection to a transmission vendor who will loan him a trans control unit. That was something I did in our shop a few years back. But that was also dealing with jasper engines and one of their units.

As for the cat converter, does it feel restricted when you are starting from a dead stop, like a traffic intersection? I think converters usually choke the engine out anywhere above 1500-2000 rpm. But don't quote me on that.

 

[DT.IN.LB]

Any chance this problem could be a fuel filter or pump issue?