Joris Posted December 6, 2005 Share Posted December 6, 2005 What gearbox oil would you reccomend me? I've drained it all and I want to clean it up with parafine (sp?) and then put new oil in, but what to get? It's for a Dodge WC 51 but I think type does not matter much in this subject. Quote Link to comment Share on other sites More sharing options...
M8Greyhound Posted December 6, 2005 Share Posted December 6, 2005 Gearbox oil for a WC Dodge is EP90 Hypoid is ONLY for rear axles.......:-) Regards Lloyd Quote Link to comment Share on other sites More sharing options...
Karoshi Posted December 6, 2005 Share Posted December 6, 2005 There is much misconception about Hypoid and Extreme Pressure Oils, the following may be of help; "Hypoid" is not really a question of oil, so much as a technique 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) Quote Link to comment Share on other sites More sharing options...
Mark Posted December 6, 2005 Share Posted December 6, 2005 I like that Karoshi, But what oil is suitable :?: Quote Link to comment Share on other sites More sharing options...
Richard Farrant Posted December 7, 2005 Share Posted December 7, 2005 But what oil is suitable :?: Going by the manual it would be SAE 90 gear oil, do not confuse this with SAE 90EP. The later has extreme pressure additives which can eat into bronze and brass. Often refered to as a "straight oil", SAE 90 is best for jeep gearboxes as the use of an EP oil, hampers the braking action of the synchros, by the EP additives doing exactly what they say on the tin. Richard Quote Link to comment Share on other sites More sharing options...
Joris Posted December 7, 2005 Author Share Posted December 7, 2005 Thanks I'll start looking for EP90. Quote Link to comment Share on other sites More sharing options...
Richard Farrant Posted December 7, 2005 Share Posted December 7, 2005 Thanks I'll start looking for EP90. Mad Man, Sorry, you misunderstood my message. The gearbox should NOT have EP90 in it, because I believe there are bronze bushes in it and the additives in EP oil eats into them. The correct oil is SAE 90, what we would call in the UK, a "straight oil" There is a distinct difference between the two oils. Richard Quote Link to comment Share on other sites More sharing options...
mick garner Posted January 14, 2006 Share Posted January 14, 2006 we bought some straight sae 90 from a company that specialised in lubricants for historic vehicles, cant recall their name but you'll find one in a classic car magazine. boy just told me its called millers lubricants-clever blighter! Quote Link to comment Share on other sites More sharing options...
Richard Farrant Posted January 14, 2006 Share Posted January 14, 2006 we bought some straight sae 90 from a company that specialised in lubricants for historic vehicles, cant recall their name but you'll find one in a classic car magazine. boy just told me its called millers lubricants-clever blighter! Mick, Another good source of oils for historic vehicles is Morris Lubricants. They even make oil for steam engines. Richard Quote Link to comment Share on other sites More sharing options...
Centurion Posted January 15, 2006 Share Posted January 15, 2006 Well I was a bit confused before and Im not sure that Im any wiser now or perhaps Im just thick. I have the Pat Ware book on Hotchkiss 201,s and in the part on maintenance the recommended oil for gearbox and transfer case is hypoid 90ep. If the vehicle is a licence built MB does this mean that the book is wrong and that I should use sae 90 only. I have some semi synthetic sae 90 gear oil in my garage could I use that. Any comments on this dilemma will be greatly appreceiated Centurion Quote Link to comment Share on other sites More sharing options...
Richard Farrant Posted January 15, 2006 Share Posted January 15, 2006 I have the Pat Ware book on Hotchkiss 201,s and in the part on maintenance the recommended oil for gearbox and transfer case is hypoid 90ep. If the vehicle is a licence built MB does this mean that the book is wrong and that I should use sae 90 only. I have some semi synthetic sae 90 gear oil in my garage could I use that. Cent, The M201 gearbox is no different to the WW2 ones, in that they have synchros. Any EP or Hypoid oils have additives that inhibit any friction and that is what a synchro relies on, friction. It is a brake ring to slow the gear down in order to mesh quickly. The original US manual calls for GO, which is plain 90 gear oil, save the EP90 for the axles and transfer box. Just shows you cannot rely on what is written in books Richard Quote Link to comment Share on other sites More sharing options...
Karoshi Posted January 15, 2006 Share Posted January 15, 2006 I'm with Kewelde, on this, but hell I just had a pasting on the Gee for daring to say the same. Still think Straight 90 is the better way to go. (Didn't want to say correct way, scared now) Quote Link to comment Share on other sites More sharing options...
Degsy Posted January 15, 2006 Share Posted January 15, 2006 I agree with Kewelde and Karoshi on this, trouble is too many people don't know the differences and the properties of these oils. There has been a huge leap in technology since these vehicles were built that a modern oil of any type is far superior to the oils of years ago, Morris Lubricants have an excellent web site which is well worth a visit and I would recommend their products after many years experience on a huge variety of vehicles and plant. Cheers Degsy Quote Link to comment Share on other sites More sharing options...
Centurion Posted January 15, 2006 Share Posted January 15, 2006 Thanks for that where I was getting confused before was it recommended the same oil for gearbox and transfer case but its ok to put ep90 in the transfer case but the gearbox should have sae 90 because of the synchromesh. cheers centurion Quote Link to comment Share on other sites More sharing options...
Richard Farrant Posted January 15, 2006 Share Posted January 15, 2006 I'm with Kewelde, on this, but hell I just had a pasting on the Gee for daring to say the same. I just took a look at G503, that guy is a bit of a ****, the original spec was GO which is straight 90. You will find Graham at Jeeparts recommends Straight 90 as well. As for a flying M series truck, what has that got to do with it? Does he want a medal, or should it be wings?? Richard Quote Link to comment Share on other sites More sharing options...
Karoshi Posted January 15, 2006 Share Posted January 15, 2006 Mum said to never argue with anyone less intelligent than youself, so I let it go. It just wasn't worth the effort! Karoshi Quote Link to comment Share on other sites More sharing options...
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