If you read the specs on the one for the Liberty, it is labeled as an UPGRADE, that contains case, and valve body parts. For them to be any good, they need to be metal parts, and not plastic. This says that it; Prevents Common Limp Causes (prove it), Upgrades early designs to later specs, Fixes Limp, Special ring/seal upgrades. The model years say 88 and up, and 42RLE well, to a certain point, because these Liberty are not the same transmissions, AGAIN, anymore.
The transmission in the liberty is said to be a redesign by Mercedes, and will not require this kit, or upgraded parts. It is not surprising they lied to you...
The best thing you can do for the transmission is KEEP IT COOL. If you can ad another cooler, do it. If you have a RAD that has the trans lines through it, add an AUX cooler. If you don't have the RAD with the trans lines through it, and don't mind the work? Change the rad out for one that has TRANS hookups, then use the existing cooler as an AUX cooler.
The A604 kits were introduced by TransGo as well, with new check bearings, and so on. Well, the TCM eventually adapted to the kit, and it was back to normal shifting. With ELECTRONICALLY CONTROLLED shifting, it's hard to alter the pressures and shift solenoid speeds; because the TCM can adjust.
The SOLENIODS are pulsed, that's why that sound ratchety, for smooth easy shifts. If it's hard and solid shifts you want, the pulse to the Soleniods must be changes to a solid voltage hit, which can be done with an adapter. It ended up blowing the clutch packs anyway, because of the simultaneous releasing and applying a clutch at the same time...
Leave the transmission alone, unless you want to COOL it, otherwise, nothing is really going to make it solid or more reliable than the redesign already has.
