My 2005 Ford Econoline E350 van with 5.4 L gas motor with the 4R100 transmission is slipping in overdrive! Trans was previously rebuilt at 90,000 miles and now at 149,000 miles it's coming up with the same problem again!
Prior to my 2005 I owned a 2003 350 van with the same driveline with the exception for the 355 gearing can rack up over 300,000 miles with no major problems! My 05 E3 50 is equipped with the 373 rear gears and I'm curious to know if there's any alternative transmissions or ways that I can modify existing transmission so I don't have to go through this process again?

One, can I Bolt in an Allison five speed transmission?

Two, will a 5R110w Trans supplant the 4R100 and is it compatible
With my 5.4 and computer?

Three, can I modify my existing 4R100 for more durability?


Thanks

Gregory

05 Ford E-350 Van
63-1/2 R-Code 427 Galaxie 4spd Blk/red
92 SHO 5- spd Blk/Blk