Transmission performance.

[stugots]

Yeah I know another transmission thread.. I think i've read them all and nothing really answers my questions.

I have a 2003 v8 70k btw, first off I think this transmission is alright no real complaints on shifting Except for the 2-3 upshift. I know its a tough shift for this transmission but 50% of the time is just straight sloppy.

I know of the solenoid problems, but I have no delay shifting into reverse/drive. 1-2 is crisp most of the time, 3-4 is solid, 4-5 alright. Its just that 2-3, it can be explained almost like a shudder. Kinda like a manual trans sometimes. Its not harsh and almost has an elastic feeling. It feels like hitting a small break in the road sometimes. It used to do it 80% of the time, but since unplugging the battery, its pretty much a hit or miss. (mostly under moderate to full throttle) I don't think anyone else can really notice it unless told, I don't want you guys to think its this horrendous shift.

-Am I just expecting too much from this shift?

-How does your guy's 2-3 shift feel?

-Should I just replace the solenoid or the solenoid and valve body?

 

[Shredicus]

You may want to look into getting a tuner/tune or unplugging your battery cable overnight to relearn your driving habits but drive it more aggressively. Apparently the aggressive learning helps smooth shifts out sometimes from what I've read. If you think it's a mechanical issue though generally just the solenoid is replace but there is also a valve spring that is known to fail occasionally that you may want to replace while you've got everything apart.

 

[stugots]

Thanks i'll try the relearn again. I know you have a 03, have you had any transmission problems? It seems like the 03's have slightly different problems than the 04s.

 

[Shredicus]

Thanks i'll try the relearn again. I know you have a 03, have you had any transmission problems? It seems like the 03's have slightly different problems than the 04s.

I definitely get what you mean about the rough shift between 2-3 but I havent really noticed it since I got my transmission fluid changed. I dont know if it's just confirmation bias or it actually helped but a fluid change is always a good option before doing anything more drastic. It's weird though becuase mine would shift flawlessly under WOT but was a little sloppy when it came to more restrained driving, although I think that's a pretty common "feature" of these trannies.

 

[Kumba]

Has been discussed in detail before, but here's my take from my '06:

First off, a synchronous shift means that the transmission has to synchronize two individual actions inside the transmission to change from one gear to another. A non-synchronous shift means that only one action is required to change a gear.

1) The 2-3 shift is definitely a synchronous shift
2) The 1-2 shift is definitely a non-synchronous shift

So there are two individual actions required for the transmission to successfully shift from second to third gear. During the shift transition there is potential for the engine to freewheel at near max (or more likely max) throttle causing a harsh engagement in the transmission. In order to prevent this I think the PCM/ECU throttles the engine back slightly during the shift which is where you get the weird/sloppy feel. On mine it quite literally feels like the traction control kicked in for a split second during the shift.

By contrast, the 5r55n, which came in the Gen1, has an intermediate sprag and clutch that the 5r55s does not. This allows it to maintain fully non-synchronous shifts for all gear changes. The down side being a slightly heavier, little more complex, and costlier transmission for Ford. I'm guessing that the bean counters ultimately drove the decision to go with the 5r55s. A transmission that weight 20-pounds more and has one extra solenoid and sprag/clutch seems pretty irrelevant in the bigger scope. A transmission that was $100 more per unit to produce (just grabbing a random number out of thin air) was probably what the decision was based on. Have to remember, Ford used this style transmission in a ton of vehicles during mid 2000's.

I think the 5r55n is the better transmission once all the factory issues were worked out. From the threads here it seems like most of those issues revolved around Ford using bad transmission fluid that ate the solenoid packs up. I think they got that figured out in '03 if i'm not mistaken.

My 2-3 shift is somewhat harsh on the downshift, and harsh under throttle (3/4 pedal or more). With normal dont-act-like-you-stole-it driving it is fairly smooth. It's harsher with SST then D4/5. There is also the somewhat goofy gear hunt that it does at times. For instance, if i'm rolling along at 55 then coast down to around 20 for a light that just turns green and get back on the gas it will still be in 4th or 5th before bogging the engine and slamming you (half the time hard) into 2nd or 3rd.

Overall they are just minor annoyances. I consider them more nature of the beast then anything seriously wrong. If it started to slip, had late engagements, or was just harsh all the time then I'd be worried.

 

[stugots]

Thanks that is by far the best explanation i've read. I knew it was a different shift but that made me understand a little better. The part about how it felt like traction control kicking in kind of explains my feeling.

I'll probably do the re-learn again. It definitely helped the first time.

 

[oddball]

IIRC, on the 5r55S, 2nd and 3rd require a band to apply - different bands, as 2nd is really overdrive band + first, and 3rd is just the 3rd gear band. So the tranny has to release the overdrive band, wait for the drum to start moving, then apply the 3rd band. The improvements in sensors and ECU logic was supposed to make this workable. Stock calibrations didn't necessarily help the situation.

The best solution outside of regular maintenance is to get a custom tune that increases the line pressure in the tranny and shortens the shift.