Drain or Leave In

[typ901]

1998 BMW 528iA (150,000 miles). Transmission is a GM 4L-30 I believe. I had the car in to get serviced, as I could not do all of the work myself (Not enough time or tools)...I got into a conversation with the tech advisor and asked him if he would drop the pan, and put in a new filter kit etc...

He told me that the shop does not like to do that especially if it might be the original fluid. My wife bought the car before we were married so I have no idea if it has been changed. How does leaving the old fluid in there make sense? The tech advisor said there was a chance of screwing up the trans and to leave it alone. That does not make sense to me...

Thanks.

 

[Donald]

I would say to have the pan dropped, filter changed and the ATF changed. They can determine how dirty things look with the pan dropped. If they really look dirty then the new ATF will loosen things up and maybe the filter needs to be changed a 2nd time.

Maybe some Auto-RX?

Magnefine inline filter?

You need to to a total fluid exchange. Cooling line flush or multiple drain and refills of the pan.

Leaving the old fluid in makes no sense.

 

[JHZR2]

because the average owner does not want to keep their car very long, and so does not want to open up a new can of worms...

Most owners take poor care of their cars.

If you like it, then do the fluid replacement multiple times, knowing well that you may ultimately face a rebuild... its an AT after all, so rebuilds are commonplace at 160-180k.

Id do a flush first, then drive a bit (100 mi or so), then do a drop pan, replace filter, then repeat after 500 miles, then 1000 mi, then 5000 mi. After that you should be fine.

The key is to clean out the trans, and get junk off the surfaces and clutches. You may never get the AT working again, just realize that... or you may well do so.

Id probably put ARX in the first few times to help everything out... You might want to suck some fluid out and then gradually replace some over time before doing a flush.

JMH

 

[typ901]

Thanks for the advice!

My wife enjoys the car, and I would like to keep it running. Ultimately I would like it to hit the 250,000 mile mark. It runs (shifts) fine, but I try to maintain my vehicles as best as I can afford to. Money for a new car always seems to go somewhere else first.

 

[Donald]

Two things will make the transmission last a long time, assuming its not a flawed design transmission. Synthetic ATF and an inline filter.

I have heard where places do not like to do a flush if the transmission has seen poor service (these are the places that only do a flush, never change the filter), but cannot understand a service adviser not wanting to do a pan drop and filter change.

Bottom line is if the transmission works fine now, it will benefit from new ATF and a filter change.

If it were mine I would drop the pan, replace the filter then immediately do a cooling line flush. Use maybe some decent dino ATF. Install a Magnefine filter. Add Auto-Rx and run it according to the instructions for Auto-Rx. Then do a cooling line flush and run Amsoil ATF if its spec'ed for your car.

You cannot fix any damage that has already taken place by neglect, but you can take the best care of it from now on.

 

[mechtech2]

It is odd for a dealer not to recommend easy service procedures, where they would make money.
I'd make a few calls to other dealers, go to BMW performance forums online, and dig around a bit to see why he may have said this.

 

[typ901]

Service was done at a BMW only Specialist. That is what has me scratching my head, about not replacing the filter and fluid. Eyeballing some BMW forums sounds like a solid idea...I just hear that old phrase 'don't fix it if it ain't broke,' but it cannot be good for the transmission to have maybe a decade old fluid in it...can of worms.

 

[PT1]

My guess is the dealer tech doesn't want to get blamed for a trans failure if the new fluid breaks loose a lot of crud and causes a failure. I would do gradual drain fills over a month or so.

 

[BearZDefect]

FWIW, I finally dropped the pan on my 1997 i30 (JATCO transmission) last month at about 102k miles. The car is 12 years old by the 8/96 build date on the door tag.

There was no sludge in the pan. The two strong magnets were loaded with ferrous fuzz, so cleaning that up justified my labor. I finally wiped the pan as clean as I could with clean white cotton rags and they only got pink from ATF.

Although I have changed the ATF (once single D&F, once cooler line express) since I bought it 3+ years ago, I highly doubt the pan had ever been removed and cleaned. The gasket was stuck in many places, and the endless little bolts had traces of locking mud. I spent a lot of time cleaning the mating surfaces.

How does the current ATF look? Unless it looks BAD, I would drop the pan for a cleaning. You'll also learn more about the overall condition by doing this.