Tranny oil cooler

I will be pulling a NB19.6 trailer with my 2021 TRD Pro. I’m concerned about the temp that the tranny will have. The local toyota service mgr tells me the latter models have fixed the transmission oil cooler issues and I will be ok. Don’t trust them. Any suggestions. Oh and he says an aftermarket cooler will void my warranty.

 

Google shows unladen weight of that trailer is about 4250lb, and assuming full liquid load and all of your trimmings for staying in it is pushing that max tow weight of the 4runner. You'll find any number of people haul weights up that high or a bit below regularly. Tranny should survive, but a cooler would probably be a good idea. Jegs and Hayden probably the most common names for aftermarket coolers you can add yourself. Just route it inline in the system after your radiator connection lines.

Maybe the biggest consideration is brakes. Getting that weight moving is not nearly as hard as stopping it all. Upgrading your stock brake system and adding a trailer brake controller would be an excellent idea - Curt, Tekonsha, RedArc. Take your pick

 

Thanks very much.