722.5 Auto box misery

[rayhennig]

Hello All,

My current problem applies to a 1991 300CE-24 with 104 engine and 722.5 5-speed auto box.

Auto box is misbehaving.

1. Starts fine, up changes quite smoothly and at correct speeds.

2. At the 3 to 4 up-change point, it engages 4th for about half a second then changes to 5th.

3. Switching from D to 4th with the lever has no effect, it remains in 5th.

4. Down-changes are very slow and only happen when very low road speed is reached.

5. Manual selection of 3rd results in 3rd being selected after around 2 seconds (very slowly). If

left in 3rd, it behaves musch as it should short of being reluctant to select 2nd except at very

low road speeds.

6. Kick down (foot flat to the floor) results in 2 or 3 seconds of 'thought' and then off we go!

So, basically, everything seems to work but in some cases completely at the wrong time.

My feeling is that this is a vacuum related thing. It's as if the gearbox is entirely unaware of

the position of the accelerator and thus when I am hoping for a down-change.

If anyone can shed any light on this, I should be forever endebted.

My thanks in advance and regards to all.

RayH

 

[simon_wall69]

When was fluid and filters last changed in the box? Also, I think you can adjust the cables as these do stretch over time

I would have thought that vacuum problems would result in a jerky change

 

[type49]

As above. Also, these boxes were very reliable, one thing that was common was 4th gear switch. This resulted in the car missing out 4th gear when going from 3rd, going staight into 5th. This was actually not inside the gearbox but in the gear selector unit. Cheap & easy to fix (although I cant actually remember how to do it)

It's been a loooooooong time you know.........

 

[rayhennig]

Filters & Fluid

Filter & fluid was changed about 18 months ago so we're confident all is in order there.

I never heard of the switch issue before. I would love some details on that.

The point is that the symptoms (downchanges and 4th/5th) all occured at the same time, after the engine mounts, including the rear one at the gearbox, were replaced. Don;t know whether something was disturbed but garage assures me not. This leads me to assume that all these symptoms have a single cause but I may be wrong.

RayH