New to me maintenance, mostly diff gear oil
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New to me maintenance, mostly diff gear oil
Picked up a new-to-me (CPO) ‘23 F-150 FX4 (35k mi.) w/ the heavier duty tow pkg last week. As I usually do when I buy a pre-owned vehicle I’ll be replacing all the fluids, including brake fluid and generally going over the truck bumper to bumper. I’ll also detail it inside and out (it’s nice being retired!).
Yesterday I changed the oil & filter (damn they put that filter on tight!) and also replaced the gear oil in both the front and rear diffs.
The motor oil did look like it was recently changed but I’m glad I changed it with my known quality oil. I used the standard Motorcraft oil filter and Liquid Moly Special Tech 5w30 oil, I’ll either stick with that or use Castrol Edge 5w30 (both are full synthetic).
The gear oil in the rear was very dirty but at least it looked like it was gear oil at some time in its life. However the front diff looked like extremely dirty swamp water, I’m shocked that stuff was ever gear oil in the first place, you could have fooled me! I’m sooo glad I changed both of them but especially the front. I’ll more than likely do the front again next time I change the engine oil, it looked that bad!
Next week or so I’ll replace the fluid in the xfer case and do a drain/refill of the ATF in the transmission.
Which brings me to my question, I see that I can bring up the transmission temp in the gauges on the dashboard but it doesn’t state an actual value of the temp. Does it take a special OBDii reader s/w pkg. to read the actual temp in the transmission? I have the temp range it needs to be to set the fill level but I need a reader to read it.
Yesterday I changed the oil & filter (damn they put that filter on tight!) and also replaced the gear oil in both the front and rear diffs.
The motor oil did look like it was recently changed but I’m glad I changed it with my known quality oil. I used the standard Motorcraft oil filter and Liquid Moly Special Tech 5w30 oil, I’ll either stick with that or use Castrol Edge 5w30 (both are full synthetic).
The gear oil in the rear was very dirty but at least it looked like it was gear oil at some time in its life. However the front diff looked like extremely dirty swamp water, I’m shocked that stuff was ever gear oil in the first place, you could have fooled me! I’m sooo glad I changed both of them but especially the front. I’ll more than likely do the front again next time I change the engine oil, it looked that bad!
Next week or so I’ll replace the fluid in the xfer case and do a drain/refill of the ATF in the transmission.
Which brings me to my question, I see that I can bring up the transmission temp in the gauges on the dashboard but it doesn’t state an actual value of the temp. Does it take a special OBDii reader s/w pkg. to read the actual temp in the transmission? I have the temp range it needs to be to set the fill level but I need a reader to read it.
Last edited by pcarguy; Apr 22, 2026 at 07:57 PM.
