W210 722.6 transmission slip

[mj2k]

I've got a 300TD S210 estate and an E320 W210 saloon, and they feel incredibly different to drive, even though the transmissions are all-but identical. The 300TD feels old and worn on 173k, whereas the E320 feels like a different car on 155k, with instant take-up and smooth changes.

Part of the problem is the estate's transmission 'slips' on startup, on the way up hills below 40 mph until it's warm, and also slips when accelerating hard before 5th gear lock has engaged, with harsh kickdowns even when warm.

It had been used for towing a horsebox for a couple of years (whilst being neglected) so my initial thoughts are the clutch packs are worn, but are any of the below more likely to be the culprit?

I'm loath to change the transmission fluid 'just in case' because if I need to replace the box or solenoids I'll just be throwing away the money I spent on changing the fluid, and with W210 spare prices how they are, two fluid changes are likely to cost more than a replacement box.

My thoughts are:

1. Clutch packs worn
2. Low / bad transmission fluid
3. Solenoids sticking
4. control module's on it's way out
5. Transmission has 'learnt' to behave badly thanks to the horsebox
6. It's a 300TD estate. They're meant to do that

If it's (6) it'll either be getting a manual conversion or will soon be appearing on Autotrader

 

[bob6600]

You can do (2) yourself, just buy a dipstick and check quality of the oil.

Any idea when the ATF was last changed?

 

[mj2k]

You can do (2) yourself, just buy a dipstick and check quality of the oil.

Any idea when the ATF was last changed?

2012 / 115k at the latest, it hasn't been serviced since

Mmm, just buying the dipstick sounds a sensible idea. I certainly wouldn't be buying the fluid / gaskets just on the offchance though; crazily it's actually cheaper to replace the whole transmission than the fluid!

At Ebay prices you can pick up a complete 722.6 for £80-90 but 7.5l of the correct ATF plus the gaskets & dipstick will set you back £90-100.

 

[BlackC55]

I expect it will be worn inside. Worn clutches and poor seals create lack of pressure. The lack of pressure makes them slip and therefore wear the clutches.

 

[mj2k]

I expect it will be worn inside. Worn clutches and poor seals create lack of pressure. The lack of pressure makes them slip and therefore wear the clutches.

Yeah, that is what I'm expecting TBH, I've owned an old Discovery which had been used for towing horse boxes and the 'box slipped in a similar way. When I checked the fluid it was sludgy and brown, but after the change it went brown again within 5k so I knew it was done for...

I suspect using an auto car to lug around horse boxes probably isn't the best path to transmission longevity, especially if you neglect it into the bargain.

Edit: Heh, just been reading through a few horsey-type discussions about this - the general view is "Get an auto rather than a manual, they don't have clutches to wear out", and only one person thought to post "fit an uprated oil cooler or you'll cook your autobox"