5R55s Replacement Advice

[Grubb]

The time has come, my transmission has decided to start acting odd. No CEL's at all but it has the drive to reverse issue where it takes its time finding the gear and sometimes I will be at a red light, in drive with foot on brake and the transmission will sometimes try to engage.... like the convertor is locking up until the car almost dies, like letting out the clutch on a manual without releasing the brake, don't know if its the solenoid, convertor... not sure I have the time or patience to find out. Has anyone replaced a 5r55s with a rebuilt unit online? or a performance one? can't afford a TCI right now so thats out of the question, I would like to get a transmission and torque convertor (possibly higher stall) all for around 2k, any opinions? Thanks Josh

 

[07 Boss]

A "good" converter is going to cost you a grand by itself. Are you planning on swappng it out yourself? I'm on my third. The stock one never failed but I swapped it to a Level 10 unit when I installed my blower. Lost my PI converter and had that rebuilt. Then lost the Level 10 "bulletproof" tranny and had a local shop rebuild it. It was like $3300 for the Level 10 unit. It was about $2800 for the rebuild but was guaranteed for 3 years of racing abuse. or 50K miles. Either way, unless you pull and rebuild yourself it's gonna cost you more than $2K for any kind of performance unit. Don't know how much a used stock one will cost. Seen some re-manufactured ones for for around $1300. The stock 5R55S is a pretty weak unit. If you run any kind of power or drive the car hard I would not recommend going with a stock unit. At minimum, input shaft, red or blue bands, solenoid pack, servo bore service/modification is what I would recommend.

 

[tjm73]

4R70W and be done with that POS 5R55S. A 4R70W is good to 500 hp as delivered from Ford. Probably cost just above the $2K ball park. US Shift contoller/ convertor/ tune.

Ford has 2 good automatic overdrive transmissions. 4R70W and 6R80. The 10 speed is too new to add it to the list. It has to prove it's good still.

You could also put a 6R80 in it, but I doubt you could do it for your price target.

 

[Grubb]

I will be doing the work with a friend, I've been looking at the level 10 stuff but it's looking like a lot of money without much guarantee. I'm leaning towards swapping to a 4r70 at this point.


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[Speedboosted]

Do a 4r70. I have a 5r55 in the Paxton car and while it's nice to just put it in Dumb and cruise around, I'm always afraid it's going to let go.

If I keep the car through the winter, it's getting a big boy head unit and a built 4r70 lol

 

[RocketcarX]

Get a used 4R70W, they are everywhere and usually 5-700 bucks. It will hold up fine and when it does go out you can then really upgrade it. In the mean time I would be more concerned with getting everything fitted using high quality parts, the used trans will open the budget for that to happen. A 90 day to 6 month warranty is not uncommon with this trans used.
Look on eBay as well for them.

 

[TexasBlownV8]

I'd highly recommend an upgraded/hardened stub-shaft in the 4r70. Mine shredded with only around 500 hp.

 

[Grubb]

I'm searching out a good deal on a 4r70w now, what would be a good convertor stall for the 4r70/4:10's, car is just driven for fun, no track use.

 

[RocketcarX]

I'm searching out a good deal on a 4r70w now, what would be a good convertor stall for the 4r70/4:10's, car is just driven for fun, no track use.

2600ish or a little more. Make sure it's a street converter so it's "tight" under the stall.

 

[Wild White Pony]

Been where your at now, my stock trans with a hardened input shaft and a catch can lasted 10 yrs, spent 4K and purchased a Level 10 pile of shit since it was late in that year and I still wanted to get some runs in, well it lasted less than 6 months. Did the 4R70W swap, save money swap. When your done it can look and drive just like stock if you opt for a automatic valve body and a trans controller like the Quick 4.

Like mentioned in 3rd post, you may want to figure a cost comparison between lightly built 4R70W and the 6R80 Swap, the 6R80 stock can handle a lot of power, the controller may be a bit more in cost.

Here is where I put my trans controller, I have a switch for trans controller race or street tune and a burn out mode switch. The O.D. I just open the console and hit the controller knob to deactivate, the Lockup I inhibit in the race table since it's a single disk lockup converter. If you get a nice triple disk like a circle D you may lock up the converter and get more top end.

 

[tjm73]

....what would be a good convertor stall for the 4r70/4:10's, car is just driven for fun, no track use.

What RPM does your torque peak at? Roughly same as stock?

I could write a long winded explanation on this, but I am 400 miles from home on vacation in NJ and don't feel like it. So I'll keep it real short. Run a Ford factory converter from a 2003-2004 Mustang GT/MACH 1/Mercury Marauder (all the same convertor). It should stall around 3000-3200 rpm behind the 3V engine. It is said that you should have stall be 700-800 rpm below peak torque. 2006 GT's peak around 4500. It sounds a little high, but with lock up it's not. It also gets you into the game at a price that is A LOT lower than a fancy aftermarket convertor. Like $200-250 versus $800-1000. Aftermarket is better, but you pay for it and you can upgrade later. This fits the budget right now and brings performance and it's a total bolt in.

This would get you up and running on the cheap and allow you to assess the stall. You may find you like it or you may find you want less or more. And then you can buy a quality aftermarket unit stalled the way you want it and also get the benefits of a smaller diameter aftermarket unit.

Ford rates the 11 1/4" Marauder/'99-Up Mustang GT/MACH 1 converter at 155K (Ford does not rate "stall"). According to multiple sources of this info Ford only made one stall rating in there 11 1/4" converters. In 2003-2004 the Marauder/MACH 1 got the exact same converter which has one difference from the Mustang GT. The Marauder/MACH 1 converter is furnace brazed. (I have also read all converters were brazed starting in 2003 or so)

Ford K values are based on 294 ft-lbs of input torque.

Stall speed rating is defined by the following formula:
S = K * (Nm^0.5) where;

S = Stall Speed
K = The K factor
Nm = Torque in Newton-meters (Convert to Nm = 1.3558 * ft-lbs)

So, with a 155K factor the stock OEM convertor would stall at about 3200 rpm.
155K * (320 * 1.3558)^0.5 = 3228

And the 11 1/4" converter is good to 6500 rpm so balooning shouldn't be an issue for a driver.

So much for not being long winded.

 

[Grubb]

Perfect answer, thanks

What RPM does your torque peak at? Roughly same as stock?

I could write a long winded explanation on this, but I am 400 miles from home on vacation in NJ and don't feel like it. So I'll keep it real short. Run a Ford factory converter from a 2003-2004 Mustang GT/MACH 1/Mercury Marauder (all the same convertor). It should stall around 3000-3200 rpm behind the 3V engine. It is said that you should have stall be 700-800 rpm below peak torque. 2006 GT's peak around 4500. It sounds a little high, but with lock up it's not. It also gets you into the game at a price that is A LOT lower than a fancy aftermarket convertor. Like $200-250 versus $800-1000. Aftermarket is better, but you pay for it and you can upgrade later. This fits the budget right now and brings performance and it's a total bolt in.

This would get you up and running on the cheap and allow you to assess the stall. You may find you like it or you may find you want less or more. And then you can buy a quality aftermarket unit stalled the way you want it and also get the benefits of a smaller diameter aftermarket unit.

Ford rates the 11 1/4" Marauder/'99-Up Mustang GT/MACH 1 converter at 155K (Ford does not rate "stall"). According to multiple sources of this info Ford only made one stall rating in there 11 1/4" converters. In 2003-2004 the Marauder/MACH 1 got the exact same converter which has one difference from the Mustang GT. The Marauder/MACH 1 converter is furnace brazed. (I have also read all converters were brazed starting in 2003 or so)

Ford K values are based on 294 ft-lbs of input torque.

Stall speed rating is defined by the following formula:
S = K * (Nm^0.5) where;

S = Stall Speed
K = The K factor
Nm = Torque in Newton-meters (Convert to Nm = 1.3558 * ft-lbs)

So, with a 155K factor the stock OEM convertor would stall at about 3200 rpm.
155K * (320 * 1.3558)^0.5 = 3228

And the 11 1/4" converter is good to 6500 rpm so balooning shouldn't be an issue for a driver.

So much for not being long winded.

 

[tjm73]

I only know this because I have been researching 4R70W's for my 331 foxbody. The engine is powerful enough to have wounded the T5 and I have a 4R70W so I can get a transmission that is almost bullet proof in my drive line for less than a TKO600. Still on the fence.

The big benefit to the aftermarket convertor is 1.) you can get a recommendation from someone with experience based on talking to you about your car and it's use, and 2.) it'll be a small 9.5"ish size that will put more power through. Less mass to spin and a little less fluid in it too.

 

[tjm73]

Thought of this and was wondering if you had made any movement.

 

[Cardriver333]

Thought of this and was wondering if you had made any movement.

I'm looking at a 5r55 swap soon. Is the 4r70 easy enough? I'm looking for reliability with a stock v6.

 

[TexasBlownV8]

I'm looking at a 5r55 swap soon. Is the 4r70 easy enough? I'm looking for reliability with a stock v6.

For a stock V6, stick with the 5r55s. A 4R70 is meant for a v8 block/modular V8, and the bellhousing is different in the 4.0L you have. Not to mention all the other changes to make one work.
FWIW for those with a V8, a 6R80 is the more common and preferred upgrade now, espcially if you need to handle more power.