Propeller shaft grease

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One symptom of a worn propshaft centre mount is what you described and is often worse on the over-run for ssomee reason when the rear diff/wheels are trying to drive the engine/gearbox rather than the normal state of affairs in a sort of torque reversal scenario.

thanks Grober, you have confirmed we are looking in the right area and it does look promising that this should resolve the issue.
 
Just had a check for my E350. Needs front and rear coupler. Both same part number, about £70 each. I would imagine similar across the Merc range.

Did you have any symptoms on your car or was this picked up on a routine check?
 
Did you have any symptoms on your car or was this picked up on a routine check?
Nothing wrong with my coupler as far as I know. I just checked the part number for price online, and as it's a part that will deteriorate with age, it's something I'd get done at the time whilst it's all apart.

I did have this changed on my 12 year old W203 320 petrol as there was a tiny bit of play.
 
Quick update, MB advise was to use any grease that met the 267.0 specification. A little surprised by this as this is a multi purpose grease.

I am going to use the grease below as I think it should last longer, it meets the specification mentioned by Grober and is suitable for splined shafts.

Mobil Mobilux EP2 NLGI 2 Grease 390g Cartridge Simply Bearings Ltd
 
Tech data sheet for chosen product here >> https://www.ulei-mobil.ro/pdf/MobilIndustrieDataSheet/Mobilux EP Range pds.pdf

For a high load application I'd look for a reasonable Timken OK load. Here it is 18kg (36lb). The grease I pumped into my steering joints last week has a Timken OK load of 70lb. It doesn't have MB approval though. Doesn't need it. I also had the option of a grease with a Timken OK load of 90lb.

I get the OP's need for a reasonable grease without having to buy in industrial quantity but my point is that for more severe applications there are greases available that are not commonly found through automotive channels.
 
Tech data sheet for chosen product here >> https://www.ulei-mobil.ro/pdf/MobilIndustrieDataSheet/Mobilux EP Range pds.pdf

For a high load application I'd look for a reasonable Timken OK load. Here it is 18kg (36lb). The grease I pumped into my steering joints last week has a Timken OK load of 70lb. It doesn't have MB approval though. Doesn't need it. I also had the option of a grease with a Timken OK load of 90lb.

I get the OP's need for a reasonable grease without having to buy in industrial quantity but my point is that for more severe applications there are greases available that are not commonly found through automotive channels.

Hello Bellow - Thanks for the useful information. Can you let me know the make and model of the grease that you used? I have ordered the Mobilux EP but that would not go to waste as it has so many uses.
 
Hello Bellow - Thanks for the useful information. Can you let me know the make and model of the grease that you used? I have ordered the Mobilux EP but that would not go to waste as it has so many uses.

This one here >> https://www.lelubricants.com/wp-content/uploads/pdf/flyers/3750-3752 Product Info.pdf is what I used.
Because, 70lb Timken OK load is just what highly loaded PAS needs, it is waterproof and wont wash out, being lithium complex it wont react badly with whatever was in there before (saves onerous flushing) and - well because it was already in the grease gun hanging on the wall!
(Penske used this at one time or another on its race cars - for suspension and steering IIRC).
 
Holy crap, spline lube is a worse topic than what oil to use!
There seems to be a great deal of controversy about the relative merits of moly grease and moly paste [ greater moly content] in the bike community but this content caught my eye which neatly summarises why spline lubrication demands may differ in many ways from more conventional applications.
"FYI, some dealers & mechanics assume that moly assembly lube (having only a few % moly disulfied, and a low temperature carrier 'grease') is equivalent to moly paste. Not true. Moly paste does not lose any appreciable amount of it's properties up to maybe 600 deg F because of both the moly disulfide properties and its relatively low fraction of the carrier 'grease'. Lithium doesn't provide the same properties as moly...it is has a lower temperature and lower load rating, and generally degrades quicker IIRC.
There is a difference between a CV joint (like splines) and a roller bearing. Specifically a CV joint or spline does not have flow or relative movement of parts, but a bearing does. In a spline, the same mating surfaces always stay together. In a bearing, the balls & races move relative to each other and there is continuous flow and blending of lubricant and air. So a little grease haphazardly applied in a bearing gets spread to the friction surfaces. But in a spline the initial lubrication of each mating surface is all that the mating surface ever sees. Hence, the flowing properties of the grease or paste matters--when using a paste it is assumed that it is properly lubricated on every friction surface during assembly, and that the lubrication (paste) stays in place during the entire service life."
 
Holy crap, spline lube is a worse topic than what oil to use!
There seems to be a great deal of controversy about the relative merits of moly grease and moly paste [ greater moly content] in the bike community but this content caught my eye which neatly summarises why spline lubrication demands may differ in many ways from more conventional applications.

Well, if we are really digging in to this, here are a couple more points.

"FYI, some dealers & mechanics assume that moly assembly lube (having only a few % moly disulfied, and a low temperature carrier 'grease') is equivalent to moly paste. Not true. Moly paste does not lose any appreciable amount of it's properties up to maybe 600 deg F because of both the moly disulfide properties and its relatively low fraction of the carrier 'grease'. Lithium doesn't provide the same properties as moly...it is has a lower temperature and lower load rating, and generally degrades quicker IIRC.

He/she is overlooking moly's role as an anti-wear additive for the unique condition of 'boundary layer' lubrication ie, when the film strength of the oil (which is also in grease) has broken and can no longer separate the two rubbing surfaces which would come into contact were it not for the anti-wear additive. If the 'lithium' he refers to (lithium thickened grease in reality as it is oil that is the lubricant) had sufficient film strength (the same as moly) then moly wouldn't be needed.

There is a difference between a CV joint (like splines) and a roller bearing. Specifically a CV joint or spline does not have flow or relative movement of parts, but a bearing does. In a spline, the same mating surfaces always stay together. In a bearing, the balls & races move relative to each other and there is continuous flow and blending of lubricant and air. So a little grease haphazardly applied in a bearing gets spread to the friction surfaces. But in a spline the initial lubrication of each mating surface is all that the mating surface ever sees. Hence, the flowing properties of the grease or paste matters--when using a paste it is assumed that it is properly lubricated on every friction surface during assembly, and that the lubrication (paste) stays in place during the entire service life."

No one would reasonably expect 'flow of grease' in a splined application. Proper application of the grease to all splines and retention - not flow - is what is required.
Splines suffer from stiction. Moly is noted for its stiction. One is an odd choice for the other. The reality is that moly is the best anti-wear additive available to most lubricant manufacturers and as splines are heavily loaded without the benefit of hydrodynamic lubrication (developed by parts having high degrees of motion relative to each other) and 'boundary layer' lubrication is a frequent occurrence, they have little choice but dose with moly.

Notably, Colin Chapman eschewed splined driveshafts for a long time as he was well aware of the stiction and how it could 'lock' the suspension under power.
 

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