E46 gm auto gearbox

Mytfine

Well-known member
So my e46 auto gear oil cooler gave up the ghost a few weeks ago and made strawberry milkshake with my coolant. I parked the car off while collecting parts as the cheapest quote i got was 10k so DIY it had to be.

I am going to tackle it monday but just have a quick question on the flushing of the gearbox. This is what i plan on doing

1. Drain box and wash out filter with some diesel.
2. Fill box, but leave the output line to the cooler in a bucket, start car and let the pump run while pumping in new fluid to the fill port. Carry on till the fluid is clean.
3. Drain box, replace filter with new one and refill with fresh atf again.

The question is there a manual way to push the old fluid out without running the gbox pump ?

On the coolant side im preparing to flush that at least 3 times i hope i can get it all out.

Thanks

T
 

Nikhil

Honorary ///Member
You better off finding a used gearbox. And doing a Coolant flush. The clutches will start slipping on this
 

Mytfine

Well-known member
You better off finding a used gearbox. And doing a Coolant flush. The clutches will start slipping on this
I dont see how or why damage would have been done, i inspected the gear oil and it has just a little water in it and the car was not driven in that state.

Gbox was perfect before and the little i drove it , its still as smooth as butter.
 

KPM3_30

Moderator
Staff member
I dont see how or why damage would have been done, i inspected the gear oil and it has just a little water in it and the car was not driven in that state.

Gbox was perfect before and the little i drove it , its still as smooth as butter.
As they say, dala what you must..
 

Blue Shirt

Well-known member
I think a proper flush as you describe will be fine.
These auto boxes are not the devil that many people make them out to be. In the family I have one with 330k km, never been opened. The oil was topped up once long ago when a leaky selector shaft seal was replaced.
I also once had an auto box on a 325i Touring refurbished when the torque converter seal blew. It was perfectly fine for many more miles afterwards.
The problem with a used gearbox is that you never know what you are getting. It could be worse than the one that you have. Better the devil you know.
 

Mytfine

Well-known member
I think a proper flush as you describe will be fine.
These auto boxes are not the devil that many people make them out to be. In the family I have one with 330k km, never been opened. The oil was topped up once long ago when a leaky selector shaft seal was replaced.
I also once had an auto box on a 325i Touring refurbished when the torque converter seal blew. It was perfectly fine for many more miles afterwards.
The problem with a used gearbox is that you never know what you are getting. It could be worse than the one that you have. Better the devil you know.


Its on 345k right now but the gbox was still super smooth and responsive, I an 95% sure no damage has been done.

On a used box that is exactly the problem, all that work and no idea if its good or not, besides clutch packs are not that expensive if imported from the states,

People make auto boxes to be like alien technology, they are fairly simple to take apart and put back together if you have any mechanical experience.

The car is worth 40k at best, but it is in such good nick and drives so well otherwise i just would have broken it down sold it in pieces.
 

Mytfine

Well-known member
Done and dusted, gearbox actually got flushed twice as who ever did this previously cut out the bmw connectors and put hose clamps on the cooler lines and one of the clamps failed resulting in one big mess. Thankfully the box is working perfect but i still need to flush the coolant a few more times, i did 3 times but still have oil in the system.

Overall not a difficult job at all, hardest part was the cleanup of the spilled fluid.
 
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