Transmission drain and fill?

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RyanRR

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Searching through the forum I've found plenty of threads about the nice metal pan conversions w/separate filters (found at Atlantic British, etc) that make swapping pans much easier, but I'm curious about the feasibility/practicality/sanity of simply draining my existing fluid and refilling the amount that was drained?

Assuming I'm using the same ZF Lifeguard fluids they used in the factory, would this be a suitable alternative to replacing the full pan/filter for the time being?

Reason I ask is because I just bought the vehicle and like I always do, I've changed all fluids in the vehicle so far (engine, differentials, transfer case, etc). So far all of the fluids looked good (much better than my RRS that got those fluids changed for the first time @ 120k), leading me to believe the previous owners actually did care for the car (plenty of service records, but these jobs were not indicated). The transmission pan looks very clean as well, so it's likely been done in the past if I had to guess.

So rather than spend the $320 in parts for the pan + fluids, I could save some money and quite a bit of time by just swapping fluids..

No shifting issues whatsoever, I just like to do these things for peace of mind.

-Ryan
 

ryanjl

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This is still on my "need to do" list--and I've been sitting on the parts at home for some time--but my thoughts are that you get a lot more of the fluid out by dropping the pan than you do by merely draining, and even then you still need to drain and refill a few times in order to make sure you're fairly close to being 80 to 90% new fluid.

You also (obviously) get a new filter by swapping the pan.

On the other hand, it certainly wouldn't hurt to just do a drain and refill.

Keep in mind, though, the fluid itself is a big component of the cost.
 

RyanRR

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This is still on my "need to do" list--and I've been sitting on the parts at home for some time--but my thoughts are that you get a lot more of the fluid out by dropping the pan than you do by merely draining, and even then you still need to drain and refill a few times in order to make sure you're fairly close to being 80 to 90% new fluid.

You also (obviously) get a new filter by swapping the pan.

On the other hand, it certainly wouldn't hurt to just do a drain and refill.

Keep in mind, though, the fluid itself is a big component of the cost.

That's kind of my dilemma, I want to save the labor time and a little money, and I figure it can't "hurt" to swap 6 of the 7 liters of with fluids and leave the old filter, etc..

Plan would be to swap the whole pan next year to push off some of the current maintenance and costs I'm incurring right now.

My next project is swapping brakes on all 4 corners, parts showing up tomorrow.
 
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mm3846

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I planned on doing just a drain and refill, then I couldn't get the dumb plastic drain out of the plastic pan. It was frozen in there.

Ended up doing to pan swap anyway. But otherwise everything you said sounds good. my filter was totally clear with 57k miles on it.
 

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