Dave D Dee

Cheers I am new to jeep ownership and need advice. My son and I have a 1996 5.2 l Grand Cherokee Laredo,,360,000KM I rebuilt the 5.2 and runs great.. but the transmission has lost 1 first gear. Replaced 2 solenoids as per the u tube vid for 1 st gear issues but still not working,,, it will go into 1 st if we go from park to 1 st than manually upshift with shifter,,, but I give up. I have been told by some that a 42 RE from a 98 cherokee 4 l will work,, is this true? ..note I have a 231 and a 96 replacement original for the transfer case( 242?) sitting on the shelf,, so will a 42RE and 44 interchange or fit on the 96? ty in advance Cheers Dave