Hard Shifting after work on car

[Dervman]

I recently finished some work on my SDL and now the Tranny is shifting with hard shifts instead of the smooth changes previously.

Here's what I did, and yes I know some of these cannot be related to the Tranny:
- Replaced Vacuum Pump (Original flat face was working fine - I think)
- Fixed Exhaust Leak at front/rear manifold joint.
- Drained & Flushed Cooling System & replaced top & bottom hoses.
- Replaced Alternator Brushes/Regulator.
- Removed EGR Valve (previously disabled) and associated vacuum hoses.
- Cleaned out crossover pipe and installed new gaskets & seals.
- Replaced all filters (air, fuel & oil) and oil.

Anybody have any ideas??

[Jim H]

Look for the loose/leaking vacuum line or fitting, probably bumped, loosened or broken as you worked on the engine.

Follow the vacuum line from the brake booster source line ahead of the check valve, to the proportioning valve on the injection pump, back to the blue vacuum amplifier on the driver's side fender, through the switchover valve and finally down to the transmission vacuum modulator.

Low/no vacuum = higher shift pressure = harder shifts.

Best Regards,
Jim

[Dervman]

Thanks Jim, I'll check out the vacuum system.
I did move a bunch of stuff around when I was removing the vacuum lines to the EGR valve solenoids.

It looks like on my SDL the small line from the vacuum pump goes to a 4-way connector and then there is a line to the proportioning valve on the injection pump, then over to the blue amplifier then the changeover switch (square top unit on bulkhead?) and then I guess to the transmission vacuum modulator. Where is the vacuum modulator located ?

[Jim H]

Modulator is at the end of the vacuum line!

It's on the side of transmission. You probably didn't disturb it, since you weren't under the car.

Best Regards,
Jim

[Dervman]

I checked all the lines and they seemed OK except for one that broke when I flexed it - now replaced. I think the problem may be the 4-way connector above the vacuum pump. I moved the vac lines that go in/out of this connector and the shifting seems better although not quite as smooth as I remember.

Now I find I have no heat to the footwells in the car
I have to believe these things are related as it was working fine before the work I did. I'm not quite sure where to start. Defrost and side vents work OK but Centre vents seem dead also. Could low vacuum be affecting the ACC ?

I'm leaving for Florida tomorrow (driving down) and running out of time. The good wife will not appreciate cold tootsies if I can't fix it.

HELP !!!

[Rick Miley]

Yes, the doors that direct airflow are vacuum actuated. So concentrate on tracking down all the vacuum leaks.

[Rick Miley]

Unless you're at least 100 miles from the nearest auto parts store, you'll waste a lot more time hunting down bad connections than going to buy a MityVac NOW. My plastic model was $26 in a "Brake Bleeding Kit" at AutoZone. Every Mercedes should come with a MityVac in the glove box - there's no excuse not to have one.

[Dervman]

I agree I really need one.
Problem is every parts supplier I've contacted locally here in the frozen north wants $100+ for the privilege of me owning one
$30 sounds a whole lot better to me.

[Rick Miley]

CarQuest has the metal version for CDN$64.95 here. It's in the lower left corner of page 21.

[Dervman]

That really makes me
I called CarQuest today and they told me that the MityVac was coming ON SALE next week for $124 Cdn. I asked if they had anything less expensive and was told no. Grrrrrrr
Thanks for the lead.

[Dervman]

I found the problem. It wasn't a leak but a blockage in the flex hose from the vacuum pump to the first piece of nylon vac hose.
All is now well and Mamma's feet won't freeze on the trip south.
Many thanks to all who pointed me in the right direction - this is a GREAT site!!