A 2008 Mercedes Benz C 300 came into the King Transmission Company shop in Elmhurst Illinois where Max Deese had to repair a noise problem with the transfer case. The owner works for the airlines traveling frequently so the vehicle had only 14,000 miles on it. The dealer wanted 5500 to fix the problem since it was “out of warranty.” This may not seem like a good deal but a new complete unit according to Alldata lists for approximately $8500 dollars. Still, the news made for a very unhappy customer. So he found his way to King Transmission Company.
This vehicle is fitted with a 722.9 transmission which the case is designed to include the AWD 4Matic transfer case. This AWD transfer case is contained by a rear cover and an intermediate housing that attaches to the rear of the case. Inside, there is a gear that spline onto the transmission’s output shaft called the transfer case’s drive pinion. This drive pinion meshes with another gear called the differential side gear used to drive the front axle propeller shaft (front drive shaft). This drive pinion gear also drives a planetary carrier and ring gear with intermediate shaft. This assembly is used to drive the output shaft to the rear wheels. There is a guide sleeve and shim on the transmission’s output shaft to align drive pinion to the differential side gear and rear planetary system. Care must be taken to not loose these parts.
The noise the customer was complaining about was a low end growling noise that was most prevalent during turns. When Max removed the rear cover, the planetary system and the intermediate housing, he saw the outer race for the differential side gear’s pressed bearing badly galled. The rollers in the bearing cage were badly pitted as well.
Max pressed the bearing off of the backside of the differential side gear and compiled both the bearing and bearing race part number. The outer race was NP312842 and the bearing was NP925485. Both of these items had the word “France” printed on them as well.
Upon ordering this bearing from the dealer, it was discovered that this bearing is not sold separately by Mercedes. Since the transfer case is part of the transmission, the dealer will be more than happy to sell you an entire unit. Probably for more than what they were going to charge the owner.
This was not good news for King Transmission especially now with having the unit out and apart on the bench. So they called around and learned that this bearing is not available here in the US. It is a Timken bearing only available in France.
If you have seen the movie Midnight in Paris, the theme is that Paris in the morning is beautiful, Paris in the afternoon is charming, Paris in the evening is enchanting, but Paris after midnight ….. is magic.
Well there was no magic going on at King Transmission Company and it caused some to be up well past midnight.
They eventually found a parts company that found a source in France that was willing to send the bearing over so they ordered two, one for the job and one for stock. When the 80 plus dollar order arrived (figure 14), a deep breath of relief blew some papers off of the counter.
A great heads up should one of these roll into your shop with a low end growling noise on turns coming from the transfer case. Be sure you have a “French Connection.”
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