2015 Explorer - Delayed shift 3-4 gear

[lucky644]

I have an issue that just popped up: under average acceleration (not WOT), the car doesn't want to shift from 3rd into 4th; the RPMS gets up to 5000+ before it finally does, feels pretty delayed.

The rest of the shifting feels normal.

The last work the car has had done on it was spark plugs replaced, evap purge replaced, and the pcv replaced.

Any ideas on how to troubleshoot this?

The car has 223,000KM/138,000MI on it.

 

[texsn95]

When (if ever) was any of the tranny fluid drained? If you don't know, I'd start there with Mercon LV only, search for the 3 x 3 method.

 

[lucky644]

When (if ever) was any of the tranny fluid drained? If you don't know, I'd start there with Mercon LV only, search for the 3 x 3 method.

I'm not sure; we bought it used. It went to a mechanic who did a full inspection and they said the transmission fluid was still good.

So other than the word of the mechanic, it's unclear if its still good, or if its ever been done.

 

[peterk9]

If you are not sure, it would be a good thing to do anyway so you will know it's been done. Then if that doesn't resolve the issue, you can dig deeper into it.

Peter