I'll try to keep it short:
I have an 03 5AT sedan with 77k miles. A couple months ago I did a few drain and fills with J-mastic fluid and shortly after my tranny started slipping under light throttle. It has been getting worse so this morning I went and got a full system flush with J-matic at the dealership (10.875 qts). Unfortunately the full flush didn’t help so I am assuming something might be wrong with the tranny? The car seems to slip easily in 5th gear so if I drive it in manual mode and keep it at 4th it drives fine. However if I shift into 5th or put it in Drive it slips as soon as it gets into 5th.
Reading through the forum I haven't found anyone who has had major problems with their transmission? It seems like these transmissions are pretty bullet proof which is why I really want to believe that there is some other problem I am not seeing.. Does anyone have any suggestions? I would really appreciate any help or advice.

P.S. My goal is to ultimately sell it so if anyone thinks they can fix it easily I will give you a good deal. (I owe about $16,000 and I would like to try and break even). It is pearl white and it has the premium package with Tan leather, power everything, Navigation, Bose 6 disk in dash player, chrome rims, spoiler, gold trim...)

 

Sounds like the clutch linings are coated with varnish from insufficient maint. or the valve body is malfunctioning for some reason.

"*DO AT YOUR OWN RISK*
You just did a full flush, but since you are at the end of your rope, add one pint of Berrymans Transmission cleaner and seal conditioner--run it easy for a week, re-drain and refill with new fluid. What you are trying to do is clean off the clutches, clean out the valve body, and renew the friction modifier additive. *DO AT YOUR OWN RISK*"

If that works well enough to stop the slipping and get the car sold, great. If not, then you're looking at tearing into the thing to find out what the hell. Either that, or just trade the thing in for something else for close to the same as what you owe. It will be a step down, but a least you will have a warrantee.

These modern AT's are no joke. When they say use ONLY a particular type, they mean it. I suspect somebody may have added a low Cf fluid and prematurely wore out your clutches if the Berryman's clean out doesnt help.

 

Sealed for life guarantees a short life................77k is very late for a first fluid replacement, pan drop and clean.

Start with 30k and evaluate the future intervals from the residue you find then.

What did dealer quote for a reman replacement .......$5,000?
The wholesale price on the old 4 speeds was $1800, the extra gear adds $1000.................and people want 6-7 speed AT now............that will come as a real repair shock, when a tranny costs $1000 per forward gear to change.

 

I bought the car with 50k miles and was told that all maintenance was done at the dealership... I didn't have any problems until about 1 week after my first drain and fill (at about 73k miles).
It drives fine in 1st through 4th gear but if you let it go into overdrive it slips right away.
I'm going to trade it in this weekend and probably get an 05 G35. I will be losing a couple thousand because of what I owe but its worth it to not have to deal with it any more...

 

I dont think I have any other options so I am going to try out the Berryman's.

Also... if anyone wants to take this project on themselves I am willing to sell for less than I owe and take a loss. At this point my bottom line would be $14,250 so if anyone can jump on this let me know. If not I am going to trade it in and wrap my negative equity into another car....