Servicing BMW Transmissions – Changing Fluid is Not Enough

BMW Lifetime Fill?

BMW has been telling vehicle owners for quite some time now that their transmission is “lifetime fill” and does not ever need to be changed.  This is purely marketing hype.  Essentially, lifetime is the lifetime of the transmission.  When it fails, that was its lifetime.

To their credit, the reason they are able to make such claims is due largely in part to the extremely high quality and durability of the fluid used in these newer transmissions.  If you have a newer BMW, you most likely will have a ZF sourced automatic transmission using synthetic Lifegard 5 or 6 fluid.

In my opinion and experience, it is a good idea to do a full transmission service at least every 80,000-100,000 miles.  Transmissions of past eras were more in the range of 30,000-50,000 miles between fluid changes.

BMW Transmission Service San Diego

These automatic transmissions from ZF / BMW are not your run of the mill slushboxes.  They are sealed units, and you will not be able to check the fluid with a dipstick.  They require specialized skill and knowledge to service, and I don’t recommend going to the cheap fluid flush places, you will be asking for trouble.  Even if they get the fluid type correct, they still haven’t replaced the filter.  Even to fill to the correct level is complicated, and has to be done with the engine running and fluid measured to correct temperature.

I rarely ever do a simple drain and fill.  For the ZF 6hp26 series transmissions found on many models, as well as the new ZF 8 speed, the filter is integrated into the pan, so you will have to replace the entire pan.  The fluid is also not cheap, but worth it to insure proper operation and longevity.  In addition, these units are known for oil leaks, so I always replace the motronics connector sleeve as well as the internal valve body main pressure seal.  In fact, I have actually saved several 6 and 7 series BMW owners who thought they needed a whole new transmission by simply servicing these common problem seals.  Although more expensive, doing all these at once every time you service your transmission really is the best bet.  Your transmission will thank you, and so will your wallet.

If you are in need of a trasnmsision fluid/flush service, I can definately get you sorted.  I use OE grade fluid and all original parts from the manufacturer for the filter/pan and seals.   Click here for BMW Repair in San Diego.

If you need a transmission rebuild, I may or may not be able to accomodate you.  As a mobile technician, doing a full rebuild on a BMW transmission is not the easiest thing to do.  However, there are some cases where a transmission might seem like it needs a full rebuild, but can actually be fixed with a partial rebuild.  The 5 speed ZF 5hp24 transmission used on v8 engines of the early 2000’s and late 90’s is a good example.  Often the front drum cracks in half around the snap ring groove. In that case I can order a new updated front clutch drum and repair the transmission without completely disassembling it.  Ends up being a fraction of the price of a full rebuild.

If you have a manual Getrag 6 speed, I do service those as well.  I also do clutch replacement on the manual transmissions.  And if you do have the 6 speed, I can modify the clutch hydraulic circuit to remove the clutch delay valve, which will result in a much more responsive clutch pedal and greater control.

If you have an SMG transmission, I can still service it, but I don’t do a lot of them.  So if it has a major problem and you bring it in to me here in San Diego, after I look at it if I am not 100% on the diagnosis I might send you somewhere else to get a second opinion before replacing anything.  SMG parts and repairs are VERY expensive.  One service I CAN provide for SMG owners is flash programming Euro SMG transmission software into your transmission control module.  This upgrade transforms the SMG.  Significantly improved shift quality and the ability to do launch control at 4k rpm with automatic upshifting at the redline.