# E64 650i Transmission Slip Only When Cold



## sollyt29 (8 mo ago)

Hi Guys, i just massively serviced my E64 650i 2006 which has just done 60,000 miles (low I know). To keep it brief, I got my local shop to change all major N62 seals which are prone for leaks. Now i have no leaks at all which is great. I bought the car recently from 1 owner from new (a rich family in Dubai who rarely drove the car - hence the low milage for a 2006). The car has been sitting a while which i know isn't good for it, hence why i decided to do the major service and seal changes.

Anyway, to the point - I also decided to change the transmission fluid and filter, which was also handled by my local shop who specialise on BMW's, so they seem to know what they are doing. After i got the car back everything is perfect, EXCEPT that the transmission slips ONLY on cold start 30 seconds after I start to move, followed by a trans warning light (red cog) and drive moderately warning on the iDrive. IF however, i immediately turn the car off and restart, it disappears and never comes on again until the next day or if left for 5/6 or so hours or it's another cold start the next day. I took the car back to my garage that did all the work and he checked the solenoids and said 2 were faulty, so we changed them 2, filled up another 3 litres of extra brand new trans oil (thats what came out when they took off filter and mechatronics unit) but the same problem exists - again, only on cold start. I have been reading here that i should have changed 6 other rubber seals (i wasn't aware of) and annoyed that my garage didn't tell me to and he told me that by replacing the 2 faulty solenoids was a 50/50 chance of fixing it and worst case, he would need to strip down my entire gearbox and replace 20 or so rubber seals throughout, at a cost of £650 + parts. I just wanted some friendly info from anyone here who may have experience the same and if i should go ahead and only replace the set of 6 rubber seals (mechatronic sleeves set etc which is available on eBay as a complete set by ZF) or take his advice and change all the seals 20+ of them. I don't get any other slips at higher speeds and as i stated once the car is warm, i have no issues whatsoever with the gearbox and it drives like new - smooth changes, no jerks or slipping anywhere even when i floor it to redline. I also changed my voltage regulator and IVM recently at the same time so i know its not them. My IBS is faulty which is currently disconnected as new one is on order, however i highly doubt any of these are the issue.

Also ive seen some transmission oil additives that you can buy for around £50 which you add to the new transmission oil, would they work and if so, which one is best?

Apologies for the long post, I hope someone here is able to give me good advice without me having to spend another arm and a leg on the transmission now.

Thank you very much and i look forward to hearing!

Sol.


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