Gear Oil question

[wrighthm]

Hi everyone, I am trying to find out if the gear oil that is available locally would still be considered acceptable to use instead of the recommended GL-4 80 or 90w. The only stuff I can find at the stores here in Lexington is a GL-4 140. It does not say anything else on the bottle, I am curious if I could use this stuff since summer is just around the corner. I am doing an entire gear oil swap tomorrow in everything from the transfer case to the steering box. With this oil would the pressure be too high or would it put stress on the components since it is 140? Does the 140 on this refer to the weight making it GL-4 140w or is it something different since it has no "w". I am going to use CV joint grease in the steering box this time as well, are there any specifics that I need to know in order to correctly use CV grease instead of gear oil. I really have trouble because nothing is very specific and I know there are recommendations all over the forum but it makes me second guess everything when you see posts that say GL-5 is possibly corrosive to certain soft metals in the drive line, so when I do find a 90w synthetic gear oil I look on the back and it says "suitable for both GL-4 and GL-5 applications" which would lead me to believe it is no good for the Rover application. I really need some practical advice on oils that are available at the large chain auto parts stores that I can use in all the gearing components of my truck. Thanks in advance and I would not be opposed to using a synthetic either since I am draining and refilling instead of just topping up. Help Help I'm trying to schedule a long Rover drive with some of the local guys this weekend, my buddy Chris is a National Geographic explorer and the NatGeo photographer is in town and Chris wants to take some pro pictures of my truck with his 63 IIA 88 at a nature spot thats about 50 miles away. I need my truck well Lubed!

[jac04]

You want to use an oil with the correct viscosity. 'Excess" viscosity will not help you, and it will typically shorten bearing life.

NAPA sells CRC StaLube GL-4 85W90 gear oil. It is the correct viscosity. It is readily available and you won't lose sleep over the whole GL-4 vs. GL-5 issue. It's what I use in the trans & x-fer case of my SIII, and in the 4-speed on my 68 Camaro.

Now, the issue really isn't GL-4 vs. GL-5. Some people claim that the GL-5 attacks yellow metals, but most gear oil manufacturers now use non-active sulfur phosphorus EP (extreme pressure) additives which don't attack the yellow metals. Also, even if it is the 'old' type additive, yellow metal attack usually doesn't occur until the temperature gets to about 240F - hopefully above the temp that any of your internal gearbox components experience.

The problem with finding a gear oil for use in transmissions is finding one without Limited Slip (LS) additives. The LS additives are usually what gives you problems with your synchros and causes grinding upon shifting.

So, if you can find a GL-4 or GL-5 that doesn't state that it has LS additives, then you should still be OK using it in your transmission. I have yet to find any GL-5 locally that does not contain LS additives. I used to be able to find Exxon Superflo 80W80 GL-5 without LS additives, but I believe it is no longer available.

[wrighthm]

Jac you truly are a guru, I feel privileged to share a forum with you and proud to share a passion as well. We are all shade tree engineers and I have a lot to learn from everyone. Thanks for the response and the knowledge I gained that I couldn't get anywhere else. I bought the sta lube immediately after I checked the forum!

[jac04]

Glad I could help! Rover folk are good people, and we all learn from each other.
My curse is that I'm a mechanical engineer, and I get to work with gear drives for coal pulverizers. So my day job requires that I know a little about gear lubes, which kind of carried over into my hobby.

[TeriAnn]

I use CRC StaLube GL-4 85W90 gear oil in places that leak and redline synthetic in places that don't leak. The Redline synthetic makes a GL4 oil for gearboxes that is better at heat dissipation and stays thin in cold temperatures. Makes for grind free shifting first thing on winter mornings when the temp is well below freezing.

MTL 75W80 GL-4 gear oil for the gearbox and transfercase.

75W90 gear oil for diffs and swivels

Redline synthetic oils are not cheap but it is what you want when driving in the real colds full day trail driving and for long distance driving.

[TedW]

The amount of leakage in your rig can be a significant determining factor in the choice of lube. I switched over to Amsoil years ago, and have seen no noticeable increase in leakage. I did get a little more out of the TC cover, but switching to the very fine Rocky Mountain finned aluminum cover solved that right away.

I found cold-weather performance to be significantly improved with synthetic - less drag, easier shifting, the works. Very important up here. Runs cooler in summer, too.

Just my $0.02 - Ted

[JimCT]

red line shockproof will make your gearbox and transfer case seem as new. And works wonderfully in the cold.

[Escargo]

I'm no expert, by any means, just will tell you my experience. Initially was using Amsoil syn. and had lots of leakage from every box. Found GL-4 90wt in 5gal bucket for $60 and changed everything to it. My leakage decreased ALOT. Actually hardly noticable now. Can not feel any difference in gear shifting. Looks like you do not face the severe cold that all the guys in New England have. That probably makes some difference.

[TedW]

I'm no expert, by any means, just will tell you my experience. Initially was using Amsoil syn. and had lots of leakage from every box. Found GL-4 90wt in 5gal bucket for $60 and changed everything to it. My leakage decreased ALOT. Actually hardly noticable now. Can not feel any difference in gear shifting. Looks like you do not face the severe cold that all the guys in New England have. That probably makes some difference.

Gear lube turns to the consistency of rubber cement when exposed to severe cold - I know because I left a bottle out overnight once and then squeezed some out. Synthetic doesn't react the same way - it flows well even when cold, so it make a real difference up here. Down where you are: not so much.

[TeriAnn]

Gear lube turns to the consistency of rubber cement when exposed to severe cold - I know because I left a bottle out overnight once and then squeezed some out. Synthetic doesn't react the same way - it flows well even when cold, so it make a real difference up here. Down where you are: not so much.

Synthetic helps on the Colorado Plateau winters as well. It is also better at dissipating heat for those times I venture down South off the plateau into the Southern Arizona summer heat (all time record high for Flagstaff is 98 F)

[jac04]

It is also better at dissipating heat...
Agreed that syn oil has better heat transfer properties, but have you actually seen a decrease in transmission sump temperature as a result of using syn gear oil? Just wondering. The real limitation may be the ability of the gearbox to dump heat to the atmosphere, in which case the oil may not play such a big part.

[mearstrae]

Never checked the trans/transfer temps in my vehicle. But, in industrial use I have seen transmission sump temp drops as well as drops in motor amps using synthetics. A drop in amps needed would equate to less horse power used in a vehicle. (Now, some of these industrial transmissions held over 100 gal of gear lube.) So, less friction, less heat, less power needed. Oh, and we had fewer transmission failures when using synthetic lubes. Imagine the cost and work involved in rebuilding a transmission the size of a Series 88.

'95 R.R.C. Lwb
'76 Series III Hybrid 109
'70 Rover 3500S

[siii8873]

BTW Amazon sell gl4 gear oils.

[I Leak Oil]

Honestly, I don't personally know of ANYONE who can pin a transmission failure on using GL5. I've used mostly GL4\GL5 Valvoline for years with no ill results.
Not advocating one way or another but series have enough issues to deal with over and above fretting what oil to use.

Just avoid the limited slip stuff.

[TeriAnn]

Honestly, I don't personally know of ANYONE who can pin a transmission failure on using GL5. I've used mostly GL4\GL5 Valvoline for years with no ill results.


The failure would be the syncros going bad earlier than they would with a GL 4 lube.

[I Leak Oil]

Right, but again, I don't know anyone who can say with any certainty or prove that their sychro went bad, sooner than it would have because of the oil they used.
Again, I'm not advocating one way or another but seems like the religious use of GL4 might be more of a feel good measure than a practical one. If it's readily available then by all means go for it. Dumping a quart of GL5 in isn't going to turn your truck into a pile of parts overnight though.

[TeriAnn]

Right, but again, I don't know anyone who can say with any certainty or prove that their sychro went bad, sooner than it would have because of the oil they used.
Again, I'm not advocating one way or another but seems like the religious use of GL4 might be more of a feel good measure than a practical one. If it's readily available then by all means go for it. Dumping a quart of GL5 in isn't going to turn your truck into a pile of parts overnight though.

Nope. nothing happens quickly. And we don't have any scientific evidence on Land Rovers that I am aware of, but a lot of research has been done on the reactive sulfurs found in most GL-5 oils that causes damage to brass parts. Which is why everyone recommends against using GL-5 in older gearboxes.

If ya want to put GL-5 in your gearbox go right ahead. It is your vehicle.

[I Leak Oil]

ASTM D130 is one test a manufacturer can (and assume most do) put their product through to test the corrosiveness of it on brass based (yellow metals) parts.

Not everyone recommends against using GL5. Many modern oils used additives to eliminate or minimize any ill affects of sulfers. Some more modern gear boxes use yellow metals in conjunction with GL5 spec oils. In fact, not all GL5's are recommended for gear boxes. The GL rating is only one factor in making your choice.

You're safer going with an oil that is listed as GL4/GL5 rather than an older, straight GL5 product.

Lot's of debate about it on other car forums. At work, we have 50 year old stamping presses that have very large bronze bearings. When these were built it called for GL4 (I suspect this is why many older cars called for it specifically), primarily because that's what they had back then. Now, we use GL4/GL5 with no ill affects. I guarantee you replacing one of these bearings is far more expensive and complicated than doing the synchros in a series gear box.

[jac04]

... but a lot of research has been done on the reactive sulfurs found in most GL-5 oils ...

As far as I know, almost all major gear lube manufacturers are using non-active sulfur now. As I stated previously, the issue is typically not the EP additives attacking the yellow metal, it is the Limited Slip additives that don't work well with the syncros. And, again, even if active sulfur is being used, yellow metal attack does not take place at normal operating temperatures (yellow metal attack would happen at around 240F and above).

I work on worm drive industrial gearboxes that use bronze worm gears and specify the use of EP gear oil, so I'm quite familiar with the issue of EP additives and yellow metal attack.

[I Leak Oil]

That's a good point about the temperature activation component Jeff. I suspect if your gear oil is running at that temp for long periods of time you might have more to worry about than just the synchros!