Mercedes-Benz Forum - View Single Post - 722.6 Transmission Whine, will not move, no fluid pressure at cooler
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post #6 of (permalink) Old 02-13-2019, 08:44 AM
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Date registered: Feb 2019
Vehicle: 2004 S500 & 2006 E350
Location: Chicago, IL
Posts: 4
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Quoted: 1 Post(s)
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Originally Posted by 79Mercy View Post
Hey guys really need some advice if anyone has any to lend. The car in discussion is a 2000 E430, vehicle was purchased with what we were told was a failed transmission. Vehicle would drive normally for approximately 5 min, loud whine noise would appear and transmission would fall out of gear. Checked fluid level, found fluid level actually a bit high, now knowing it’s because the pump is not functioning

Some of the first checks were for oil in the harness, none found and control unit is dry.

No major metal particles were found in the pan and no abnormal amount of clutch material found.

Known good valve body installed with good conductor plate and good solenoids, problem still present. Same exact problem.

Removed transmission from vehicle and dismantled transmission. Inspected everything and checked clearances as per wis documents, nothing abnormal found. Front pump was found to be fine, bushing was ok. And no discoloration from heat was found. Trans was put back together with new Teflon seals and new alum hardware as stated in wis.

After replacing the Teflon seals and re assembling trans, vehicle drove for approx 250 miles normally, then without warning symptoms appears. Same exact symptoms. Whine noise, trans lost movement.

At this point i i stalled a known good 722.6 from another v8 car, same Trans and same torque rating. Vehicle drove fine for about 5 months, then same exact symptoms occurred on the replacement transmission.

Removed the pan and found coolant contamination in the atf fluid. Replaced the radiator, drained torque converter, removed valve body and cleaned. Put all back together. Vehicle drove for about 100 miles and then all of a sudden the same symptoms occurred again.

I removed the replacement Trans and inspected, only to find nothing out of the ordinary. Everything appears to be visually ok. This time i put in a new front pump assembly, because i was out of options at this point. After installing the new pump the transmission only operated for about 10 min before the same thing happened.

I can crack the cooler hoses at radiator and find NO flow with engine running.

If anyone has delt with this and found a cure please let me know. I’m out of options at this point. I believe it’s a mechanical pressure problem, as even with no control unit installed the vehicle should be stuck in 2nd gear, limp mode.

Any advice is helpful. Thank you.

Experiencing same problem with S500 and 93k. Have you found solution to that problem?
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