e39 ZF S5D 320Z transmission problems

[danw23]

I recently bought a 98' 528i with 192k miles, which needed a clutch. I replaced everything with the clutch and got the car back on the road for a few weeks, but then it started to be really hard to shift into gears. Once that happened a few days later it got completely locked out of 1st and reverse. Unless the car is turned off I cannot get it into R or 1st, 2nd also grinds every time. I took the transmission out thinking the problem is the shift pins and detents which I will change.

I am just wondering if the reason why it grinds into 2nd would be because the synchros are going out or would that be because the clutch could not have been fully bled? If I double clutch it going slow it will shift into 2nd no problem, but down shifting from 3rd to 2nd is nearly impossible without grinding the crap out of it. Since I have the tranny out I would like to fix any possible problems.

Any advice or suggestions would be of great help.

[shogun]

Moved to E39 forum from E39 DIY

[Ed CT]

There's a chance the clutch line needs to be fully bled again. Check for leaks along the clutch hydro line and make sure the clutch reservoir is full (it's behind the brake fluid reservoir, in case you're new to E39s).

Some fresh MT fluid will also help. I hear good things about Redline MT, tho I've always used the BMW stuff (Pentosin)

As long as you have the tranny out, you should fix the 5th gear detent. This is a known nuisance where in colder weather the detent sticks, making it hard to distinguish between 3rd and 5th. Do a google search for this. There are fix-kits for sale at various on-line sellers (FCP Euro, Pelican)

[Mike WW]

Sounds like a clutch problem to me, not a transmission problem. The problem is the clutch is not fully releasing. It's most apparent in 1st and reverse because they have the largest rotational/speed difference. Hard to tell with it out, but I bet with it in, you could have started it in 1st, but experienced some creep with your foot off the brake. What did the clutch pedal feel like? All the way at the floor? BMW clutches are noted for being not particularly difficult, but quirky to bleed.

Ed CT's comment about the shift detents are wise too, it doesn't affect all of them, but many. Easy fix I'm told with the tranny out.

[danw23]

Ed CT- yeah since I took the tranny out I am going to do shift pins and both 5th and Reverse detents.
Mike WW- Yeah if I start the car in first with the clutch in it does creep a bit. This is my first BMW so I am not sure how the clutch pedal is normally supposed to feel, but I had a hunch I wasn't able to fully bleed it after I got it back together. Since I have the tranny out I will rebleed the clutch and slave cylinder to make sure all the air is out.

Thanks for the comments. By the sounds of it I won't need to take the whole transmission apart to put in new synchros.

[Mike WW]

There's several techniques to bleeding the clutch, sometimes the subject of much discussion, but one that does not work is pushing on the pedal and opening the bleeder screw.

I've had the best success by removing the slave cylinder, pumping the pushrod of the slave several times, then reinstalling. Not pumping the pedal and emphatically not opening the bleeder screw. Yes it's weird, but that's what works for me.

[danw23]

Thanks. I have heard that the clutch is a pain to bleed. Now that the tranny is out I will bleed the slave cylinder several times just to be sure.
My first BMW so still getting to know all the in and outs. But I did love how it drives.

[pleiades]

Thanks. I have heard that the clutch is a pain to bleed. Now that the tranny is out I will bleed the slave cylinder several times just to be sure.
My first BMW so still getting to know all the in and outs. But I did love how it drives.

Next time you bleed, be sure to fill the brake reservoir high enough so that fluid will flow into the rear partitioned section reserved for the clutch. It's common for folks new to BMWs to fill the reservoir to the max line yet not get enough fluid back into the clutch section.