2007 F150 5.4 burnt reverse band

[CP]

Make

Ford

Model

F150

Year

2007

Miles

186000

Engine

5.4

Rebuilding this 4R75 for a customer that had no reverse. A lot of filings but really all I found wrong to not make it reverse,was a burnt reverse band. Any ideas why this would happen? Checking things carefully going back together and doing a few updates to fix the weak areas, so had another question? The forward and reverse clutches could use thicker snap rings by 1 step. Anyone have the Ford part numbers for both snap rings in the .088-.092 range? Or where else can I find them? Also is the clearance supposed to be .040-.059 for the reverse clutch with a 3 friction set up? My book says that clearance for a 4 plate assembly

Thanks

 

[bp042665]

as for different snap ring you can get them through any transmission shop or have them order them through there parts supplier i use what ever it take transmission parts or transtar the clutch clerance should be the same 3 or 4 clutches drum as for what burned up the band check the servo for hardness if hard replace it