How to change 1rst gear ratio 5R55E

[JOEZ33]

I've done searches and didn't see anything so I'm puttin the question out there. I have a problem with my 5R55E and am about to pull it apart. While it's apart I'd like to change the gear ratio of 1rst gear. Stock is 2.47:1, I'd like something much nicer like 3:1. Maybe there are interchangeable parts from the 5R55S model? I know mustangs have a slightly better 1rst gear in the 55E.

While I'm at it is there a better overdrive ratio? Has this been done and where can I get the parts?

PS: the problem right now is that 1rst gear just started grinding/whining loudly. This started this morning when I put in reverse and got a loud BANG followed by grinding in reverse. Now it seems reverse is ok again but 1rst is noisy and probably about to blow up. It's got about 25K miles since rebuilt last. Clutches are all good, nothing slips, converter is good and quiet. I just want to fix and reinstall, very low budget.

 

[2000StreetRod]

Changing 1st impacts 2nd

The 5R55E has the same number of actual gears as the 4R55E. The second gear ratio is achieved by engaging 1st and overdrive. If you change 1st gear then second will be impacted.

 

[JOEZ33]

I know, first gear (2.47) x overdrive (.75) = 1.86 but I want 3.2 first gear and 2.2 second

 

[JOEZ33]

From talking to one retired transmission builder, this idea is supposedly possible. However the computer will disagree with the incorrect internal speeds of the tranny so computer mods are also in order.

Also it seems that the internal parts are interchangeable for the most part between the 5R55 series. If anyone has some torn down trannies let me know if your selling any parts. Mainly I need parts out of a 5R55W since my main concern is first gear, not overdrive. 55W has the same overdrive as I have now. It would be nice to change OD also, but for right now I'm just seein if its gonna actually work.

 

[MadScience]

Well with a manual it shouldnt effect the pcm that much. as it would with an auto. I was strongly considering a 3 gear splitter in my truck. making center straight through slot 1 ultra low and 3 little higher. so I could have amazing gas milage on long trip and have good wheeling power too. there is a whole lotta room for a splitter on an x. Might be hard to locate all the adapers though. 2wd or 4wd??

 

[JOEZ33]

I got info from Level 10 transmissions, they told me it's $498 for gear ratio parts and another $398 for software reprogramming. Sounds crazy expensive, I know I can do better than that. If the internals I'm installing are completely STOCK parts from another USED 55S or 55W than it can't possibly cost that much for some clutch packs and planetary gears. Of course they also quoted me $498 for the "master rebuild" kit. Most other "master" kits (of much lower quality) are only around $140- Level 10 is of course very $$$$.