rockatansky

Hi, I bought the car two months ago. After repairing a gearshift failure, now I was doing some maintenance works on the car for liquids, filters, etc...

Yesterday I tried to change the trans oil and I ruined the upper screw in the transmission cage. I read in the wsm that this screw should be tighten with 20NM of force and I thought it will loose easily. Nothing more far from reality.



I used this tool (in straight position), with the head from 928motorsports:




I did some tries without success, and the last one with all my force. too much for the depth of the allen hole. The tool jump out of place and I left the hole as you see in the picture.

In a first thought, my options are:

- buy a new transmission :((((
- leave it as it is (should be oil in there I think), finish the other tasks and start the car and drive it without new oil for the transmission never again...
- find an alternative way to fix the problem (right now the tool doesn't hold there for turning the screw).

other facts you should know:
-2 months ago I don't even know how to change oil on a car (is obvious that I haven't learned yet)

-wet you can see in the hole is wd40 penetraiting oil, not transmission oil. The screw hasn't moved an inch.

-car is europe MY 1980 928 (not 928s), transmission has no LSD

-bought car two months ago with a socket ball (gearshift) failure that is already solved.

-I know that the car has been stopped for two years from the previous owner. Car came home on a truck.

-I need to do some other tasks, and mount exhaust, etc, before trying to start it for the first time.

-Tonight I have had nightmares with this (literally).

-any thoughts will be very appreciated.

Darklands

Three possibilities.
a) let a professional mechanic do the job.
b) use a torxx tool in the right dimension and push it with a hammer in the hole of the screw.Maybe you can wrench the screw out of the transmission.
c) use an chissel and push the screw with light slashs with a hammer around till loose.

I think it´s not as bad as you think.

Than buy a new screw and go on.

Little pushs with a hammer on the allen tool in the screw can loose the screw.

rockatansky

Sterling, I thought that the transmission cage were one piece. And you say that you could remove the rear plate only where the screws are?. Could this be done without removing the whole transmission from the car?. That will be great.

Could you point me to a part number for the rear plate or a page that sells it?. I checked on 928intl but only see whole transmissions.

If I could remove only this plate, and try to remove the bolt out there. Will be great. But the great part is that if I break it up completelly I will be able to only replace only this back cover. Am I right?.

darkland:, thanks I will study your advice. First I will try to get a confirmation about removing only the rear cover and then I will try to work on this screw.

Daniel Dudley

If you drill the plug, and then split it with a metal blade in a jig saw, it will come right out. Use a non hardening sealant on the threads when reassembling, something like Blue Hylomar.

Tight is highly overrated.

Daniel Dudley

Oh yeah. Some guys would weld a nut to that with a mig. You weld through the inside of the nut.

Mrmerlin

first you need to clean out the plug make it spotless,
then put some wet rags around the top of the trans,
then use a torch to heat the plug surround ,
then quench with PB blaster,
do this heat and quench a few times,

then put some valve grinding compound on the tool and smear some on the plug flanks,
insert tool and loosen the plug

Dave928S

As Sterling said, you can remove the rear cover and then work on the stuck plug.

However ... when I first got my car the fill plug on mine wouldn't move either, no matter how much force I applied ... until I tried a rattle gun and it came out first go easily. If you can jam something into the plug and drive it with a rattle gun it's worth a go, before you take the back cover off. Same with the axle nuts ... used a 4 foot bar and bent it... got them off with the rattle gun.

rockatansky

Thanks to all of you. I'm writing down all your advices to study all carefully and see which is the best way to proceed.

The really good news for me is that there are solutions to get this sucker out. As Dave says, probably I will try first without removing the cover (which I have found it costs about 300$, not too much for what I was thinking). If I cant, I will remove the cover, and if I ruin the cover, I will buy a new one with new screws on it.

rockatansky

Dave, could you point me to a web page with the rattle gun you own?. Just to see the quality of the tool I must be searching and see if it is available around here... thanks.

Dave928S

As MrMerlin said ... before you try anything get that plug spotlessly clean, or you won't have a chance of anything holding on what's left of the flats.

Dave928S

I'm not on my home computer now or I could post a photo for you. I've got a 3/4 inch drive automotive gun, just like the type you'd see at a tyre dealer for wheel nut removal. I went for a 3/4 inch drive gun instead of 1/2 inch drive because of its higher torque ability, you should be able to find something similar at your local auto tools outlet. They're handy to have for all sorts of stubborn fastener removal ... with care.

Jerry Feather

Hi Rocky. (Can I call you "Rocky?") My first thought is that I am very pleased to see another young driver take on a 928 like you are having essentially not automotive experieice and jumping into the middle of some serious service and repair work. Good for you.

My second thought is that all of these guys have given you some really great ideas about how to solve the problem with the trans service and with the plug removal.

Third, I really like the suggestion by Mrmerlin because that is very much like the way I did essentially this same task a long time ago with my first Porsche, a 356C. Based on what I did then with a torch, a drill, a big easyout, and a bowl of ice cubes and what he suggests now, I would suggest something similar as follows:

One thing no one has suggested is the use of a TORX bit/tool in place of the hex that you have now rounded the recess out with. Therefore, I would suggest that you use a propane or mapp gas torch or just a heat gun to heat the area around the plug as hot as you can get it, then use the idea of squirting the PB blaster into the center of the plug to cool it suddenly, then drive the TORX tool into the plug and try to remove the plug with the correct size of breaker bar--half inch drive should be enough.

If that doesn't work then I suggest that you drill the center out of the plug, at least very deep, but not through, with as large a bit as you can deal with in this situation, as big as the hex drive or even slightly larger. Then possibly using the same TORX tool driven much deeper in, or using one of the later style of easy-outs that you find at Sears (or wherever you can in Spain), follow the same routine with the heat and the PB blaster, or other instant cooling method for the plug, and the breaker bar and see if the plug will come out.

I'm sure we will all be happy to know how you actually did it after you get the plug out.

Jerry Feather

jcorenman

You car is 1980, correct? The rear cover would be 928 301 035 04, which 928 International has listed (used) for $100, here:
http://www.mailordercentral.com/928intl/prodinfo.asp?number=U928%20301%20035%2004

You would also need a new gasket, 928 301 395 03, and new screw-plugs of course, 999 064 019 02 - those are not expensive.

And of course, be careful not to install the new plugs too tight-- they are a tapered thread.

Steen Jensen

Am I imagining things or are those fatigue cracks or stress risers on the left hand side.
If so , I'd be very careful with this situation...

Landseer

Just replace it.