It doesn't need a whole overhaul unless you have shifting issues. These transmissions are pretty bulletproof other than leaks and the reverse bands.

What I discovered today though -- if you replace the b3 bands, change the fluid + filter after 5k miles because your pan will be dirty filthy with the bedding in on the new bands.
First time I've pulled mine today and its been ~15k since I did it.

Find a shop that knows these transmissions and you won't have those questions. If they refuse warranty, find someone else because they probably have no idea.

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2016 Monsoon Gray Audi Allroad - 21k
2008 Black Mercedes E350 4Matic Sport - 131k
2014 Jeep Wranger Unlimited Sahara - 62k
2003 Gray Mercedes ML350 - 122k