Thanks for the detailed reply. Your info is always the best. I am pretty sure that I would trust you over Toyota now!I'll add. IIRC your rig has been flushed before. I'd just do a full flush than. Unless fluid smells burnt. But even then I get to a full flush after just a few dain & fills. You go off road so much with that beast. If trans going to fail, find out now. But I'm 90% sure, a full flush is not going to reveal a weakness.
BTW are you monitoring your ECT (engine coolant temps)? If so what are you seeing?
The color of my trans fluid still looks really good. This is pretty impressive given that my truck tips the scale somewhere north of 7000 lbs and most all of my driving is in the mountains going up and down in elevation. I just want to make sure to keep up with the maintenance so that I can make it to 500k. I 100% agree with what you are saying about a normal flush not being an issue. We have also discussed avoiding power flushes which like the plague.
I also agree that if a part is close to failure, I would prefer to have it go where it is hopefully easy to fix. Or in the event of the transmission, close to your shop!
Coolant I have seen a range in temps of between 173 to as high as 198. The average is right around high 170s to low 180s when moving. The 198 was when I was moving slowly on trails in Moab and it was full sun and about 95 degrees. Even that was only for a moment before it came back down to the mid 180s.
Trans temps seem to be between 135 to 165 in normal highway usage. When going over mountain passes or climbing off road I need to lock it in a lower gear to keep trans temps in check. Without locking the gear, trans got up to about 215 when going over Monarch Pass. That is the highest I have ever seen the temp go. I usually maintain higher trans temps off road because of all of the climbing. I now make sure that trans temps never go above 190. If they start getting into the upper 180s, I will usually switch over to low range. This will cause the temps to drop quickly back into the 150s usually.
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