auto transmission 'clutch' slip

[300TDT]

My 200,000 mile W124 1994 3.0 turbo diesel 4 speed auto is giving a very good impression of clutch slip had it been a manual - ie more engine revs, but no, or almost no drive at the wheels. Ease off the throttle and slowly the car moves forward. Once underway it seems OK, until the next roundabout.
I changed the filter and fluid about 12 months ago, and checked the fluid today, all ok, red/no smell/correct level. Any ideas? I'm OK'ish on engines but haven't a clue about auto transmissions.
Any ideas would be appreciated.

 

[television]

Hello and welcome, I only have 2 things that may fit your fault

Transmission slips when driving off in first gear, that is a teflon ring on brake band B2 torn. This is for 722.3 and 5

The other is no power flow, so not your problem as its ok once moving

 

[Number_Cruncher]

If the car sets off better with the lever in "2", then it's a one way clutch which is shorted out by clutch K2 which is the problem. This is unlikely.

If the car behaves the same in "2", then, as a first step, remove and replace the seals for the B2 piston - this is the rearmost servo piston on the gearbox body, and should be accessible in-situ.

You'll need to disconnect or loosen the engine mountings, and disconnect the gearbox mounting and move the gearbox across the transmission tunnel to get enough room.

Take great care not to loose the pushrod which is behind the piston, and to make sure it is in position properly and engages when you rebuild.

Although this piccie is for a 722.435, your gearbox should have a similar layout;

http://www.detali.ru/cat/oem_mb2.as...M=717.433&CT=GA&cat=09S&SID=27&SGR=060&SGN=04

The B2 band is the one towards the right of the piccie, with the snap ring #70, the seal ring #50, the B2 piston, #35, and pushrod, #30.

 

[television]

The car is fitted with the 722.3 box is that the same on that one

 

[Number_Cruncher]

Yes, the layout of 722.3 and 722.4 gearboxes is the same.

The 722.3 gearbox is stronger, and has a higher torque capacity.

While the layout, and operating sequence is the same, the ratios are also different.

722.3

1; 3.68
2; 2.41
3; 1.44
4; 1
R; -5.14

722.4

1; 4.25
2; 2.40
3; 1.48
4; 1
R; -5.14

 

[300TDT]

auto transmission 'clutch' slip - curious twist

Thanks for the advice about poss causes of no drive on my 94 W124 3.0 turbo diesel. After a nightmare drive home yesterday being overtaken by horses and pushbikes - the car seems fine today.
Now I'm in a quandary, I really don't want to go far in case it happens again, but nor do I want to pay for an unnecessary overhaul.
So I wonder - the fact that the car is now driving again - does this mean that the brake band suggested yesterday as a possible cause is OK, or could it be that it slips some times and not others, and will have to be fixed sooner rather than later?
Any advice/ideas would be appreciated.

 

[Number_Cruncher]

That was the point of my post - you can work on the B2 piston *without* doing a full overhaul. The work can be done in-situ.

If you have a decent indpendent automatic gearbox garage nearby, have a chat with them - they'll have probably done quite a few.

 

[television]

The fault that I put up was also for sometimes no drive, do you have a gearbox specialist near you, or would you like to know where one is, though I suspect that you are not in the UK as the TDT never came to the UK

 

[300TDT]

Thanks for both replies. I am in UK. Wye Valley near Chepstow.

As you rightly say the turbo diesel W124 was not sold in RHD - I bought my (LHD) car from Germany 12 years ago, and it's been utterly reliable until yesterday. Quite a shock to have something go wrong with it!

I think finding an auto transmission specialist is probably the way forward so if you know of anyone trustworthy in the Newport/Bristol/Gloucester area that would be helpful. I'm reluctant to just pick one out of the yellow pages - I don't mind paying for a rebuild if it's necessary, but if I can get away with the piston as suggested by number cruncher so much the better.

 

[television]

These people are very good and all belong to this federation, no cheating and all good work, I have recommended many times the link show the map where they all are

http://www.fedauto.co.uk/map.htm

 

[300TDT]

Many thanks for link. I see there is one in Gloucester. Will get on the 'phone on Monday.

Thanks again for your help.

 

[television]

Many thanks for link. I see there is one in Gloucester. Will get on the 'phone on Monday.

Thanks again for your help.

Do tell them of the 2 faults that you have been told about