E63 650i Harsh Gear Changes - Advise

[De@nO]

Hoping someone may have experience with this issue or could point me the right direction..

I have read that the E63 650i gearboxes do suffer from jerky changes... never the less, this is my experience so far...

About 3 weeks back I noticed slightly jerky changes, but not terrible, on my E63 650i auto, under normal driving conditions (ZF 6HP26 Gearbox) 
I put this down to the car needing a gearbox service 

A week ago, driving spiritedly, the car jerked quite violently on the upshift from 4-5 in sport mode (Sport button on and gearbox in DS). - No code... the first time...

I managed to replicate the issue and finally got the gearbox to go into limp mode and throw a code - [font=arial, sans-serif]4F8A[/font][font=arial, sans-serif] (RATIO [/font][font=arial, sans-serif]MONITORING[/font][font=arial, sans-serif].[/font][font=arial, sans-serif]GEAR[/font][font=arial, sans-serif] SHIFT 4-5 [/font][font=arial, sans-serif]GEAR[/font][font=arial, sans-serif])[/font]

My understanding of this specific issue is the engine RPM and gearbox output spline reach an impossible / implausible value, hence the error on the 4 to 5 shift. It seems like pressure isn't maintained correctly on that specific upshift. 

I have had the issue looked at (test drive) by ZF Cape Town and have been advised that it is most probably the clutch pack and ultimately I would be looking at a gearbox rebuild (pending a proper strip, inspection and quotation), which I am willing to do and pay for, but would like to ask if there any other other avenues I can try before jumping into the deep end and if any forum members have had similar issues resolved on a 6HP26 gearbox? 

Would it be worthwhile to try a gearbox service (new pan + filter + oil)  and new seals, or will I just be waisting my time and money, should I just go with ZF and their recommendation?

I have reset adaptions and learnings without any luck.
car has 89 000 km on the clock and don't see any evidence of the gearbox oil having been changed before (From quite a comprehensive & particular service history)

Thanks!

 

[NBN]

Did they do a gearbox oil analysis for you?

 

[Lizzard]

I dont drive the 650i version but the 645ci version, I can tell you from my experience I think you should maybe first try and do the oil pan service first.

Mine started giving me issues on reverse with an error and then it move to first gear, also with errors. I went to ZF here in Boksburg and they did a oil flush and pan replacement for like R4K and the car is driving fine since then. Maybe do the R4K oil pan service first and then if that doesnt solve the problem look at doing the R30K clutches replacement or the R45K drums and clutches replacement. This is huge money, so I went the normal route first, replaced the oil pan. I think replacing the seals with this service the guy quoted me like extra R2K on top of that, so I was looking at R6K for the completed service.

If the seals starts going it will shift harsh based on the pressure that is not maintained, it would be those 4 rubber seals between the megatronics and gearbox. I would go this route first

 

[Rotinaj]

The box is either buggered or not. DO a fluid change and if it worked then yey you saved yourself a bunch of money, if not you are still going to be rebuilding. So do the flush, at 90k it really should not be failing.

 

[De@nO]

Thanks a lot for the feedback, appreciated.
I'll do the pan & oil service and new seals.

Hopefully that sorts it.