Several members have had success with TransX for cleaning trans internals. Since you have varying degrees of engagement, as was mentioned earlier, it could be a pressure issue. You could drain or suck out a quart of fluid and replace with a quart of TransX or top off as needed if you have the dipstick. If you note a marked improvement, then follow up with a fluid and filter change, including torque converter. This is a straight forward DYI. Might be all that is needed.

If looking for a shop to rebuild, call around Sprinter van repair shops and ask whom they recommend. Sprinters have been using this trans from 2005-16 so there are a lot on the road. MB shops probably can recommend as well as Dodge repair shops specializing in SRT8 cars which also used them. You should be able to get some good recommendations.

If you trans is 1999 or older, you will likely need to replace the pressure regulator valve spring, they are a known issue on the older boxes

Mercedes 722.6 solenoid pressure regulator valve spring Sonnax 68942-01

Good luck

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Stable Mates:
1987 300TD 310K mi (Hans)
2008 Jeep Grand Cherokee OM642 165k mi (Benzrokee)

I've only tried using Trans X in one transmission during a transmission service on a 1995 E300. The transmission died within a couple of months.

Thanks for the link to the spring.

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Jim

Thank you, I appreciate it. It's worth a shot - at this point it can hardly get much worse. I'll also look up Sprinter shops, that's a great idea. Given weight of Sprinter vans those transmissions should be strong enough for my slightly beefed up 606.

Hopefully you will get some positive results. Best of luck.

As to the strength of the trans, no worries there, they are very strong, have a higher base torque capacity than the 722.3-4 and can be modified to handle up to 1000 Nm as done for several AMG models.

__________________
Stable Mates:
1987 300TD 310K mi (Hans)
2008 Jeep Grand Cherokee OM642 165k mi (Benzrokee)