HELP!-(how many times do you see that one) Tranny Problems

[big blue]

Tranny guru's I am in need of your wisdom

I was driving my wife's '03 Mustang GT Auto and everytime I approach the shift in a slower than average acceleration of 4th gear the whole car shudders and slips into gear. Yet under normal or moderate acceleration (for me) it slips into gear without incident as well as getting up to speed with O/D off then turrning it on. This is the first time anything like this has happened and we have only had this car a couple of months and with 20k on the odometer I am hesitant about getting the tranny flushed or even looked at without getting ripped off. any suggestions please help.

 

[8yourZ06]

From what Ive read on the 4R70W(tranny in your car), the design of it has something to do with it. When the transmission is getting ready to shift, pressure is applied to the stopping of the last gear as well as pressure to engage next gear at the same time. In other words the line pressure is split between the two and doesn't allow enougn pressure to fully engage the next gear. Many times this transmission will "neutral" between the 3-4 shift. I have experienced this on my 01 GT on occasion when I first got it. It seemed to get better with miles and didn't happen enough to take it to the dealer just every once in awhile it would do this. I now have programming and have boosted line pressure moderately so the shifts are quicker and firmer than stock but not maximum. I would recommend a tuning, J-mod or a shift kit and a tranny fluid change. The factory ATF is only semi-synthetic. Mobil 1, Redline, Amsoil would be some good choices.

 

[big blue]

thanks for your advice 8yourZ06 I don't know if a shift kit is in my future but there will be a replacement of tranny fluid with full synthetic

 

[BlackMagic]

i had a problem with my 98 gt going into overdrive while in traffic. a ford tech told me it was the tq converter and to add some friction modifier. we added it, went for another drive, and the shudder was gone. so my suggestion is to get some friction modifier and try it, was only like 4 or 5 dollars.

 

[Red03Mustang]

I have a similar if not the same problem you are experiencing with my '03 GT auto. I have no idea what this friction modifier is you are talking about - could you enlighten me about it? I'd definitely like to do something with it if it fixed your problem. Could you explain what I'd need to do with it?

Thanks!

 

[8yourZ06]

thanks for your advice 8yourZ06 I don't know if a shift kit is in my future but there will be a replacement of tranny fluid with full synthetic

Glad I could be of help.

 

[8yourZ06]

I have a similar if not the same problem you are experiencing with my '03 GT auto. I have no idea what this friction modifier is you are talking about - could you enlighten me about it? I'd definitely like to do something with it if it fixed your problem. Could you explain what I'd need to do with it?

Thanks!

Friction modifier is a additive in the ATF that allows your clutches and bands to opperate without slipping indeffinately. There probably is different amounts of friction additive depending on what ATF you choose. Baumann (if its spelled right) Engineering did a book on Ford auto trannies and from what they say most of the problems are related to a lack of line pressure. Ford does this so is shifts smoothly. Since putting Mobil 1 in my trans. its quieter and shifts better. The factory fill is crap.

 

[narongc73]

Tranny guru's I am in need of your wisdom

I was driving my wife's '03 Mustang GT Auto and everytime I approach the shift in a slower than average acceleration of 4th gear the whole car shudders and slips into gear. Yet under normal or moderate acceleration (for me) it slips into gear without incident as well as getting up to speed with O/D off then turrning it on. This is the first time anything like this has happened and we have only had this car a couple of months and with 20k on the odometer I am hesitant about getting the tranny flushed or even looked at without getting ripped off. any suggestions please help.

Did you change the transmission fluid by any chance? It's suppose to get Mercon V which should fix the shudder. Mercon III will not do and might require a friction modifier. If it's factory fluid it should still be Mercon V and you do not need a friction modifier unless it doesn't have mercon V in there. At this point a shift kit might kill your tranny. Try changing all the tranny fluid with fresh mercon V. If it doesn't work your tranny is probably dying. And who knows a shift kit at that point might fix it. Also get a tranny cooler.