Wally39

My car runs very rough and there is a vibration, hesitation, and my shift firmness is gone. I took it to a well known transmission shop and he could tell it was slipping especially into 3rd gear. The tranny fluid smelled a little funny too. He is going to find out if they make a performance kit for our automatics to beef it up after he fixes it. This will be his first time with a new Mustang tranny, because normally people take they're new cars to the dealership for warranty work. My dealer already told me it wouldn't be under warranty. Anyway, my question is do they make a performance kit for our automatics?
By the way, while I had my car custom dyno tuned yesterday, the guy didn't like the way my transmission was acting. It made the dyno graph look messed up.

MexGT

Check if the driveshaft is not messing up everything? don't know any other option i'm not an expert in this [&:]

cheftjpeck

r u running stock converter??

cheftjpeck

I am not sure if you are aware....but 3rd is the weakest gear on these cars....that is where the issue will start...with a supercharger you should really consider investing in a new good torque converter....will save your tranny...during my dyno tune my TC was slipping....sorry to hear about your plight....good luck...TJ

Wally39

Yes, it's the stock converter. Everything in my drivetrain is stock.

Mikes_BLK_GT

Becareful with 4th to as I understand it that is part of what makes the 5r55s a weaker tranny than the c-4 and 4r70w. The other reason is its just a smaller tranny. I have seen alot of posts on the torque converter and still dont fully understand them, and how they can affect driveability. I know that puting a higher stall will cause more "slippage" at lower rpm's but what this means to every day driving Im not real sure. It's also myunderstanding that the higher stall torque converter will shift better going into 3rd and into 4th at a higher rpm so I'm guessing it'll shift better going from 1st to 2nd as well(?) since your at a higher rpm.

forensicsteve

Some might say that I have gone overboard but I am building up my car to handle extremehardlaunches with a transbrake and very high-stall TC...so I decided to just replace the whole stock tranny from a company that builds transmissions for race cars. However, I'm certainly no expert and it might be sufficient to just fortify the stock one. It depends I suppose on your eventual goals and usage.

As far as driveability with TC of 4000 rpm...I drive it on the street daily but my commutes are very veryshort distance (mostly less than 4 miles). There definitely is a trade-off between race car and street car. Depends on what your thresholdfor comfort and convenience is.

cfr865

My 3rd. gear went also, I have read on other forums this is beginning to be a problem with FI cars. Is there anyone making heavy duty parts for this trans. or do you have to go with a complete new trans. like Level 10, which is very costly. How does a new high stalltq. convertor save the 3rd. gear band ?

zkiller

These trannies are all blowing up on third gear. I know of at least twenty just from the forums. My tranny third gear went 3500 miles after the blower went on.
If you want to keep the stock tranny one option isLevel 10 transmission makes a performance kit or theywill rebuild your tranny to Stage II or Stage III specs. Their kit has all beefed up (Animal) bands and clutches, a super solenoid to improve TC lockup, a super pump and more is inluded.
They also make a nice PTS billett converter that eliminates that funky second flex plate attached to the stock converter and is true locking converter with a billett case.
They also make a deep pan and dipstick. They have a completely manual option too with selctronic shifter an a transbrake.
The best thing is youstill have5 speeds and a super low first gear ration.
I installed the whole nine yards and it is a vast improvement over the stock tranny and converter.
They have a lot of knowledge on these trannies. I would not have someone who never worked on a 5R55S build you a new one. That is not a good plan. Also Level 10 believes if you shift the 5R55S over 6200 RPM it causes cavitation in the pump, which leads to early failure. They strongly advise shift points 6000-6200 RPM.
I did not use their tune. I have a custom dyno tune and so we got the tuning information from them and put it in the tune when we dynoed the car.
I have a big old convertible and after installing this TC and tranny I am getting my front wheel off the ground on launch.
It shifts much better than the transmission did in stock form and has held up to much abuse so far.
Or you can do an AODE/4R70W conversion or a C4 conversion for less money.