What is causing occasional slipping and or hard shifting in Transmission?

What makes a transmission slip usually is pump is bad not cerculating fluid to the bands or filter stopped up.Remedy,and additive would not hurt at this point i think i would try a bottle of lucas in it,it will help clear lines and filter,may help ,,

Pump indeed. It's an old car. Additives like Lucas - or Brake Fluid - will cause the Nitrite seals to soften and swell - for a while. Then it will turn the seals to mush - not right away - but it will. See about taking it to a Transmission shop and having it properly diagnosed. Expect to pay 1 hour labor for a proper diagnosis. The seals within the Transmission get old and hard over time. Honestly - there is no reason to change a Transmission filter - if there's debris in it - it's destroyed anyway. A complete fluid change between 60,000 and 100,000 miles - yes (14 to 16 quarts). One consideration is a remanufactured Transmission. Ford (and I'm sure some competitors too) have reman transmission for right around $1800 with a terrific parts and labor warranty. Sounds like a lot of money? It's only about 5 car payments of a new car.

Take the pan off again and look to see if there's a lot of metal shavings if so the tranny is on its way out if not try researching the shift solenoids or the tcc shift solenoid its called a torque converter clutch solenoid

Wad up three $100 bills and shove them down the filler tube - same effect.

Right. For all the parts I had to replace, I could have bought another car. I guess next time I buy a BMW or a Porsche.

I have the same car with the same exact problem! Did you ever find out what was wrong? I'd be curious to know because I've had a few mechanics look at mine and they can't seem to figure out what's causing it.

I guess I will try the Liqui Molly automatic transmission repair fluid when I get hold of it. Let's see what it does.

I agree with Tracy, I have a 2002 GT 4.6 and it has had some mods, I noticed that it had some weird stuff going on when I drove it normally, (so I never noticed anything for the first 3 years I owned it) but what happened was a strange shuttering feeling as it would shift into 2nd under normal operation, sometimes when it downshifted as well. I did a partial fluid change as recommended by the Ford maintenance online program I have that's made for Ford certified repair shops. It goes into detail showing possible reasons and remedies that are available as the problems arise and the info is uploaded to a cloud where it's shared with the network of other shops running the software. This is most likely cured by a simple partial fluid change. They state that only changing part of the fluid is necessary unless it's burnt really bad. Also it states to NOT use any synthetic fluids. Only vehicles Ford used synthetic were a few oddball Vans. I did this at 70k and my trsnny was like new, super smooth and quiet but will slam second so hard on upshift or downshift I need to be careful cuz it will break the tires loose an fishtail like crazy if your not ready for it. I used about 7 or 8 quartz, by just drropping the pan and cleaned off the magnet which had minimum shavings on it. I left the fluid in the torque converter and refilled through the filler, no need for new pan gasket if you didn't ruin the existing. The dealership will use a machine that connects between the radiator and the line in. They will run the car and they fluid is caught in a pan while the infeed tube is sucking in fresh fluid. They run it till the cycle is complete. This also leaves some old mixed in with the new. It is the closest you can get to new fluid without taking a chance of airpockets or lines not filling up completely. If you drain it dry you will risk these problems, they recommend not draining it ever unless you do a partial by dropping the pan and allowing it to drip for a while, I waited 20 minutes but it still had drops every so often. I'm do for another change right now at 130k. That's why I came hear, to hear what fluids others have used. My buddy rebuilt a tranny and used synthetic even though I warned him not too since the manual was very strongly recommending to not do it. His tranny was junk in 1 year. It was a Ford F150 truck that had the Natural Gas conversation that used either fuel. I figured this might help others that are having automatic trans problems. Total cost for a diy change is about $60. Can't remember if I used Mercon 5 or 6. That's what I'm checking next.my guess is 5.

i have an 03' v6 mustang and it will shift hard for a while so i took it to aa mechanic and it wouldn't do it for him would it be the pump or electrical issues?

I've had this issue on my 2014 3.7 Ford Mustang Auto. It progressively got worse over 3 years and could never figure it out. Finally gave up and took it to Ford. After a week of troubleshooting, they found the issue was with the transmission valve body. They found no metal shavings in the transmission and the tcm seemed to operate normally. The occasional slipping was fine at first but after letting the car sit a week, the slipping would occur once a day, and then the car would immediately go into limp mode.

How did you correct the problem?

Askhay how did you fix the problem? I have a 2001 mustang I just bought. It’s automatic It pulls in all gears but it won’t shift out when driving. Does anyone have any ideals on what could be wrong with it? I knew it had shifting problems when I bought it. I got the car for 600$ and the body and motor is good. I figured for that price if I would have to replace the tranny it’d still be worth it.

Randy, I don't get your comment so you state the car running by itself won't change gears? or, it only does shift manually? For 600$ on a low mileage V6 new edge, it's a good price, I know those are rock reliable, minus the transmission sometimes, I love my mustangs but i always look out for stick shift ones over autos anyday, even I own a foxbody with auto AOD, I wish I could afford to convert it to stick. Take it to a reliable mechanic since 99% of them are thieves and even knowing your car could have a minor issue, they would tell you you need a major transmission overhaul.

I got an 05 automatic mustang car want shift I'n any gear pulled it out put a good one it that I no for a fact was good it's doing the same thang what's my problem anybody ever rum into this problem

GuruKM8H8 that happened to me years ago with an old Pontiac Sunfire. Blew out the trans, and a mechanic put in a good used one. Worked for a couple of days and then that one blew out too. Turned out it wasn’t the trans, but the computer that controls the transmission. Replaced that, put another good used trans in it and it ran until I junked it.

I’m here because I have a 2003 Mustang V6 that’s shuddering hard shifting into second (auto trans). Checked the fluid hoping it was that-nope, it’s full. I think I’ll take it in and have it flushed. I also have a 2008 Focus that’s shifting hard occasionally from reverse to drive and sometimes on downshift. Fluid is full on that one too

Why do your transmission shift don't go and to third gear

Transmission slip is a common issue but not a common, you should focus on it I write on this topic a research base article you should check my work. https://universalmotorcarslv.com/how-to-tell-if-transmission-is-slipping/

My brother n law has an 06 v6 mustang with 108000 MLS, trans started shifting hard when battery was weak and needed jumped, I checked battery because it was a serviceable one and it was near empty. Once I filled battery and charged it, trans started shifting smoothly and runing better over all. All his problems were just a weak battery. Easiest transmission fix ever.

I have a 2002 Ford Mustang GT I took the manual transmission out and put a automatic in it and it went to limp mode how do I get it out of limp mode

I have a 98 Ford mustang 5 speed v6. The car runs fine but won't go into gear. It just sits and revs up. What could be wrong with it?

i have a 2003 mach 1 and it needed a clutch so i took it and got a clutch for it now it recently started to be hard to shift i have to pull my foot all the way up for it to shift into gear, now it won’t go into gear at all it shifts into gear but not actually in gear but it don’t go in and my car won’t move any one know the reason?