75w90 verses 75w140 questions

[Orrin]

I am sure this has beat to death, but I have not had my 2005 Escalde AWD very long. I am going to change the differential gear lube and am thinking of going to 75w140. I know it has to be synthetic.

I have done a search but did not come to a conclusion. Both should do a good job. I am hoping the 140 will make the gears a little quieter (they are not very noisey now), but am concerned about foaming and heat build up with heavy lube. Any reason not to go with the heavier lube?

Thanks for the input in advance.

 

[El Capitan]

Im running 75 140 in my rwd tahoe no problems

 

[Max]

75/90 is fine with any good synthetic. You can run 85/140 if you tow a lot but I run royal purple 75/90 religiously.

 

[Buzzcut]

I am sure this has beat to death, but I have not had my 2005 Escalde AWD very long. I am going to change the differential gear lube and am thinking of going to 75w140. I know it has to be synthetic.

I have done a search but did not come to a conclusion. Both should do a good job. I am hoping the 140 will make the gears a little quieter (they are not very noisey now), but am concerned about foaming and heat build up with heavy lube. Any reason not to go with the heavier lube?

Thanks for the input in advance.

What does the owners manual say as far as viscosity?

 

[Freedom Motorsports]

You can run either, the 140 is more for those who haul with their vehicles often. As for it quieting the gears, there MAY be a slight difference, but I doubt it will be enough to notice.