1999 E430 722.6 Transmission Failure:Rebuild, Replace or Part out car... - PeachParts Mercedes-Benz Forum

lou-in-nj · #1 01-03-2011, 10:35 AM

I have read several topics regarding the bearings that tend to go at around mileage of 120k on the 722.6 transmission which is right around where this car is now. I initially thought it was the torque converter bearing that is usually the culprit but after extensive reading of the forums here and other places it looks like it is a bearing on the main shaft which means an entire rebuild. I was weeks away from trading in this car but now the specter of $1000's to rebuild may just mean I keep the car another year. I would do it myself but it doesn't sound like it is as easy as a Chevy which I was usually able to drop a tranny out of in 90 minutes. Anybody experienced in a tear-down of this unit? Also, I'm not beyond parting out this car as it is only worth about $6k on trade-in.

How it came to pass:
The other day I pulled out fast from a dead stop to stay out of the way of an approaching car. I spun the engine to over 6000 rpm, I hadn't done that in years, and let up once I hit about 45mph. A day or two later I heard a ticking sound which I thought was the catalytic converter, two days later it suddenly turned into a rattling, grinding sound as I pulled into a parking garage. The transmission felt like it locked-up for a second but I was able to get into a parking space after about 200 feet of travel. I tried to put it into reverse but it bucked like the differential was locking-up. The noise and vibration goes away if spin the engine off idle to about 1200 rpm. Now I am faced with putting lots of money into a car I was only going to keep for another year. The alternative is to make it my winter project since I have other vehicles. I am going to tow it in a day or two, I would appreciate any meaningful advice on this advanced DIY project (I've done just about everything you can do on cars in the past 25 years so I am not afraid of this although this would be my first transmission rebuild if that is what it takes.) I look forward to your input or questions.

mbdoc · #2 01-03-2011, 10:53 AM

I'd try to find a good used trans for the car.

Rahulio1989300E · #3 01-03-2011, 11:23 AM

Well, if you said you were absolutely in love with the car and wanted to keep it for another few years than I would say go ahead and buy a good used (like M.B. Doc said) or rebuild it, but since you seem to be having a lot of problems with this car and you were getting ready to trade it in for something else anyways I would say that you should just part it out or sell it cheap.

Problems while owning '99 E430
Continual ABS/BAS problems.
P.S. pre-catalytic convert rusted out at 90k
Ignition key actuation problems.
Gear shifter shift gate issue.
Bad antenna amplifier.
CD changer.
Heated seats never worked.
Biannual air conditioning failure.
Power windows and moon roof.
Leaky valve covers.
Rear power window broke.
Poor rear lamp connections due to bi-metal corrosion.
Maybe my spring perches will fail someday!
Engineered like it's not a car

You are not happy with this car!
Why put money into it at all? What happens if the rebuild goes south?
I say part it out or sell it cheap.

Although, it is possible that the most fiscally responsible thing to do is to replace the trans with a good used unit and then immediately trade it in. This would save you the headache of trying to rebuild a different style of trans than you are used to and will get the E430 out of your hands quickly.

mbzman · #4 01-03-2011, 02:21 PM

I would cut you losses and sell the car for parts or as is, especially considering all the issues you have had to deal with. Just out of curiosity did the car receive regular transmission fluid changes?

lou-in-nj · #5 01-05-2011, 09:41 PM

The transmission received a fluid change at 80k. But I don't believe that service or frequency of it is the reason that bearing fails. From what I've seen, the filter on this tranny is substantial and effective. I remember GM filters that were little more than a bronze screen. I think this bearing and or its race or mount are poorly designed. All parts in contact with each other will wear, and how to maintain serviceability of components while clearances are changing through the life of the assembly is a matter of engineering. The fact that this bearing has now been substituted for a completely different design is evidence that the original part was poorly conceived when the factors previously mentioned are considered. Whatever I do it will be a major PITA. I have a trusted mechanic looking for a low mileage substitute. I see MB rebuild kits for less than $400, but that is if none of the planetary sets nor any of the other major components are damaged. Too bad Hyundi isn't offering one of those push your car in for $5000 trade-in deals, I might just go for it now! (Has anyone driven the V8 Genesis sedan?)

lou-in-nj · #6 01-20-2011, 04:02 PM

Found a transmission with 89,000 miles on it. It looks like everything from 1998- 2002 will fit my '99. Does anyone know if they changed the bad bearing design at some point and what year that would have been?