ZF8HP70 Transmission - a cautionary tale!

[Dave Brend]

Hi - thought I’d share my experience of 2 months of pain after cracking my transmission sump cover on a road plate loosing oil and coming to a standstill.

I had an Indy garage do an initial sump cover replacement and refill with Jag OEM oil - which cost about same as liquid gold!!

Transmission then develops an intermittent slipping issue in low gears, typically when pulling away from a junction. Three diagnostics later with “expert” pro register ZF transmission specialists - all said needs a new transmission. One said do a relearn reset - which I did and although it improved the feel, the slip issue was still there.

Went to Jaguar main dealer - end result was 4 litres (allegedly) of top up oil! Touch wood that seems to have completely solved the issue and at c.£500 is a huge relief!

Lessons I learned - 1) don’t trust transmission experts even if they are ZF Pro certified. 2) every so often do a relearn reset as it makes a big difference. 3) if you crack your sump don’t drive as I did until it stopped - hopefully I did no mechanical damage, but I could have done! 4) if you see OEM transmission fluid going cheap - buy it!

Now hopefully that little F-Type drama is over and I can enjoy the car..

 

[Lord Farquad]

How’d you do the relearn reset?

 

[Dave Brend]

Hi

To do the relearn reset switch on ignition not engine. Press down and hold accelerator for 30seconds then turn off ignition. Wait 2 minutes then start engine and go for a drive. Drive as you normally would for 30 minutes, you may feel a difference good or bad for first few miles and it may take up-to 100 miles to fully learn your style.


When I did it I noticed it felt better straight away - but then I was low on oil, as I now realise..

 

[Lord Farquad]

I’ve done this on other cars before, and it was very beneficial, I’ll give it a go in the Jaguar now. Thanks

 

[gasgas]

not sure "Indy garage do an initial sump cover replacement and refill" are the correct people as i think on a gear box refill it needs to be connected up and all the gears need to be run through to clean the plates?

 

[Dave Brend]

Yeah agreed but that’s where I got towed late at night as car wouldn’t run - you live and learn from your mistakes . As you say it’s a pretty complex process to fill the oil and temperatures etc. need to be in range so Jag main dealer service centre is the best option in my view and I reckon would have cost about the same in the end.

 

[Derivative]

Some diagnostic systems (I've an Otofix D1 Auto) will guide you through the refill process telling what to do when, and at the correct temperature. It felt pretty foolproof.

I bought the service kit from these guys...
https://www.ebay.co.uk/itm/175416401900

The only issue I had was the old drain plug wouldn't come loose. The allen key just kept spinning in the plastic socket!
In the end I undid all the sump bolts and just let it all come down together (sump and oil). Bit of a mess, but nothing that can't be cleaned up.

 

[CentaX]

What exactly does this reset? Is it the dynamic adaptation of the gearbox behavior or the clutch (wear) parameters?

It is controversial to reset / delete the clutch adaptation parameters. Even some companies rebuilding the gearboxes will not reset these parameters because these will adapt to your clutch wear status - it could be harmful to reset these without cause. In your case, if you drove with slippage and too little oil, a reset of those parameters might be advisable, but I would not reset it occasionally or without proper cause.

In any case, happy to hear you could avoid a new gearbox. Experts underfilling the gearbox is unbelievable, especially as there is so much documentation and experience with this generic ZF - it's not an exotic.

 

[Dave Brend]

Hi

Yeah I agree, from what I understand this resets the adaption parameters “learned” by the Tranmission Control Module, and not the wear indicators etc.

I’d also read it’s not wise to do this on higher mileage vehicles that may have more wear in the various parts.

 

[Sunscree]

There are tunes out there that keep the transmission parameters as they were when the car was new. I hasn't heard it might be abusive?
One question, what are considered "higher mieage" vehicles.
Ty!

 

[msdmjb44]

'lucky'.

 

[Lunar]

Since you’ve also started a separate post on the subject let’s assume no hijack necessary