1992 500E - difficult to get reverse when hot

[Holeshot]

It's been getting a little worse and a little worse over the last few months and now.. it's really tough to get the trans to engage reverse after the first start of the day.

Forward gears all engage and work fine. Reverse, once engaged seems just fine, it's getting the transmission to that point that is getting difficult. I'll try to explain.

When hot, if I select reverse the trans will just sort of slip and whir.. like it's between gears, for a duration until it slips (engages) into reverse. If I gently throttle up/down until it drops into (engages) reverse it's OK. If I let it rev much more than 1000 RPM when it does engage reverse it 'slams' into reverse with squeeling tires and all the fun and violence one would expect from a good old-fashioned 'neutral-drop'.

This is becoming a major drivability issue. It needs to be fixed but, who to trust in Washington to look after said transmission (be it a re-constitutio of the valve body or a full-blown rebuild). I posted in the regional form with no feedback.

Should any reputable transmission shop be able to service this transmission? Honestly? I had a the trans in my 300E rebuilt by and Indy shop and it worked just fine. I don't live down there or I'd just take it to them again. The dealer quoted about $5500 to R/R and rebuild trans... ouch.. last time I had it done in CA it was under $2400 in and out.

Then there is the question of what the problem with the trans might be? Sticking valves in the valve body? Simply needs a trans oil change and fitler maybe or the trans is hosed and a rebuild/replacement is required.

Looking for suggestions. Right now I'm renting a place in the city (Seattle) and I do not have my big heated garage to work/diagnose in so I'm at the mercy of mechanics to get this resolved.

Help!??!