I purchased a 2005 GX470 a while back with 165k miles. Currently it's sitting at 170k miles and the transmission has mostly felt fine except for cruise control erratically shifting on hills occasionally.
I know these transmissions come with "lifetime fluid" in the sealed units and I assume the fluid has never been changed since the previous owner did all maintenance at a dealership and I see no record of it being done.
Looking around, it seems like there's a belief that if the transmission fluid hasn't been changed for a long time (100k+ miles), then it should NOT be changed since the sludge in it actually helps with not slipping.
Another camp is that no fluid is lifetime and should be changed.
What should I do in this situation? Take the chance on the fluid change or keep driving around with original fluids and wait for the transmission to break?
I know these transmissions come with "lifetime fluid" in the sealed units and I assume the fluid has never been changed since the previous owner did all maintenance at a dealership and I see no record of it being done.
Looking around, it seems like there's a belief that if the transmission fluid hasn't been changed for a long time (100k+ miles), then it should NOT be changed since the sludge in it actually helps with not slipping.
Another camp is that no fluid is lifetime and should be changed.
What should I do in this situation? Take the chance on the fluid change or keep driving around with original fluids and wait for the transmission to break?