Land Rover gear oil?

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ccdhowell

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I'll try not to ask one of those annoying "what should I use questions." I have a '02 Land Rover Discovery that I use Redline 75W90 gear oil in the diffs and t-case. The viscosity is as per manufactorers specs. I need to change my gear oil soon and have become disillusioned with the RL motor oil and thought about alternatives for the gears as well.

I looked on the AMSOIL site and, though I'm not confused, I was wondering: I like the Severe Gear 75W90, but maybe I could get away with the 75W140 for added viscosity and protection. I live in Louisiana and don't see cold temps. I off-road this vehicle hard 6-7 times a year and wanted the best protection. I have stock differentials, ie not lockers or limited slips.

I looked at the Schaeffer's site, seems like folks like the Schaeffer's gear oil, but the site is not very helpful, no info to steer me into buying it.

I thought there would be a product that might reduce friction, thus improving mileage and wear protection. I couldn't find anything that jumped out at me. I RL may be the best for my application. Protection first, mileage second.

I wanted a word from Pableo and a Schaeffer rep, sorry don't remember a name, to chime in and straighten me out on gear oil for my Rover.

Anyone else have any opinions? I hate to say "cost is no object", but realisticly if I spent $100 bucks or more on this gear oil, I change it only once a year so I really wouldn't get concerned. That might spur some special blenders into the topic.
 
Thanks for chimming in Bruce. I have read your posts in the past and value your knowledge. I quessed from a previous post of yours that you would believe that way.

With a heavier oil should I expect less gas mileage? Could I ecpect greater shock protection during my off-road forays?

Thanks.
 
MolaKule, I looked at HDS-R and was turned away by the racing refernce. I normally consider racing fluids not to cantain the cleaning capability required for street use. Also on your site, you call it an intermediate weight and I don't know exactly what that means. If you say its good, then I'll order some soon.

I was considering your product for my Jeep T-case. It is an all wheel drive t-case with clutches. Jeep recommends ATF+4. I know thats not the best fluid. I thought I might use your MTFGlide. Jeep says to add their Limited Slip Additive to the case because of the clutches. Will your product be compatable with the friction modifiers?

Thanks.
 
"With a heavier oil should I expect less gas mileage? Could I ecpect greater shock protection during my off-road forays?"

Mileage may suffer yes on papper but I do not think you could messure it.
A higher vis >90 grade useing no VII will offer better shock and wear protection than any VII 75/90 or 75/140 oil.
I was told by the formost gear expert that gears do not "see" VII oils and as such it the base oil is a thin 30wt or so thickened to 90+ the gears will act as if running in a 30wt not the best for wear, spalling, pitting etc.

Again use a non VII >90wt such as a syn 75/140.
bruce
 
There you are. I agree Bruce and thanks.

MolaKule, does HDS-R have the aforementioned VII? I would think not.
worshippy.gif
 
Remember that Land Rover diffs aren't very hard on oil (they are spiral beval, not hypoid), although they are known to shear pinions and spit out cross pins when larger than OE tyres and lockers are used.
A very good 75w-90 that can take shock loading is nice in the LT230 t/case due to the coarse spline used on the input shaft that can wear quite badly. Mostly this has been overcome post 96-97 with the cross drilled input gear, but it is still heard of. Some local Land Rover specialists use R/L Heavy Shockproof here, although I think this is overkill.
 
The SVG 75W-90 is what is recommended and will work great in your Land Rover and has no VII. I actually disagree with Bruce in this case, TDI-Rick is pointing the right direction. A thicker oil is probably better for straight shock protection, but in some diffs does NOT show lower wear, and the resistance to flow of a higher viscosity is a detriment, not a benefit.
 
Tdi-rick makes good points that follow along with my Land Rover experience.

Spiral bevel diffs don't really need a strong EP oil. 'Wheeling, you'll bust an axle shaft before anything else. Or blow out the spiders. Come to think of it, I've grenaded my share of Rover diffs and seen many others and I don't remember a one relate to lubricants. Busted axles, blown spiders or crosspin, a sheared off pinion shaft or two, a chipped crown or pinion tooth, sure. Anecdotal? Yep, but I had pretty broad exposure: 20 years of my life as "Mr. Land Rover" with the underwear to prove it (factory trained Rover tech, LRNA off road driving instructor and on staff at LRO and LRM magazines for 10-plus years). I saw a lot of Rover related stuff and got to tinker a lot.

Depening on the type of 'wheeling you do, you may want to worry about water. Yeah, Rover diffs let water in as well as oil out. It used to be common knowledge that synthetics didn't deal with water all that well. I'm not sure that's still true or to what extent. It's still being claimed. I changed the gear oil in my Rovers at least once a year due to water ingestion.

There are issues with the LT-230 center diff that are lubricant related and the input shaft issues tdi-rick mentioned. The spline issue was lack of lubrication. The units were assembled dry and no lube could get in there after assembly, so the splines wore. The drilled gear solved this. So did an application of heavy grease at assembly.The center diff issues are largely driver related. Simply don't 'wheel in hard stuff without locking the center diff and you won't have a problem. Get stuck with the center diff unlocked, spin the one tire and whizz that center diff up... you'll burn up the oil in the tiny little center diff in half a minute, spit out the brass shims and/or bust the spiders. A better lubricant could probably resist this longer, but still you need to use the cranium.

My advice is to not get real excited about the diffs. Use up what you have in there now and when you change it next time, don't feel like you need to go high dollar or super whiz-bang. Personally, I think a 140 would be uneccessary overkill, but besides a slight increase in frictional hp loss, there's no harm in it everyday. You just aren't going to gain anything tangible, IMHO.

The term "shock loading" is a large part marketing hype IMHO. At least in the four-wheeling world. Any good 90 offers adequate boundary protection when used within it's oil temp limit. You don't often generate really high gear oil temps four-wheeling, so you aren't going to "French fry" the oil and weld the gears together like you would towing over the Rocky Mountains. A 140 is more for when the going gets the oil really hot... say sustained over 200 degrees. A Rover diff would run particularly cool in all situations because its a spiral bevel rather than hypoid.

The t-case is has brass in it, so take care using GL-5 EP oils with strong SP add packs. Most are stable, but.... do you trust them to stay that way? There are good GL-4s too and GL-5 oils that use alternative EP packs rather then SP. I used to use a BG product back when, but I don't recall the name of it. It'd be old news today anyway! I'd consider a very good synthetic GL-4 75W-90 in the t-case.
 
Thanks guys. Good to here from a Land Rover guy, Jim. My 2002 Disco doesn't have the CDL so I wheel relying solely on the traction control and a measured throttle. So far, so good. I don't, not yet at least, ford water crossings so I haven't worried about water ingress. My conditions are very dusty and I do worry about sand getting into the diffs through the vent hoses. I think I'll try the product from MolaKule. Sorry Pableo.

Thanks to everyone.
 
ccdhowell, some specialist companies, at least here in Oz offer a CDL retrofit for your Disco. Well worth investigating if you wheel a bit. It's worth noting that the Defender with TC and the LT230 still had a CDL during the years it was dropped on the Disco.
 
quote:
Yeah, Rover diffs let water in as well as oil out.
Click to expand...
convert the post '92 hubs from grease to diff/axle oil lubed by removing the inner axle seal and using an RTC 3511 hub seal virtually eliminates this.
wink.gif
 
ccdhowell... Your Disco has the center diff, just without the means to lock it. From what I understand, all you have to do is get the parts from the earlier rigs that had the lock and install it. That was all a bit after my time, so I don't know the nitty-gritty details.
 
quote:
The term "shock loading" is a large part marketing hype IMHO.
Click to expand...
Actually, shock loading is another name for "Mechanical Impulse," and graphically, it appears as a sharply rising mechanical force whose amplitude rises fast with respect to time.

Shock loading can be seen in highly loaded valve train components, in knock or preignition, and torquewise, when at the starting line the clutch is let out and you "let 'er rip."
 
quote:
MolaKule, I looked at HDS-R and was turned away by the racing refernce. I normally consider racing fluids not to cantain the cleaning capability required for street use. Also on your site, you call it an intermediate weight and I don't know exactly what that means. If you say its good, then I'll order some soon.

I was considering your product for my Jeep T-case. It is an all wheel drive t-case with clutches. Jeep recommends ATF+4. I know thats not the best fluid. I thought I might use your MTFGlide. Jeep says to add their Limited Slip Additive to the case because of the clutches. Will your product be compatable with the friction modifiers?
Click to expand...
A mid-viscosity differential fluid refers to the fact that it is about 23 cSt@100C which is beteen a 75W90 and a 75W140. It contains the same detergents and dispersants as our other gear lubes. In fact, it has a higher level of detergent because the detergent also moderates shock loading.

I think you may be referring to Racing Motor oil which has low levels of detergents and dispersants.

The MTFGlide has friction modifiers for sychros and clutches in TC's.
 
Thanks for the description and explanation, MK.

I meant "marketing term" in the sense of hyping a characteristic not all that necessary in the four wheeling realm. Correct me if I am wrong here, but if the oil is running at a temp below where it will get excessively "thin" due to heat, is not a 90wt adequate "Shock" protection? And don't the EP additives (whatever they are) play a part as well? Most axles run from .005-.020" backlash (many at or below .010"), so it has only that far to build up the "mechenical impulse." A gob of 90wt at it's rated viscosity should be fine to provide a "cushion" should it not?

Anecdotally, I have observed in 31 years of four-wheeling, and being embedded into that realm up to my nostrils professionally, that ring and pinion problems (where the R&P was the "chicken" and not the "egg" of another part failure") are quite rare. Contrast that with motor homes, trucks and towing rigs, wher R&P failures due to heat and cooked oil are fairly common. I have monitored off road diff oil temps on some of my own rigs over the years at different times and in different ways, as well as taking note of other who have also done so, and the temps typically don't rise past 150 degrees. There are exceptions, most notibly in axle with large hypoid offsets.

I firmly believe a 140 is a good choice for a tow rig, but I see no benefit to it for a four-wheeling rig.

In any case, if I am off base in my supposition on shock loading, educate me thoroughly and I'll have my earlier comments between some bread, layered in lettuce and lathered with horseradish posthaste! Yumm!

Hopefully this thread didn't get too cold while I was too busy to answer to get a reply!
 
Jim, I actually appreciate your insight here. Interesting that the t-case is the unit that builds the heat. Would you say it is enough heat to spur the need for a really good gear oil?

I understand that the diffs aren't going to build lots of heat in an off road situation. People that aren't familiar with the 2mph adrenaline rush of four wheeling and its particular abuses to the vehicle may not understand completely.
 
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