4RUNR_FAN

I just got done with some major fluid changes after approx 40K miles yesterday..
total mileage on the truck is 131K; got the truck in 2005 with 71K miles on it
and somewhere around 80K I had done all the fluid changes....

Front Diff Fluid was nice and clear...I could have left it as is...but I swapped it
out anyway....Used Mobil1 75W-90 (I think I used Penzoil on the previous
change out after I got the truck)

Rear Diff Fluid was ditto... (Used Valvoline 80W-90 dino gear oil); could not get
Mobil1 80W-90


Transfer Case was a little colored; somewhat brownish. Used Mobil1 75W-90


The truck is a road queen mostly; with very light off-roading a couple of times
a year so I was curious about the transfer case degrading faster than the diffs....
I do use 4WD a lot when there is snow/slush and or heavy rains around here
in the Boston area. Sometimes my 4wd engagement vs. disengagement light
blinks for a while and I will have to see whether it improves that after this
changeout.


Any thoughts on why transfer case fluid was more "thrashed" than the diff fluid after
40K miles?

Matt

mkgarrison5

could be left over crud from the previous changes or maybe its more harsh on the oil than the diffies.. there is a faint possibility you are getting dirt in there but it would be hard to pinpoint that even if its a possibility. you can use 75w90 in the rear diff.. preferabley 75w/110 would be better in a synthetic

4RUNR_FAN

Thanks for the input...I think I will leave the diff fluids alone for much longer next time around (perhaps for the rest of the life the vehicle has with me) and change the transfer case every year just to be on the safe side.

Now to tackle the external tranny fluid cooler one of these days....but without a garage these days so that will have to wait a while....