[burqueDOKA]

Hello all, I'm looking for some guys who have been around a while to clear up some pretty wide spread misinformation on Non-Hypoid gear oil. MB says to only use Non-Hypoid gear oil in your unimog transmission. Now a lot of people don't even know of the existence of Non-Hyupoid oil much less understand what it is and why it should be used over regular 90w. The other problem is it is not easy to find the stuff. So, my question is how important is it really to be using the stuff in our trannies in this day and age of syn oils? And if it isn't, who's had good luck w/ what gear oils in their trannies?

 

[Andrew]

I had saved this information, this guy is so thorough that it needs no more explanations:

From: [email protected] (Andy Dingley) Newsgroups: rec.autos.tech Subject: Re: Hypoid vs. Non-Hypoid Date: Tue, 09 Jan 1996 17:45:49 GMT Mark <[email protected]> wrote: >Can someone explain the difference between Hypoid and Non-Hypoid >oil? "Hypoid" is not really a question of oil, so much as a question of gearcutting. Old (1920's) rear axles used straight bevel gears to form the crownwheel and pinion. These had two disadvantage, the pinion shaft meets the crownwheel on its central axis, and the straight cut gears are noisy. By using a more complex "hypoid" gear tooth shape (if you look at a pinion, the teeth appear twisted) these problems can be addressed. The more gradual engagement of the teeth along their length reduces noise. By careful design of the geometry the pinion can be made to mesh _below_ the axis of the crownwheel. As the centre height of the crownwheel is fixed by the wheel height, this allows the propshaft to be lowered relative to the car body, giving a clearer floorpan and lower centre of gravity for better cornering. Hypoid bevels are now universal in this application. Because of the sliding contact that hypoid gears make, their hydrodynamic contact pressure is higher. To be suitable for use with hypoid gears, a lubricant must be capable of resisting high pressures. Oils with "EP" ratings (Extreme Pressure) such as EP90 are required. Some brands describe themselves as "hypoid" instead, a term which is synonymous with EP. GL-5 is a formal API standard for this type of oil (comparable to MIL-L-2105B/C/D) > The book is telling me to use Non-Hypoid gear oil 80W or >80W/90 on the manual transmission and GL-5 hypoid gear oil 90W on >the rear axle. A manual transmission won't usually contain hypoid gears, so it doesn't need an EP oil. Rare exceptions are those transaxles where the crownwheel and gearbox share the same lubricant. Although an EP oil is more complex to manufacture, it has no disadvantages when used in instances where the EP attribute isn't strictly required. Manual steering boxes and other slow-moving oil-containing components are often filled with 90 weight oil. It's usual to buy EP90 because that's what the axle requires, then use the same oil for all other components. There's little practical difference between 80 & 90 weights. I fill everything with EP80 and I've never had a problem. There's an increasing trend amongst manufacturers to reduce the number of different lubricant types required. My own gearbox (5 speed Range Rover) runs on ATF, but 20W/50 engine oil or EP90 axle oil are equally permissible. -- Andy Dingley [email protected]

 

[Mogasaurus]

One thing I know about the Mog transmission is that you need to run GL4 rated lube. Not GL5.

GL5 has much higher concentrations of EP additives that can attack the "yellow metal" (bronze/brass syncro's, ect) components of the gearbox. See point 2 of the FAQ at http://www.pennzoil.com/site/faq.html

An excellent GL4 rated trans lube is REDLINE MTL. I run it in the gearbox of my Rover with superb results and will be putting it in the 416 box at the next change.

 

[Fizz]

That goes for the gearbox, axles and the hub reduction gear? [?]

Mogasaurus - 4/3/2005 2:56 AM

One thing I know about the Mog transmission is that you need to run GL4 rated lube. Not GL5.

 

[VMog]

Fizz - 4/3/2005 12:47 AM

That goes for the gearbox, axles and the hub reduction gear? [?]

Nope just Tranny/gearbox. no yellow metals in axles and hub reduction gears.

 

[Fizz]

In the "book" it says that the axle´s, and hub reductions (and gearbox) should hvae a straight 90W gear oil, but i cant find any. Its all 80-90W GL-4/5 oils out there ... Works fine, or what? []

VMog - 4/3/2005 7:29 AM

Fizz - 4/3/2005 12:47 AM

That goes for the gearbox, axles and the hub reduction gear? [?]

Nope just Tranny/gearbox. no yellow metals in axles and hub reduction gears.

 

[Crashmaster]

It is the sulfur compounds in GL-5 that can harm the yellow metal components

 

[Dangerous Dan]

I've heard that the EP additives do attack yellow metal but only if the temp of the oil goes above 200 degrees F.
I'm using Mobil SHC 1000 in the hub reduction gearboxes with excellent results.
I changed the gear oil in the transmission to Valvoline synthetic gear lube. My opinoin is this stuff is junk. The truck was harder to shift after changing it. Try the Redline MTL I have had good results with it but it is very thin and intended for high speed. Some transmissions I have put it in got alot louder since the oil is much thinner but they all shifted better. Redline also makes Shockproof, similar but a little higher viscosity. Another oil I like for transmissions that is a little heavier than The redline oils is VP Fuels GL-100 and GL-150. I feel it is better suited to a slow spinning Mog transmission since the viscosity is higher giving better protection at low speed with high torque.

 

[Fizz]

i did a quick google search for "Mobil SHC 1000" and accordingly to Mobil its an oil designed for air compressors?

 

[volksmog]

Hypoid oils are oils in the grade from GL4 and up. GL1,2,3 are non hypoid. We did in the netherlands also a check and asked some oil manufacturers about it. GL4 hypoid oil is the one that is made to MB specs. A lower GL class can cause damage because specs are to low (heat, to less lube, early aged oil) To high GL, 5 and up, has more additives that as told can affect the "yellow" parts.

So for oils look into the original specifications from MB and the comparity of the new oils made to those specs.

I use KROON-OIL, think a dutch manufacturer?

http://www.kroon-oil.com/uk/product...s&makeid=40270&rangeid=402701000&modelid=4825

 

[esde]

Is this the Amsoil gl4 synthetic that Jack was recomending? http://www.lubeus.com/agt_80W-90_lower_unit_Gear_Lube.php It's the only one that I can find. Thanks, Seth

 

[Dangerous Dan]

[]

 

[DDBCretin]

Hey everyone, first post.

It's my understanding that the GL-4 spec had a requirement to protect yellow metals that is not part of the GL-5 spec. If the oil in question is rated MT-1 then it has additives to protect yellow metals. Mobil 1 gear oil and Schaeffer's 267 (just to name two) are both rated GL-5 and MT-1. I'm using Schaeffer's in my 404 tranny right now, but it's not been in long enought to evaluate. []

 

[Ragnian]

I know we have some AMSOIL dealers in our Unimog forum....

Is AMSOIL Synthetic Manual Transmission & Transaxle Gear Lube compatible with none synthetic GL-4 gear oils?

I think I found my oil leak transmission has a VERY slow leak...just want to top it up for now....they have this stuff at the local Napa Auto Parts.

Attached PDF is from AMSOIL website

 

[stevesmog]

Yes, That's the one you want!

AMSOIL Manual Transmission & Transaxle Gear Lube 75W-90

 

[Ragnian]

stevesmog, thanks!

I figured I would ask before I poured a quart into my transmission with non-synthetic oil. Glad it will work

 

[unirover]

As others have mentioned, in the past GL-5 rated gear or hyping oils contained additives that could attack yellow metals. More specifically - sulfur. With heat and time the sulfur creates sulfuric acid which can attack the yellow metals. Nowadays most GL5 does not use sulfur but some may. Most GL5 also has friction modifiers for limited slips. The main reason to use GL4 over GL5 is that they are different type oils designed for different type applications. The GL5 is designed for non synchro, high pressure gear set ups. GL4 is for synchros and no limited slips. Basically GL5 is slipperier than GL4 which sounds like a good thing except the synchros actually need a little friction to function optimally. They also have different shear and cushioning requirements. GL5 is not higher spec than GL4, it is a different spec so they are not backward compatible. I've seen synthetic gl5 that says it is gl4 compatible but I am skeptical since they have different performance parameters. I think there are a few Amsoil GL4 spec oils (just make sure they are GL4 not 5) and many on the list are very happy with it. I think the closest oil widely available in the USA that matches Castrol Syntrans is Redline MT-85 which is what I use when I can't source the Syntrans. I think the Redline even has Mercedes approval.

 

[tmodler]

I have just replaced my Amsoil MTF with the Redline MT-85, and UNIROVER mentions and JP helped to facilitate (Thanks again!).

I am happy with it. It is very different, but the gearbox shifts more like I think it should (better is a very subjective term) and the closer spec match makes it an all around winner.

C.

 

[DokaTD]

I have to say so far Amsoil has made my truck shift worse. I'm still waiting to make full judgement but it was a clear and different shift. Made getting into any gear cold very hard. Frustrating after all the hype.

 

[tmodler]

I am not sure there is a "right" solution for all SBU gearboxes, they really seem to vary a lot. RP was better than Castrol for me, then Amsoil even better, not this redline seemes to be a good balance between the two. The RP stuff is too thick, Amsoil too thin, Redline: Goldilocks. At least IMO, and based on about 1100 km on the Redline...

C.