Automatic transmission problems

Discussion in 'SN95 4.6L Mustang Tech' started by 94DanStang, Jan 16, 2004.

  1. Wondering if you folks can help me with a little issue? I've got a 2001 GT vert with 41500 miles on it. I bought it about 4 months ago with around 38000 miles. A few days ago, the transmission (an automatic), started shuddering and clunking when it would shift into OD. I seemed to be OK if I drove it hard, but driving easy, it would clunk. I took it to a couple of places and they suggested changing the torque-converter. I finally took it to Ford and they suggested changing the fluid and adding some sort of friction modifier. I opted for that and it seems to have fixed the problem for now.

    Anyway, now for the problems. I am very concerned that this trans is going to cost me a fortune (I have a 94 GT vert also, and had the trans rebuilt no less than 3 times). Also, I cannot FATHOM that a car with 41000 miles needs a torque convertor. Finally, the car seems to shift like a dog now. Kind of sluggish and boring to drive. Overdrive - I hate it!

    Anyone have any ideas on what the deal is? Is this a common problem with these cars? Thanks for the help and comments.

  2. Welcome to the club!!!!!!!!!!
    i ve been trying to figure out what s the problem also. I have a 2001 Gt.
    By changing the fluid and adding a friction modifier, they just applied one of their TSB that was issued in the mid 90s. But for some reason that TSB was removed in 1998, the problem still there though.
    I can find some infos in about that problem and some of the solutions is changing fluid with Mercon V, tranny cooler and some kind of adjustment.

    What do you mean by it shift like a dog??
    sorry i'm french canadian lolllllllll

    You can also have a look on modular depot, i asked the same question and having good feedback :nice:
    Cobra42898 likes this.
  3. hope you didn't overfill the fluid. that can cause a sluggish effect
  4. 94DanStang:

    "speed545" is right about the "Transmissions 101" articles (Tech Articles/Transmissions section of There you will find how to do the "jerry mod": much quicker shifts by modifying the separator plate only. The trans is pretty solid but the OD band is the weakest link. WOT 3-4 shifts (i.e.--leaving OD on and stomping the gas) can cause premature death of the band. Transmissions 101 will explain all.

    For the immediate problem, a complete draining of the trans (including torque converter), new filter, and fresh Mercon V should make things much better. Add an auxillary cooler to reduce heat and your transmission should last a long time.

    speed545: "... like a dog" means it is very slow/sluggish. The j-mod will sharpen up the shifts so that the transmission will shift like a pit bull! Keep warm up north.
  5. DanStang94:

    Sorry, re-read your post and see that you have changed fluid recently. But, what is this about adding a friction modifier with Mercon V?? It is my understanding that the only thing that is supposed to go in the fill hole is Mercon V. Can you provide specifics, please?

  6. Hey thx a lot nyuk98gt. I just ordered B&M tranny cooler. Car is going in in april for another TSB on 4R70W ( clunk noise on downshift 2nd to 1st ). I ll have them swap the oil in the tranny, install the cooler at the same time. I might save a little on labor. I have a Hypertech III and i selected firmness shift point on the tranny. Only effective at WOT thought.

    Thx again guys for precises answers :nice:
  7. The automatic transmissions on the Mustang GT are really problematic. There is a large post here on this website about other people who own the Gt who are also having problems with their transmissions. Try to find it and read it. Also, I think that you made a BIG mistake by buying an automatic transmission in a Mustang GT. A manual 5 speed transmission would have been a better choice. They last longer and have less problems than the automatics.
  8. Whatever Ron :notnice:
    It's funny when anyone with an automatic is having problems someone chimes in how they made a bad choice and should have gotten a 5-speed :bang:
  9. In the 2+ years I've been reading stangnet, this is the most ridiculous comment I've ever witnessed.
  10. My 02 did the same but today, I took it in for its 30thou service...........O GOD ITS SOOOOO SMOOTH NOW! I had it all done, injectors cleaned, new fuel filter, tranny flush.

    The tranny fluid was brown......ugh
  11. Hey man. I say it the way it is. Lots of people who own Mustang GT's feel that an automatic is not suitable and that the automatic is a problematic transmission. Less people who own 5 speeds have these transmission problems than the ones who own automatics. My comment was not intended to offend anyone in here. But the truth is that automatics have more problems than 5 speed manuals.
  12. I agree your car should only have Mercon V in it. If the car is shuddering, it needs a fresh change of fluid (drained TC AND pan/new filter), as well as an additional transmission cooler like B&M sells. I don't know the mileage/fluid change history/fluid condition, but that's the solution to the problem. And yes, if the above doesnt work and you still have TC shudder then you should replace the TC. If you want a shift kit, ditch the hypertech, go to and get the J-mod. You can't beat a kit that was designed by one of Ford's Transmission Engineers, period. I've done 8 of them on a variety of vehicles, they really arent that hard.

    If an AODE/4R70W is rebuilt properly it will withstand about 600RWHP. It's been done already. If a rebuilt isn't working, then whoever the mechanic was doesn't know what theyre doing. Were the radiator cooler and lines ever flushed out on those installations? As far as the 5 speeds being a better choice, it's up in the air. 5 speeds are more efficent, but is there a 24 page sticky in this forum about problems with which tranny? The 5 speed. So saying they're more reliable is pretty funny.
  13. Thanks everyone for the replies. BTW Ron - stop and go traffic in Atlanta with a stick sounds like the 9th level of Hell. I'll take the auto. :D

    Anyway, I don't know about the fricton stuff. They said Mercon V and some 'friction modifier' per a TSB. It's anyones guess.

    I'll check out and give it a read. I was also thinking about a cooler.

    The slow and sluggish is wierd. Before the fluid change, it felt a little crisper. It wouldn't drop into OD at the worst times - going around curves, etc. Now, it seems like all it wants to do is run in OD. What do you fellas recommend about OD? Do you use it around town? What speed do you let shift into OD? When I drive with OD off, it always feels like I am doing something bad, like I'm gonna burn out 3rd or something.

    Thanks again for the feedback.
  14. driving with the OD locked out wont cause problems, it just causes the EEC to disable the extra gear. 4th gear is the weakest one because it's created by applying the band. The bands last a long time unless they're abused (WOT 3-4 shifts, etc) I turn my OD off in town because i find it annoying when it shifts up and down so much at the stoplights. If I'm cruising over 45 i usually turn it back on.
  15. Don't overlook the tranny mount. I had "clanking" in my last auto stang when engaging the gear until I had it changed out. It's like a crossmember for the tranny made of metal and rubber. Leaking fluid can dissolve the rubber. I believe it was about $40 from the dealer. And if you've got leaking check/change the rear seal while you're at it.
  16. been having the same prob and prayin that I dont need a rebuild. a little comforting to see its common though. guess i'll just be getting a tranny tuneup as that seemed to help you guys.
  17. Absolutely. I also suffered at the hands of the dreaded tranny shudder, changed out the fluid, and 3k+ miles later I'm still shudder free.
  18. a programmer may help with the shifts and you could increase timing as well.
  19. Yes, the computer program can also be changed to help in this area, but it won't do as much on the newer cars. 94-5s would benefit most by this, 96-98 some, and probably not much on the 99+ cars.
  20. Dan......AHMEN........Hell I don't even wana drive my auto in Atlanta traffic.....I wana helicopter :)