Proper weight of gear lube oil in differential

[pattypape]

Yep same here,

Twice a year seems a bit much, I think this was the first change
for our 88. This could start the viscosity debate again.


Bill FC Michigan no leaky read end here


--- In WanderlodgeForum@yahoogroups.com, "mrdonut12"
<mrdonut12@y...> wrote:
> I've got a slight dilemma regarding which gear lube oil
> to run in my differential.
> I consulted an industry expert who owns a heavy duty
> fleet maintenance shop and works on trucks all day. He
> said that GL-5 80W90 gear lube oil would be fine in my
> Rockwell 5.29 gear ratio differential.
> That's what I put in.
> Digging through my Blue Box, I accidently ran across
> some papers that stated Rockwell advised using 85W140 oil.
> Since my Bird is so old, I wonder if lubrication
> technology has made that recommendation obsolete, or if
> I should switch to that weight.
> The lubricants made in 1981 are a far cry from what's
> available today.
> The book also stated that, if you drive less than
> 60,000 miles per year, the gear lube should be replaced twice
> a year, Spring and Fall.
> That's what I'll do. Any experience on gear lube weights?
>
> George Witt
> 81 FC 35
> Lincoln, Nebraska (60 miles down the road from the
> College World Series--Huskers play Friday night)