At 129k on the Jeep, when replacing the torque converter with a Suncoast TC, my front pump was replaced with a new one and a Transgo kit was installed at the strong recommendation of my very good friend who owns and runs his own transmission repair company.
He stated that the Transgo kit firms up the shifts and helps line pressure to make everything function better...
He had already put one (transgo kit) in my Dodge Cummins several years ago (2000) when installing a Suncoast in it and I can personally attest to the fact that it made the shifts firmer on the Dodge. As to the Jeep, it also seemed to make shifts and lockup a little more firm with less slip...
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Supporting Vendor and Moderator of LOST05 Jeep Liberty CRD Limited
Ironman Springs/Bilstein/Shocks
Yeti StgIV Hot Tune
Week's BatteryTray
No FCV/EGR
Samcos/ProVent
SunCoast/Transgo
Carter Intank-pmp
2mic.Sec.Fuel Filter
Flowmaster/NO CAT
V6Airbox/noVH
GM11 Bld.fan/HDClutch
IronrockArms/wwdieselMount98 Dodge Cummins 24 Valve