05 48re won't upshift to o/d at times

[DPKetchum]

05 dually,48re 3. 73 geared 4x4. At times on long trip pulling 8k or so won't upshift to o/d unless foot removed from throttle. Dosen't matter even if downhill or tow/haul on or off. As soon as it downshifts it holds third until foot packed off throttle no matter how fast or distance. After a while works correctly. been doing this intermittantly for 30k plus etc. Trans has been serviced on a regular basis and no codes etc. Any thoughts?

 

[SP Diesel]

It sounds to me like you torque converter is starting to go out and slipping more then it should. A new torque converter and a transmission controller that holds TC lockup in 3rd gear would help you alot.

 

[ArmstrongB]

I have an 06 mega that does the EXACT same thing and it only has 7K on it. Just started doing it about 2 weeks ago on the way to the lake.

 

[DPKetchum]

What about valve body solonoids? Owner thinks a comuter glitch. I don't think so. AS I stated been doing this a LONG time.

 

[JCBerry]

Mine did the same thing, dealer replaced solenoids then converter, it kept getting worse and worse. Finally traded it in after numerous trips to dealers, DC rep wouldn't do anything, he kept telling me it was normal. Good luck with your problem I couldn't wait for those IDIOTS any more I needed the truck not excuses.

 

[the whale dog]

I have an06 and towed my bckhoe home with it at 55 on cruise it was all honky dory at 60 it would not shift called my mechanic at the dealer and he advised me of a flash for the computer there had already been 2 revisions and the truck did not have 1000 miles on it they upgraded 3 programs in the computer shifts better on the run and I am still trying to get used to having to run 2500 rpm to get up a hill I used to idle up with my 6 spd check out the flash it was a noticable improvement