90wt gear oil

[Ncrover725]

Since day one I have used Lucas 90wt for all my requirements. The Lucas cost about twice the average generic brand ( napa, advanced auto, ect..) oil. Is there a difference in these oils or am I just wasting a bit of money? I'm looking to drain and fill everything this payday and spending half as much could be a good thing.

[TeriAnn]

I have no idea why anyone would use Lucas oils. I have no idea if it attacks bronze or not, so can not comment on your current choice of oil.

I have been using Sta Lube GL-4 Hypoid Gear Oil for over 30 years with no issues. GL-4 is an old standard but it is a bronze friendly standard.

Meanwhile, I have moved to a climate where it actually gets cold in the winter and have been thinking of going to RedLine synthetic gear oils for reservoirs that do not leak because they work better on cold winter mornings.

I'm thinking of switching to Redline 75W90 GL-4 gear oil for the gearbox, staying with the less expensive Sta Lube GL-4 for the leaky transfercase and going to RedLine 75W140 GL-5 Gear Oil for the diffs which don't leak.

[jonnyc]

Anything that leaks gets the cheap stuff. Come to think of it, I pretty much only use the cheap stuff.

[Rat Patrol]

I'd say Teri Ann has the right idea, especially in colder climates. I still run the standard stuff here in WY but seriously considering synthetic as its not much above +30 & more like the teens with wind-chill....takes a few miles to warm up the gears.

[scatterling]

Napa sells Pennzoil Gearplus 80W90 GL4
- Stock No. 4804.
It's what I use.

[jac04]

I also use the CRC Sta-Lube 85W90 GL-4 gear oil. I buy it at NAPA.

[antichrist]

Rumor has it that the newer additives used in the GL5's don't attack yellow metal the way the older ones did. I've no idea how true that is.
When I lived in Vermont I ran Drydene 85/140 year round and yeah, it was definitely thick in the winter. On really cold nights I'd put it in low range when I got home in the evening.

[Kiloengineer]

I am in the process of changing everything over to Amsoil Synthetic. Are there any issues with using synthetic in Series Gearboxes? Except for the cost?

[scatterling]

they will leak ( a lot more than usual)

[jac04]

Rumor has it that the newer additives used in the GL5's don't attack yellow metal the way the older ones did.
Many oil companies have changed over to using non-active sulfur to address nonferrous metal attack issues. However, I've never seen a bottle of GL-5 designate active or non-active sulfur in the EP additive package. Some GL-5 oils state that they are formulated to be noncorrosive to bronze and other yellow metals. IMO, it's better to be on the safe side and use the GL-4 oil that is specifed for our vehicles.

[TedW]

I am in the process of changing everything over to Amsoil Synthetic. Are there any issues with using synthetic in Series Gearboxes? Except for the cost?

I've used Amsoil (or Mobil 1) 90 weight in everything for the past 20 years. No problems, but lots of benefits - it gets cold up here.

Also, FWIW, I have not found synthetic to leak out much more than regular dino does. In my view the benefits far outweigh the drawbacks.

[73series88]

i put cheap stuff in. it works for me
aaron

[TedW]

I've told this story before, but IMO it's appropriate for this discussion:

Back in the 90's we had a nasty cold snap up here: it was -30F in the mornings.

Perfect conditions for a gear lube test!

I left two bottles of gear lube out on the back porch overnight: one was Amsoil synthetic; the other one was conventional dino 90wt.

The next morning (-30F) the dino lube squeezed out of the bottle like rubber cement (or like a big nasty booger - I'm trying to be descriptive here).

The Amsoil, OTOH, didn't seem any thicker than it was in my basement the night before.

This really sold me on the value of synthetic gear lube, and the performance and drivability of my truck improved significantly after I made the switch.

Just my $0.02.

[Ncrover725]

After reading the responses I wound up acquiring a five gallon container of mil spec 90 wt from work today and changed my fluids in the tranny, overdrive, and transfer. After I changed them I drove 40 miles back home. I will say there was a noticeable increase in drive train noise. Maybe it was just coincidence or the Lucas heavy duty 90wt keeps it a bit quieter.

[SafeAirOne]

I think the Lucas is advertised as being able to quiet down gearboxes.