save your money

[maybach]

Hi all

Just a friendly word to help with the running costs.

Reading through several posts it would seem that a lot of guys are spending money having the oil and filter changed on their 722.6 gearbox. (Fitted to most rear wheel drive M.B?S since 96 ish)

The oil developed for this box is good for the life of the transmission and does not need replacing. This comes from M.B and is not an old workshop tale. I think piestre will back me this one.

There are a lot of old school Techs who say that it is a good idea to change the oil, but oil technology has moved on in huge leaps, the same technology that allows us to go up to 18k between engine oil changes.

 

[simon]

This subject has been discussed in detail & at length here(Look in archives). with regard to premature failures in the 722.6 gearbox.
Inputs from individual & trade sources indicated that an oil change, prior to the onset period might well be advantageous.
The oil is expensive but could offset the four figure sums that some owners have had to face, following failure.

Ernest Sidesman

 

[maybach]

Thank you Earnest for your reply.

I have had the pleasure of meeting a gentleman who is the authority on the722.6, Mr G Shultz who was the chief design engineer for this transmission.
The oil used in the 722.6 does not loose it?s viscous property and no matter how dirty or smelly it becomes the oil can still do it?s job.
My purpose as a professional who works on Mercedes every day is to pass on a little info that may save people who do run their cars on a budget a little money.
Not bad for someone who works in a stealership

 

[GregE240]

Maybach,

I think you are right in what you say, but surely over the course of time metal shards and the general muck of wear and tear will take its toll on the transmission oil?

I don't doubt the viscous properties and the longevity claims that you make (all valid I'm sure) but there ARE documented premature failures of this gearbox.

What I would doubt is that M-B refusing to honour a warranty claim on such a failure. If it was indeed dirty oil that was the culprit then they're not going to contradict themselves, are they?

I would have thought for nothing else but peace of mind its a good thing to do. I'm still thinking of having mine replaced at my next service. But, I shall take Mr Gayle's advice on the matter (81K on the odo)

Kind regards,

GregE240

 

[Spike]

As far as my understanding goes, the fundamental frictionless properties found in oils are due to the structures of its polymers.

The design of a gearbox (meshing gears) is perfectly suited to 'cutting' these polymers up and changing their basic structure - thus reducing performance.

Now maybe the design and tolerances of the gearbox allows for a certain amount of wear but there is no way that old gearbox oil will perform as well as new.

Call my cynical but some of us could argue that it is not really in the interest of MB to make the car to last forever. If they did, they wouldn?t sell so many new cars. Perhaps by not changing the gearbox oil and by dictating very long service intervals etc, it reduces the life expectancy of the car to a level that MB are happy with....say for example around 300k trouble free miles or something. You may argue that 300k is perfectly acceptable but some people average 80-90k per year meaning that the car will only suit them for 3 years or to put it another way, just outside of the warranty period.

My choice would be to spend the money on the oil changes and have a *very* long lasting car.

Oil is cheap, gearboxes are expensive.

 

[Andy]

Hi All

My My we are getting technical "polymers"? All I can say & Maybach I don't doubt what you say. Having worked on these vehicles for some 25yrs 14 of those being with a stealership. I have seen MB promises of things that will last and no need to change this. But in the real world, the reality is totally different. Personally I have looked at the oil and maybe under a microscope its ok. But to my eye. I won't chance it. Its like Mobil 1. They say it lasts some 20-25k. But have that get out clause. "Should be changed in line with manufacturers recomendations"

Axle oil under the new service intervals (if memory servs) does not have to be replaced.But axle oil does deteriate and can cause problems.

So do we change the oil & filter in the gear box and save some money?????

If MB would pay for any damage caused. Hell no!!(To many American films!!) but they won't so untill its proved catergorically that the oil even though it looks like soup isn't going to cause a problem. Then I will still recommend a change of oil. But I do not insist that my customers or anybody on this forum change there gearbox oil in these 7226 boxes. But at least our viewers can read the posts and make up there own minds.

The fact that you Maybach have started this post from a different stand point and with true knowledge only helps those viewers who drive the marque to continue to contribute and make more informed decision.

I hope you and Piestore continue to contribute as I as well as others find your contributions of interest.

Regards

Andy @ www.mercedesservicing.com (of the ole school, but still willing to listen)