Just started yesterday. When accelerating up to highway speed I experience what I can only describe as a violent, momentary downshift at about 53-55 mph. It actually squawks/chirps the tires for just a split second, then it's fine.

If I stay at 60-65mph, you'd never know anything is wrong. If I slow below 45 or so, I'll experience it again -- just one time, for a split second, consistently at about 53-55 mph, as I accelerate back up to cruising speed.

If I stay at or below 50mph, as when just tooling around town on errands, I never experience the problem.

I assume it's when the final shift into top gear is taking place, but I can't be sure.

Anyone ever experienced or heard of this? Any thoughts on what the root cause might be? The interior workings of automatic transmissions are like black magic to me. Totally incomprehensible.

Whatever it is will eventually destroy your trans, if not the rear-end or driveline from the lashing... do you have superchips?

sounds like there is a stacked shift.. but incase you aren't using aftermarket trans tuning, the first thing I would do is check the trans fluid, level and color... if they are ok then i might check for codes incase there's a stored code or something. having the dealer, or a transmission shop start a "quick learn" might reset the stock trans tune, but before doing that it may be better to disconnect your battery for bout 10-20 minutes and drive again.

I'm not too sure how the transmissions work either, but if the above things fail, or any other cheap/free thing that anyone else suggests fail, it would be a good idea to take it to the shop.

perhaps if the clutch plates inside are worn so thin it could be jumping on a lower gear before finding the higher one.. but like i said I really don't know the mechanics of our autos. I do know they have no bands though, only clutches.

That is a new one. Definitely start checking that thing out before serious damage is done.

Brand, what year is your truck again?

Mine is a 2005, with the 545RFE.

My problem sounds a LOT like this:

https://dodgeforum.com/forum/1st-gen...-03-rango.html

I've reset the computer by disconnecting both battery cables for several hours; and I've had a fluid/filter service performed (both filters, genuine Mopar).

The problem still persists, though it is less severe and has moved up a few mph to between 55-60.

No codes are present.

Next stop is the dealer, I suppose. Unless anyone has any additional thoughts.

I can't think of any, I hope for you it's as simple as re-indexing the shift points like that other thread and gets you out the door less than $100 lighter.

Well I will start asking the simple questions

How many miles?
When was the last fluid change?
When was the last filter change?
When was the last time you checked the fluid level?

Most people, but not all have had issues because the fluid was not changed, or the filters.

Also if the fluid is not correct this transmission will go on the fritz, to much is better than to little.