Last weekend I took the Montero to a U-Pull to pick up a bunch of parts (Radiator, Fan Shroud, Equalizer Radio, Tail lights, Skid Plates, Inclinometer Gage Cluster). It was a pretty good day! The trip was 2.5hrs each way, mostly highway. The temps were in the low 90's and I cruised at ~70mph on the way there without issue. Got all of my parts pulled and then started the trip home. About 1hr in while cruising at ~75mph (spent a little too much time at yard
) I noticed that my A/T Temp light came on. I slowed down to the shoulder and let it idle to allow transmission fluid to cool off. I idled for ~20min and light didn't come off, so I drove at very low speeds (~20mph) on a side road and after a minute the light went off and stayed off for the rest of the drive home. As you can see in the attached picture my coolant temp was low. For the remainder of the trip I kept my speed under 65mph. My transmission fluid was between the MAX/MIN lines on the HOT section of the dipstick while I was cooling, had a light honey color to it and didn't smell burnt. I'm not sure what fluid the PO had in it when I bought it.
Following this incident, I'd like to change out the fluid to SPIII and install a new screen in the transmission pan. I have ~200k on my transmission and don't see any indications that it has been rebuilt in the past. What I'm trying to figure out is if I should do a drain & fill and then drive for a while to allow the fresh fluid to loosen any build-up to get caught in the pan screen. Then after I have driven for a while I would drop the pan and clean it all out. I would coincide this screen change with the installation of the OEM radiator I got at junkyard in place of the cheapo plastic tank unit currently there.
Does the plan above make sense for a starting point? I'm starting to read through the FSM, but I don't see much information regarding the A/T Temp light other than it identifies the transmission fluid is >122F.