Transmission drain hole thread stripped

mug23 · 04-20-2012, 09:33 PM

Hi,

My 944 transmission drain hole threads are stripped. I'm still able to screw in that 17mm plug. I'm not sure 100% if oil will leak or not. What can I do fix this?

Cocacolakidd · Cocacolakidd's Garage

Oops, now that is a problem.

Before changing out the Transaxle try re-threading the drain with a 18mm Tap. Be careful and go slow so as not to cross-thread the tap and old threads. Also all this time you will be cutting metal shards/filings, and some of them may wind up inside the trans-case, be sure to flush all scraps out of the case before returning it to operation.

18mm should do it, but if by chance you do not get full good threads go up one more to 19mm Tap.

Next you will need to find a 18mm plug, and a seal ring to get it all back together again.

Good luck with your Project...

mytrplseven · mytrplseven's Garage

Oh, man, sorry to hear about this. If you drill and tap this the best way I've found to flush out the stuff is pour a gallon of diesel fuel through the tranny. Do it with the drain plug pulled or it'll overflow out the top. Then put a quart of tranny fluid in and drain it. Then put the good stuff in (swepflo (sp) or redline MT-90) As long as you don't turn anything inside while you're doing this, the particles will flush out.

Rasta Monsta · Rasta Monsta's Garage

Um, isn't it tapered (pipe) thread?

Cocacolakidd · Cocacolakidd's Garage

NPT (National Pipe Taper) - no. Machine threads with flanged plug and seal ring/ or gasket.

Rasta Monsta · Rasta Monsta's Garage

Weird, not the case on the 016 box in my 924S.

962porsche · 04-21-2012, 10:20 AM

you would want to rethread it using a time sert kit . bel-metric has them . i just did a customers drain plug on his 735 last week . if you do it right they will not leak at all .

mug23 · 04-21-2012, 12:55 PM

I have decided not to repair that trans as I have another one with an LSD. I'm going to take the short 5th gear out of the stripped trans and put it in the trans that has the LSD and call it good.

962porsche · 04-21-2012, 01:24 PM

Quote:

Originally Posted by mug23

I have decided not to repair that trans as I have another one with an LSD. I'm going to take the short 5th gear out of the stripped trans and put it in the trans that has the LSD and call it good.

dave a time sert would be a PITA to do in the 944 trans but doable . the plug has a very slight taper not the threads in the case .
did you not just pull that trans out of the red 944 your selling ?

962porsche · 04-21-2012, 02:40 PM

dave i was thinking i have a 84 944 at my airbrush shop in hamden the trans is no good but the cases are just fine . if you want the thing it's all yours ! the car is on blocks now and i was just going to scrap the thing . so if you want to take a drive down and pull the trans feel free to do so .

Eric_Oz_S2 · Eric_Oz_S2's Garage

If it was me and you could still reasonably tighten the plug to say 10 ftlb, I would clean the threads up with a tap and just seal the plug with some appropriate sealant/loctite.

How often do you need to drain the trans fluid? If it is not LSD, then maybe every 4 years.

962porsche · 04-22-2012, 06:08 AM

when your using the car for racing your changing the fluid quight often or should be any way !

Rasta Monsta · Rasta Monsta's Garage

No Loctite. I use anti-seize!

962porsche · 04-22-2012, 06:22 PM

i tend to always use just a dab copper anti seize on plugs like that . copper because of heat and anti seize becouse of a metal plug to aluminum case . using a aluminum based anti sieze is kind of point less being the cases are aluminum and as you all know metal tends to freeze it's self to aluminum .