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View Full Version : 5HP18 gearbox output seal



whiskychaser
07-20-2008, 03:52 PM
This box doesnt have the big flange nut on the outside. Thats too easy! You need to remove the 7 bolts and remove the tailshaft to do it. But beware. Up to gearbox no 112300 the TIS warns you need to jam something between the parking brake pawl and the housing before you remove it or the clutches drop out! If you have the sump off already its no big deal. You may be advised that the nut inside is 46mm but it isnt. What you will be looking at is this:
http://i290.photobucket.com/albums/ll280/whiskychaser/gearbox%20lift/SP_A0313.jpg

You need to knock back the tabs where the grooved nut has been tapped in with a chisel and mark the flange and nut with tippex so you know the exact position of the nut before you move it. You then push the shaft through the bearing. I was sceptical but it does come out! BMW UK/DE dont stock the socket and if they did it would cost you £70 and take forever to get it. I mentioned this to my neighbour over the garden wall-and a beer. He works for a tube suppliers and within 24 hours I had the tool:
http://i290.photobucket.com/albums/ll280/whiskychaser/gearbox%20lift/tool.jpg

Its made 60mm OD mild steel tubing. But my neighbour had seen a programme about making samurai swords so we had an idea how to harden it. We heated it to cherry red on charcoal in an open fire in his front room and then quenched it in a bucket of water. Did it work? Oh Yes. £70 v 2 bottles of good wine and a lot of fun? No contest! Anyone crazy enough to want to make one pm me as I have all the dims on file:D

632 Regal
07-20-2008, 11:11 PM
so the output shaft actually holds the clutches in position? Thats spooky, if any of them slipped you would need to semi locate them to the center before inserting the output shaft... what if you had the trand on its front and flat, would they move or not?

And why are you into that area anyways I dont see any seal there. ?!?

whiskychaser
07-21-2008, 01:22 PM
so the output shaft actually holds the clutches in position? Thats spooky, if any of them slipped you would need to semi locate them to the center before inserting the output shaft... what if you had the trand on its front and flat, would they move or not?

And why are you into that area anyways I dont see any seal there. ?!?

According to the TIS, yes it does hold them in:
http://www.bmwtechinfo.com/repair/main/741en/index.htm
(Document no. 24 12 016) Which ones it doesnt make clear. If you had the box out and tipped on its end as you suggest then I dont think they would move. But its just easier to jam them in and not take the risk:) Apologies, I should have posted this pic first - it shows where the seal is located. Shame they didnt make the seal in two parts so you could get it past the 3 legs and save a lot of hassle!
http://i290.photobucket.com/albums/ll280/whiskychaser/outputflange.jpg

632 Regal
07-22-2008, 12:30 AM
where is the pawl and what is it blocked with? I rebuilt plenty of trannies but never one of these things. Do you jam it from the side or something?

Just looking for info, might be good for the archives.

whiskychaser
07-22-2008, 03:54 AM
where is the pawl and what is it blocked with? I rebuilt plenty of trannies but never one of these things. Do you jam it from the side or something?

Just looking for info, might be good for the archives.

The pawl is item 1 here:
http://www.realoem.com/bmw/showparts.do?model=HD68&mospid=47405&btnr=24_0712&hg=24&fg=15
There is a small plate protecting the wiring to the solenoids at the back end of the box (held on with a torx 27 screw). If you remove the plate you can see the pawl and parking brake gear clearly. The TIS says use a special tool but I would just jam something between the gear and the casing-the objective is to stop any movement towards the back when you take the case off.

I should say that when you have fitted the seal you tighten the nut up to the exact same position it was in before you moved it - hence the marking. When you come to fit the housing back on, make sure the washer 6 here:
http://www.realoem.com/bmw/showparts.do?model=HD68&mospid=47405&btnr=24_0654&hg=24&fg=15
is sitting on the shoulder of shaft inside the box. These two things detemine end float and you dont want to muck that up