Dealer Recommends 75w140 Gear Oil

So planning on doing rear, front differential and Transfer Case fluid change and I've used and read on hear that 75w90 is the go to for this. However stopping in at the local Toyota dealership to pick up the crush washers I see bottles of 75w140 gear oil so I ask the parts guys what they use for Tacomas and he says 75w140. So now interest is sparked and I go to the service department and confirm that they do indeed put 75w140 in the differentials. Know I'm not sure what to go with 75w90, 75w140 or in between 75w110? Anyone have advice? I live in an area where temps get to -10 to 100, and I do tow a 20ft pontoon boat 2hrs round trip every other weekend in summer.

 

Been running 85-140 for about 2 years. Depends on a couple of different factors, like the climate you live in for instance.

 

75/140 full synthetic.

 

Lucas 85W140 front and back for me as recommended by ECGS.

 

Yes .. Also non-synthetic .. But this would be for aftermarket gears .. If I had stock gears it would be full synthetic for sure.

 

Lucas 75w90 synthetic in all 3 a few weeks back and its running nice and smooth.

 

Thank you for the information gentlemen! Planning to put 75W140 in front and rear diff and 75W90 in T-Case. Since I do tow a 20ft pontoon boat and mostly travel highway speeds, along with pulling a 20ft pontoon boat from time to time. I want to make sure I use a heavy enough oil that will keep film strength when it gets hot. Thinner oils will loose strength when they get too hot and won't keep a good film layer of oil on the gears.

 

Lucas 85w140 in the front and 75w90 in the rear.

 

Yea dealer says 75w140 rear diff and 75w90 errrthing else. I asked for an explanation on change and they gave me a lukewarm meh as an answer. Manual does say 75w85 gl-5 rear diff but no one has a reason why. 140 is thicker, so in places that are colder this may not be recommended

 

No issues with 85W140 down to almost -60°.

 

Yea they are so similar, only thickness is the real difference. Thicker may take longer to warm up in cold climates, but honestly as long as you change it at regular intervals everyone will be fine no matter the weight they use. Maintenance is king ding-a-ling no matter the situation.