85 4Runners use a W56-A transmission. You can install either the W56-A or W56-B. These can be found in 1985-1988 EFI Pickup and 4Runner. This is an easy bolt in deal. Other transmissions including the G series and W56-C and W56-D can be used but these will require some changes in the transmission shifter position.
Marlin Crawler has rebuilt W56 transmissions for your application for $799
I've got an 81 pickup and it was on it's 3rd "generic" rebuild transmission.. Massive bearing noise and eventually the main bearing failed and started to pop out of gear.
I got rebuilt HD version from Marlin.. It wasn't cheap, but I bet it will be lasting longer than the other 3 that were in my truck.. The 85 tranny is a better tranny - still - see Marlin, I think it's money well spent.
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