Delayed shift when AC is on

[axhoffman]

I have noticed recently that my truck takes a long time to shift, and seems to struggle from a complete stop to the next gear when the AC is on. My truck has a lot of miles, 216000 it is a 1999. Not sure if this is transmission related or something else, since it does not have this problem when the AC i not on.

 

I appreciate any ideas.....

[07silver4x4]

My truck has a lot of miles, 2160000

lot of miles. Have you checked the ATF level/condition?

[muddkatt]

Is that a typo, 2.1 million miles?

[axhoffman]

lot of miles. Have you checked the ATF level/condition?

Sorry got excited with the 0's, levels are fine and I have changed the fluid

[axhoffman]

It takes a long time to shift the gear and I can hear like a fan making noise when this happens. Not sure what it is, like I said only happens when the AC is on

[07silver4x4]

I am no expert hopefully someone with more knowledge will chime in, but the AC could be putting higher load on the engine which might feel as transmission related. Are there any codes? When was the last time the AT filter was changed? I would also check the belts pulleys and tensioner.

[muddkatt]

Is the "fan noise" only when the truck is at operating temperature and been idling for over 5 minutes with the AC on?

[axhoffman]

No the fan noise is when I hit the gas and it is having a hard time shifting. I changed the fluid and filter maybe 6 or 8 months ago.

I also noticed than when this happens if I let go of the gas it shifts