Hi Zakkk - my '99 E300Turbo does the same thing on shifting. It has 220,000miles, tons and tons of rust too. I've had the dreaded Spring Perch Failure as well on this car. The shifting problem is just as you describe - no up shift or sometimes it will upshift late and BANG into gear. After that all is well for a few weeks and it happens again. Maybe it is a vacuum problem? dunno...I'
ll drive it until it needs more attention.

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dtf
1994 E320 Wagon (Died @ 308,669 miles)
1995 E300 Diesel (228,000)
1999 E300 Turbodiesel ( died @ 255,000)
2006 Toyota Tundra SR5 AC 4X4 (115,000 miles) rusted frame - sold to chop shop
2011 Audi A4 Avant (165,000 miles) Seized engine - donated to Salvation Army
BMW 330 xi 6 speed manual (175,034 miles)
2014 E350 4Matic Wagon 128,000 miles
2018 Dodge Ram 21,000 miles