Hey all...

While I was under my car yesterday replacing my tie-rods - I noticed that I had some leakage near my transmission.

At first I thought it was leaking from the transmission drain plug, but later noticed it's coming from above near the back.

I'm not sure what it's coming out from - but it looks like some sort of seal. I looked in my Bentley manual and couldn't tell by the pics what part/seal it is.

My question is:

How much does a repair like this cost?

I'm pretty sure it's either the selector shaft or the output shaft seal.

Thanks...

anyone know this?

If it were the output shaft seal, most of the tranny would be dry and the fluid would start at the rear of the tranny. Input shaft seal would show fluid comming out of two holes in the bottom center of the tranny and spraying back from there, over and past the drain plug, etc.. Engine rear main seal would show oil comming out of two larger holes in the bottom center and one about one inch away, toward the drivers side; These will be rectangular gaps between the motor and the tranny, and will show fluid spraying back from there. Selector shaft seals don't tend to leak much at all, unless you have the tranny out and tip it on it's side.

I'd get under there and get the best brake parts cleaner I could find. clean everything off as best you can and then get the car warmed up. Drive it pretty hard and then take it home and lift it up again. check for fresh fluid, and most importanly, the color of it. You'd be surprised how far back fluid can spray and collect dirt. Check for holes in your breather hoses, especially the one that connects to the dipstick carrier. check power steering lines as well, as the clamps tend to not hold well over time and will create a big mess.

i'm pretty sure i have a similar issue. i have a slow leak coming from the rear of the tranny up near the guibo. i leaned it well last weekend and it was back yesterday. i havent noticed any drips, just wetness.

what are the steps i should take to figure it out? do i need to drop the driveshaft to get to that area? any common problem areas back there? how much of a headache am i in for?

any advice?

i was talking to a guy i know who knows a guy who's name i wont mention said that for the shift linkage input seal, instead of pulling the old one you, you can simply tap a new one in on top of the old one.. any thoughts on that?

If the selector shaft seal is leaking, there's no way to tell if the output seal is leaking too. Replace them both. You pretty much have to remove the output flange to reach the selector seal anyway.

Some transmissions use an o-ring to seal the flange to the shaft -- replace it if it's there. Replace the ouput flange nut lockplate if used, and use blue loctite on the threads.

Take the occasion to disassemble and lube the shift linkage. Use new clips. If it's a high-mileage car with a loose shifter, just replace the linkage and rubber mounts.

I know of some hack mechanics who don't remove the old seal. A job like this will take all day for an amateur -- surely you can spare two minutes to remove the old seal.

yeh. when i do it i plan to replace every bushing in the shift linkage and maybe add the UUC DSSR. i guess a new flex disc too. shes at 112k miles. if i have to drop the drive shaft them maybe look at that drive shaft bear too? hrmm funny how this stuff multiplies :P

so if you say i basically need to take off the output flange to get to the selector seal, then ok ill do it all.

how do you get the selector seal out? from what he said it sounded like a pain in the ass to get out.. no?

thanks a lot

Use a small pick. I've done it twice.

When I did mine, I dropped exhaust and driveshaft. Not too bad if you've done it once already.

hrmm. ok then i have this list of parts so far:

output shaft seal: $23.50
selector shaft seal: $3-6.50 (depends on brand)
guibo: $71
DS center bearing : $72

is there anything else i can/should replace while i'm in the area? any special tools? do i really need teh special 30mm deep socket? oh and i need new bolts for the DS flange and nut plate? hrmm dont see that on pelicanparts.

All the bushings.

For DS flange nut, you can get them from dealer for pretty cheap.

Also, I have an extra brand new shifter coupler and foam bushing, item 1 & 2on the pelicanparts diagram. If you need that, I'll sell it to you for cheap.

Not all transmissions use a lockplate. I wouldn't replace the bolts or center support, but it can't hurt. The guibo is a good idea. I would also replace the transmission mounts. They may look ok, but when you compare old to new you'll see a difference in height of 15-20 mm.

The rear of the output shaft extends past the flange to act as a centering pin for the driveshaft. You'll need a socket long enough to fit over it.

I use a long thin screwdriver to remove the selector shaft seal. Slide the shaft all the way in first, and afterward pull it back and check for scratches. It should be ok, but can be cleaned up with fine emery cloth.

You won't need to remove the exhaust system, but if you want to anyway, replace the flange gaskets. Before lowering the rear of the transmission, remove the radiator fan and intake air boot, and loosen the engine mounts.

the output shaft seal on my old 325is was leaking too - you'll need to fab up a tool to keep the flange from rotating as you remove it