[ctcarbonari]

I'm looking to order an OE/OEM (or quality aftermarket) drain plug for my transmission oil pan (GA8HP45Z).
I've tried the "usual suspects" (i.e. FCP, ECS, Turner, and various other BMW specialty sites) but for some reason I'm having difficulty identifying the exact part.

www.realoem.com does not identify the part#
https://www.realoem.com/bmw/enUS/sho...diagId=24_1144

www.fcpeuro.com seems to have one but it does not identify my 15' 535i as being compatible.
https://www.fcpeuro.com/products/bmw...0713-1#fitment



I'm hoping to get some feedback from the Guru's out there before I start calling vendors.
It seems really odd that I'm struggling to find a replacement bolt plug but maybe I'm just overthinking it and find myself lost in the weeds.

[Conserve]

It appears that ZF not wanting you to replace plug alone in later model transmission. Perhaps that is either for technical or marketing reasons I do not know. Perhaps you can ask member that is replacing the pan to save you the plug. I am curious why would you want to replace the plug?

[StradaRedlands]

That _looks_ like the right plug to me from memory...

[ctcarbonari]

Originally Posted by Conserve

It appears that ZF not wanting you to replace plug alone in later model transmission. Perhaps that is either for technical or marketing reasons I do not know. Perhaps you can ask member that is replacing the pan to save you the plug. I am curious why would you want to replace the plug?

I want to have a replacement drain plug on hand for future "drain & fill" oil changes (without pan/filter replacement). O-Ring integrity can be compromised over time. Allen heads can strip out. In general, I'd just assume replace both fill & drain plugs every time I'm changing fluid.

Apparently, the plug for the 6HP is different from the 8HP; they both use the same o-ring tho.

It seems odd to me that an OE/OEM plug is not easily available (and very well may be due to ZF marketing/technical reasons). Even more odd to me though that these parts supply vendors do not market a quality aftermarket option like they do with SS Brake Disc Retaining Screws, Aluminum Billet Coolant Hose Flanges, SS EWP Ground Bolt, Aluminum CPs, etc...

[Unspec]

The plug is generally replaced with the entire pan.

[ctcarbonari]

Originally Posted by Unspec

The plug is generally replaced with the entire pan.

Generally, I agree with you.

Suppose a pan/filter has 5k miles of use on it and a person wants to do a "dump & fill" with the transmission oil (as the previous pan/filter replacement would have only removed about 1/2 to 2/3 of the old oil). And, for whatever reason (stripped allen head, dropped plug down the floor drain, or just neurotic PM practice) the guy needs to replace the plug. What does he do then?

OE drain plugs are readily available for the 6HP but not the 8HP.

Am I missing something here?

[NikMN]

Let's say you were flushing your engine instead of transmission. Would you keep "old" oil filter in place? I get what you trying to do. I would replace pan with oil even it costs $$ more

[ctcarbonari]

Originally Posted by NikMN

Let's say you were flushing your engine instead of transmission. Would you keep "old" oil filter in place? I get what you trying to do. I would replace pan with oil even it costs $$ more

Just so others don't get confused, I'll change the word "flushing" to "replacing" and agree that changing pan/filter each time along with the oil would be the optimum method of preventative maintenance.

If the procedure for changing my engine oil only removed 1/2 to 2/3 of the "old" or used fluid and the filter was integral with the oil pan then yes, I would keep the old filter in place during a 2nd or 3rd "dump and fill". (Actually, it would be best to do "dump & fill" just prior to the one when you change the pan/filter as you would minimize the heat cycle time on the bolt).

It's still seems oddto me that a replacement OE allen headed plastic drain plug is readily available for the 6HP transmissions yet seems to be unavailable for the 8HP.

Maybe I'm simply not looking in the right places. Hence, the reason I posted the question. I'll be reaching out to vendors this week and see where that goes.

[tringuyen7757]

I feel like you’re overthinking this whole situation and making the overall topic harder than it is. As long as your transmission shifts smoothly, you’re perfectly fine doing a fluid drain and fill along with the pan/filter change. Thats already the proper way to do the transmission service (~50k miles) according to ZF. If you’re tuned, you would perform the service every 30k-40k miles. Would make sense they don’t sell the drain plug separately since you’ll only be undoing it during the drain and swapping in a new pan with a new pre-installed drain plug. Seriously no reason to drain the fluid every couple thousand miles and filling it back up while reusing the old filter.

[ctcarbonari]

Originally Posted by tringuyen7757

I feel like you’re overthinking this whole situation and making the overall topic harder than it is. As long as your transmission shifts smoothly, you’re perfectly fine doing a fluid drain and fill along with the pan/filter change. Thats already the proper way to do the transmission service (~50k miles) according to ZF. If you’re tuned, you would perform the service every 30k-40k miles. Would make sense they don’t sell the drain plug separately since you’ll only be undoing it during the drain and swapping in a new pan with a new pre-installed drain plug. Seriously no reason to drain the fluid every couple thousand miles and filling it back up while reusing the old filter.

I'll concede that I can overthink the $h!t out of most anything and very well may be doing it with this thread.

I'll also concede that the merits of performing a 2nd (or even a 3rd) "dump & fill" procedure without pan/filter change are based entirely upon subjective conjecture versus the merits of adhering to the ZF process that recommends running a diluted mixture of [~2/3 fresh fluid + ~1/3 old fluid] through another life cycle of the pan/filter.
I suppose only empirical data (i.e. Oil Analysis results from different approaches over the various oil dilutions and their life cycles) would provide any insight of value.

In any regard, this thread seems to have shifted focus onto the "why?" when the question posed in the OP is "where?".

Where can a person purchase an OE/OEM or quality Aftermarket drain plug for the ZF 8HP transmission?

Maybe it can't be done, or at least I haven't found the place to source it yet.

[Unspec]

Originally Posted by ctcarbonari

stripped allen head, dropped plug down the floor drain, or just neurotic PM practice

I would be really, really impressed if you managed to strip the allen head on the plug. It's a torque spec of 8nm - basically hand tight.

If you drop the plug down the floor drain, that's kind of just a "welp fuck". Same way on if you somehow break the butterfly valve on the throttle body - you just need to pony up for the whole part. It's sometimes the unfortunate reality of owning cars sometimes. Also, you can just keep the old plug from the old pan as a spare if this is a concern.

If you're neurotic, you can just replace the o-ring with a similar sized one and it's basically a new plug.

That said, I'm not commenting on if there should or shouldn't be a replacement plug available. My point is just that if there's no replacement individually, you sometimes just need to deal with it. And this part appears to not be made individually, since ZF likely didn't want to bother setting up the distribution pipelines for such an insignificant part for whatever reason.

[ctcarbonari]

Originally Posted by Unspec

I would be really, really impressed if you managed to strip the allen head on the plug. It's a torque spec of 8nm - basically hand tight.

If you drop the plug down the floor drain, that's kind of just a "welp fuck". Same way on if you somehow break the butterfly valve on the throttle body - you just need to pony up for the whole part. It's sometimes the unfortunate reality of owning cars sometimes. Also, you can just keep the old plug from the old pan as a spare if this is a concern.

If you're neurotic, you can just replace the o-ring with a similar sized one and it's basically a new plug.

That said, I'm not commenting on if there should or shouldn't be a replacement plug available. My point is just that if there's no replacement individually, you sometimes just need to deal with it. And this part appears to not be made individually, since ZF likely didn't want to bother setting up the distribution pipelines for such an insignificant part for whatever reason.

Well.....I pretty much agree with everything you've said.
Some of the hypotheticals as to "why" are a bit of a strech, for sure. In any regard, it's a mute point.

Judging by the responses in this thread I suppose the question has been answered. [If I don't ask then I don't know. ]

New OE/OEM or quality aftermarket drain plugs for the 8HP are unavailable for individual purchasing.
(It doesn't mean the search is over tho...lol)

[Unspec]

Originally Posted by ctcarbonari

Well.....I pretty much agree with everything you've said.
Some of the hypotheticals as to "why" are a bit of a strech, for sure. In any regard, it's a mute point.

Judging by the responses in this thread I suppose the question has been answered. [If I don't ask then I don't know. ]

New OE/OEM or quality aftermarket drain plugs for the 8HP are unavailable for individual purchasing.
(It doesn't mean the search is over tho...lol)

I'm sure you can probably find one by Uro, but....it's Uro lmao

[ctcarbonari]

Originally Posted by Unspec

I'm sure you can probably find one by Uro, but....it's Uro lmao

lmao...Exactly...

[DementedF10]

Mine stripped when I did my pan and fluid. So its certainly not impossible. I have done a few fluid dump and fills when I was working new fluid through mine but after those first ones, I would not do it again unless I was replacing the whole pan/filter.

[ctcarbonari]

Originally Posted by DementedF10

Mine stripped when I did my pan and fluid. So its certainly not impossible. I have done a few fluid dump and fills when I was working new fluid through mine but after those first ones, I would not do it again unless I was replacing the whole pan/filter.

Thank you for this post and the feedback from your experience!
Given they're an o-ring seal and such a light torque spec we all know that they shouldn't strip out, but in the real world $h!t happens; especially on plastic parts that get heat cycled.

FWIW,
I was able to find a vendor that sells OE drain plugs for the 8HP. Apparently they're on back order. They cynical side of me says - "Oh, I've heard this one before. Indefinite backorder" but we'll just see how it works out.

If/When an order actually goes thru I'll update this post with Vendor contact info for those out there interested.

[ctcarbonari]

[Solved]

An OEM quality drain plug replacement for the 8HP45Z (RWD) [M18x1.0] can be sourced through Mopar (Dodge/Jeep/RAM/Chrysler)

https://store.mopar.com/oem-parts/mo...lug-68174052ab

[StradaRedlands]

Great sleuthing ctcarbonari!

[ctcarbonari]

Originally Posted by StradaRedlands

Great sleuthing ctcarbonari!

Thanks!
However, all the sleuthing credit goes towards a member of another forum.
He's the one that searched out OEM parts for other car manufacturers that use the ZF 8HP45Z transmission. Damn good idea.

I posted the solution here with the hope that it may help others.

Note: That drain plug is for the ZF 8HP45Z RWD only (not the AWD)