I am hoping someone has experienced this before, and might have an answer
I had my transmission serviced yesterday at my mechanic, and since then it has been shifting pretty hard.
Short history:
He did the proper flush, but instead of putting in Mercon V, he put Dextron III, with an addative that was supposed to convert it to the required Mercon V. This is what this $30.00 CDN addattive was supposed to do. Anyway as soon as I drove off the lot, I noticed that the transmission was shifting pretty hard, especially from 1st to 2nd., but also in all the gears
I drove home, and took it back this morning to the shop (about 10KM), and he did another flush, this time adding Mercon V. Thing is, while the shifting shock has improved, it is still pretty bad from 1st to 2nd. I must admit that it is not so bad in the other gears now, and upshifts has improved.
He checked, and there is no codes in the system. He also reset the computer by disconnecting the battery for the required length of time.

Has anyone had this before?
Can anyone suggest a fix?
Was there not a thread sometime last year about an addative that improves the shifting?
I tried looking for the thread, but could not find

My mechanic asked my to use over the weekend, and see if shifting improves.

Thanks in advance for any suggestions

Well, the Windstar transmission should only take mercon V and not dexron III with additives, the dexron III should cause it to shift rough even with the additive but since the computer was reset by disconnecting the battery the transmission needs to relearn its shift patterns so the transmission will shift rough until it relearns your driving habits. Also, make sure the transmission fluid is all the way up to the hash mark on the dip stick even if it is a little above the FULL line it should be ok. But i would definately make sure that the people who serviced your transmission are aware that this problem occurred after they changed your fluid. But it should be fine in a few days of your driving the van and having the pcm learn your driving habits but if it is not fixed take it back and give them Sh*t.

It would be wise to find out how much of the Dexron-III was flushed out or how much Mercon V was actually put in. Also find out if your mechanic did an exchange or a purge thru system like the one discussed here by disconnecting the return hose into a bucket and adding fresh fluid while the old one comes out the return hose.

It would be just as bad if you ended up with mix of Dexron-III and Mercon V on the tranny. I know it would be near impossible to get rid of all the Dexron fluid, but you might need another flush to get rid of most of the Dexron fluid for the tranny to start working as it should.

Hi Ed

He did a full purge, and used 0ver 12 litres.
I trust him completely, as he has been servicing my vehicles for over 10 years, and this is the first time he has made a mistake where I have had to return for him to remedy. Hard to believe, eh???

I think you might be right though, in that he will have to do another purge to really get rid of all the dexron.
I'll see if there is any improvement today.

As a fellow Canadian (meaning I'm not immediately hoping on the sue bandwagon as some of my US friends would) I'd suggest you document all that's gone on. In spite of the fact this mechanic has serviced your vehicles for 10 years without fault I'd hate for a trans problem to occur and you be left with a 2 or 3k bill. If everything works out fine, great. I've had a couple of these types of situations and documenting the event has led me to a much less costly outcome. Without the paperwork I would have been sunk.

FWIW, my :2cents:

Piper

Just a quick update for those interested
Not surprising, there has been a slight improvement in the 1-2 shifting, and vast improvement in all the others since the oil was changed to Mercon V. Frustrating though, I cannot figure out why 1-2 shifting is still the same.
Thanks for the advice northern piper, and yes, I am keeping a record of all that has transpired. Tell me something, do you know where we can get Lube Guard here in Canada?
Is it available at the local CT store?

Has anyone had any experience with Lube Guard affecting shifting?
I plan to have my mechanic purge the tranny again on Monday, and would suggest he adds Lube Guard if there is a chance it might help.

Thanks again to those who responded

I would add only what is recommended by Ford ... MerconV. In particular, I prefer Mobil1 ATF.

I tried LubeGuard once on a failing transmission ... it continued to fail, perhaps more quickly, INS.