Engine Rev/Gear Engagement

[supertack]

This is weird.

Upon up shifts to 2nd & 3rd, the gears don't engage immediately. I hear a slight rev of the engine for a fraction of a second before the gear fully engages, & the power is diverted to the wheels. This only seems to happen at higher rpm's.

Before, as soon as an up shift was made (say 2nd to 3rd), I'd get an immediate response to the shift in the wheels from a nice hard shift. Now it almost seems like the gear is engaging slower, & having a hard time catching up to the engine speed.

I don't understand what's wrong. The shifter still engages smoothly. I don't think the clutch is bad, & the problem doesn't appear at lower rpm's during regular driving. It only seems to happen at higher rpm's.

Logistics: '97 328is, 5 speed

Thoughts??

[parolof]

to test if the clucth is slipping/going bad, drive the car at 30-35mph in forth gear and the accelerate hard, the revs should not increase

[supertack]

And they did not. I don't think this is a clutch related problem. I put some added pressure on it yesterday, & the issue is really prevalent shifting from 3rd to 4th. It's as though the transmission can't decide whether to stay in 3rd or move to 4th. This lapse takes place in under a second, but none the less, something is wrong. It almost sounds like an automatic transmission having trouble changing gears, but this being a 5 speed, & the shifter being fully engaged, I'm having a hard time trying to figure out what it could be. Any thoughts would be appreciated.

[parolof]

what about the CDV then?

[supertack]

What's that?

[parolof]

http://www.zeckhausen.com/CDV.htm

[supertack]

Wow, that's something I didn't even know existed. Have you done that mod Parolof? I live in Chicago, but if I was in Jersey I'd definitely pop the $150 to have that modified valve installed.

So getting back to my problem, it sounds like my oem clutch delay valve is bad. That would explain why the trans is hesitating before it shifts from 3rd to 4th. However, could it have anything to do with the master or slave cylinder?

[parolof]

no I don't have one one my 318is, don't know why. Think it's just for the US market. I know that people just remove them.

[Geno325is]

How does a CDV go bad? its only a metal fitting- Youre positive its not your clutch showing its age/wear? I cant relate since my '93 325 didnt come with CDV (obd2 96-99 i believe)

But good 'mod' i guess, jack that car up and take it out.

[supertack]

That's a pretty good point Geno, after I started thinking about it, I don't see how it can go bad. Now since I've only started to notice this problem, maybe it is the clutch.

[Geno325is]

Still a good mod tho- I know id do it for the faster clutch engagement and feel.

[Jeron]

I removed mine (CDV). I have my notes from the removal somewhere if you want them.

I didnt think your problem sounded like the CDV when I read your first post but it is a great mod so i would do it anyway IIWY.

[supertack]

That would be excellent Jeron. I found a write up at this site (link below); however, it is on an e46. I dunno how much different an e36 is gonna be, but I'd like to be comparing apples to apples when I do this.

http://www.bmw325i.net/cdv_removal.shtml

It looks pretty simple, but I have to wonder about how difficult those nuts are gonna be to loosen after 8 years of exposure to Chicago winters. How difficult was the proceedure?

[Jeron]

Here is a good write up or you can just navigate to it at uucmotorwerks.com:
http://www.uucmotorwerks.com/html_techtip/techtips/check_valve.htm

Here are my notes:
The check valve on my 97 M3 was on the last bracket before the clutch slave cylinder.

You will need 11mm, 14mm and 17mm open end wrenches. Also a drain pan, a hose clamp or hose clamp substitute and possibly clutch bleeding equipment.

First, use the 14 and 17 to loosen the rubber hose from the CDV, don’t actually try to unscrew it just break it loose. Put the hose clamp on the rubber hose. Take the 11mm and remove the hard line nut on the slave side of the bracket. This nut actually is threaded onto the CDV which sticks through the bracket and acts as a stay. Once the nut is off the CDV will separate from the hard line and you can use the 14 and 17mm to finish removing the CDV from the rubber hose. Then stick the male fitting of the rubber hose through the bracket and attach the hard line going to the slave with the 11mm nut. Work quickly to reduce the chance of needing to bleed the clutch.

It’s a little messy because fluid will be leaking from the slave on the hard line side. Hopefully, afterward you will not have to bleed the clutch but be prepared just in case. Bleeding the clutch may require the removal of the slave and hand actuation of the slave piston.

[supertack]

Originally posted by Jeron
Work quickly to reduce the chance of needing to bleed the clutch.
Hopefully, afterward you will not have to bleed the clutch but be prepared just in case. Bleeding the clutch may require the removal of the slave and hand actuation of the slave piston. [/B]

How will I know if bleeding the clutch is necessary? Do I need to add more trans fluid after removal of the CDV? Is it possible to screw this up? What kind of damage can I do?

[Jeron]

The clutch will go to the floor or not have the correct feel. I did mine without bleeding the clutch. Try not to let fluid drain out of the slave.

The Tranny and tran fluid are not effected in any way.

No way to permanently damage anything unless you strip threads, cut hoses or something catastrophic. All you are doing is removing a threaded fitting that sits between a hard line and soft hose.

The worst thing that could happen is air gets into the slave and since the bleed screw in on the bottom of the slave you may have to remove the slave and turn it over to get the air out If you work quickly and take time to think through the steps before you start pulling things apart it should not be a problem.