Torque converter shutter.

Yep no lockup in reverse! I going out on a limb here I kind of remember limited slip diff before they came up with the electronic stuff. They had clutch packs and required LSD oil I'm kind of wondering it that might be the shutter seems it's only doing it on a turn If it's dry or maybe the wrong oil that could be the issue. Don't quite me but I think they did.

 

Do yourself a favor and check your carrier bearing before you install that lubeguard stuff. A properly functioning transmission does not need any additive crap to operate properly.

 

Tacoma Shudder solved! My 2010 had the "Tacoma Shudder" for several years. Local dealer service manager was awesome: replaced transmission 3 or 4 times, transfer twice, flushed and refilled, tried additives, replaced entire drive train, radiator, etc. All cost to me was around $5,000. Usually experienced initial respite from shudder, only to return within 30 days or so.
One day about 18 months ago, the proper series of warning lights indicated a bad oil control valve (about $450 repair). After replacement, shudder was gone and never came back!