3.0si manual transmission and diff fluid change: do I HAVE to use new plugs?

[Mainzer05]

I’ve been doing my research to prepare for this job and cannot find anything definitive. I have 2 unopened Redline MTL bottles and 2 unopened Redline diff fluid bottles from a prior car that I want to swap in but would love to not buy the drain plugs if I don’t have to. They’re about $20 per plug right now. What is the consensus on reusing the plugs? I know the ones on the trans have the green seal. Could I avoid any issues with changing the plugs if I just suck the oil out of the fill plug and fill from there so the drain plug was never touched? And for the diff, do the plugs there even have any gaskets that would require new plugs?

For anyone that has reused the plugs, have you had any issues or leaks?

Thanks!

 

[bigwinn]

I’ve always reused the plugs and never had issues

 

[plenty]

You can re-use the plugs, but take care when loosening and tightening as the hex heads are soft and easy to round.

 

[matsmith749]

Do they not utilise crush washers?

I would have thought you could just use new washers & be ok with the actual bolt.

 

[smorris_12]

From memory the plugs just have a machined land to seal against the case. I presume that design choice makes for a "one time fit" to go with the lifetime fill notion, rather than fiddling about with crush washers or O-rings etc, both of which cost money in the initial build.

Saying that, I've always just put the plugs back in and never had a problem; if you're feeling paranoid or the mating faces are in a poor state, an appropriate sized copper washer is pennies.

 

[zedwheels]

I’ve been doing my research to prepare for this job and cannot find anything definitive. I have 2 unopened Redline MTL bottles and 2 unopened Redline diff fluid bottles from a prior car that I want to swap in but would love to not buy the drain plugs if I don’t have to. They’re about $20 per plug right now. What is the consensus on reusing the plugs? I know the ones on the trans have the green seal. Could I avoid any issues with changing the plugs if I just suck the oil out of the fill plug and fill from there so the drain plug was never touched? And for the diff, do the plugs there even have any gaskets that would require new plugs?

For anyone that has reused the plugs, have you had any issues or leaks?

Thanks!

I Changed the oil in the gearbox and Diff last weekend in mine. No problem to reuse the existing drain plugs. Remove the gearbox filler plug first then the drain plug. Reverse then to fill until the oil reaches the drain plug level.
The Diff change your going to need a suction tube to draw out the old oil first because there is no drain plug, once you your Diff has been drained you then need to use the suction pump to take your new oil to refill the Diff again until you see it drip out. Reuse same plug and thats it, job done!

 

[chanlon1]

I changed my gearbox oil two nights ago.
I bought two new plugs from BMW, about £12 each.
Didn’t have to worry about crush washers being reused etc.

 

[smorris_12]

The Diff change your going to need a suction tube to draw out the old oil first because there is no drain plug, once you your Diff has been drained you then need to use the suction pump to take your new oil to refill the Diff again until you see it drip out. Reuse same plug and thats it, job done!

FWIW, they only did away with the drain plug sometime in 2006-07. My April-ish '06 has one.