I have recently started driving my 87 300D and have noticed when you let off the accelerator the car slows fairly quickly; however if you shift it into neutral it will coast much farther. also the 2-3 shift will not happen when it is supposed to unless you let off on the accelerator slightly. any thoughts?

Maybe you're used to a locking torque converter.

Don't shift into neutral above 30 mph.

Your control pressure (Bowden) cable might need adjustment or might be sticking.

Sixto
87 300D

thanks ill look into it.

Just curious here, but why?

I believe it has to do with the front pump on the transmission.

The front pump doesn't lubricate the transmission sufficiently or at all in neutral. The rear pump, if still installed, has limited lubricating ability.

Sixto
87 300D

does this apply to W123s too?

__________________
1985 300d champagne/palomino ~133k
1979 300d dead parts car ~???

It sounds like you have an issue with the vacuum control system. You feel engine braking more when you're in too low a gear. If it were in the next higher gear, engine braking would be less notice-able.
The vacuum control system is a separate issue from the bowden cable, which is responsible for heavy throttle forced downshifts. Teh vacuum setup is responsible for timely upshifts. Peruse the DIY articles in the Resources section for info on troubleshooting the transmission vacuum control system. The W123 stuff should apply to your car too.

Yes. Applies to 722.3 and .4 transmissions and maybe others. I understand MB (or ZF?) left out the rear pump sometime in the 90s and some rebuilders leave out the rear pump. It won't explode the first time you put the shift lever in neutral above 30 mph but I wouldn't make a habit of it. IIRC the owner's manual says to not put the car in neutral at speed.

Sixto
87 300D

A freewheeling car either in neutral or an old style overdrive car performs the same. With no back pressure on braking at all from the engine it can suprise you. That is just how much more brakes are required than normal to get stopped. . The really old overdrives where freewheeling when you came off the gas.

I learnt this the hard way in my 50 james dean type mercury. When I had the car serviced they got it into overdrive. Drove away and approached a busy intersection. Came off the gas and was still holding speed.

Fortunatly the car had one of the best braking systems that I ever drove even though not power assisted. It also had so much castor that on a sideways undulating road it tended to track straight. Never had another car that did this over all these years.

Reflecting back it was in some ways the best car driving wise perhaps I ever owned. You just had to take it easy on initial acceleration as the car was so heavy and the transmissions a little too light duty for them. Built like a tank in many other ways .

No other engine ever produced exhaust sounds like a ford or mercury flathead eight with two glasspacks on it. Some of the older guys on site will know what I mean.

Come to think of it I still have a rebuilt flathead and a mercury flathead crank machined with new main and rod bearings out in the garage. I kept telling myself I would find a good body to drop that engine into someday but now the sands of time are runing low.