MT synchro issues with 2nd gear?

[cdeslandes]

Anyone else experienced the following?

Under hard accelleration, quite often (but not always) the second gear doesn't synch well (i.e. I get the dreaded sound of grinding gears) when upshifting from 1st to 2nd. Just can't shift too fast. All the other gears are fine.

And before someone makes a wisecrack, yes I do know how to drive manual, been doing it since 1973!

[Z4Andy]

When buying a MT car used, one of the tests on the test drive is to rev the car out in 1st and thrust into 2nd.

If it "baulks" or crunches in any way it usually means the synchromesh.

Probably the baulk ring itself as it speeds up or slows down the gear to the same speed of the gearbox shaft so the gear changes smoothly.

If the speed is wrong then it crunches.

Warranty should fit a new gearbox.

[marcw]

Nope no trouble with my MT. Shifts nice and smooth even when driving her hard.

[KINetics]

Originally Posted by cdeslandes

Anyone else experienced the following?

Under hard accelleration, quite often (but not always) the second gear doesn't synch well (i.e. I get the dreaded sound of grinding gears) when upshifting from 1st to 2nd. Just can't shift too fast. All the other gears are fine.

And before someone makes a wisecrack, yes I do know how to drive manual, been doing it since 1973!

Probably the clutch delay valve working against you. Consider a cdv delete.

[2bmws4me]

I sometimes have the same issue and the service advisor told me to warm the car up for 10 minutes before I drive it. Yeah right.

[juhap]

Originally Posted by 2bmws4me

I sometimes have the same issue and the service advisor told me to warm the car up for 10 minutes before I drive it. Yeah right.

You gotta treat her like a woman instead of just sticking it in. The 2nd gear, I mean. Obviously.

[ZheHbKa]

you letting clutch off too early or CDV issue

[cdeslandes]

Originally Posted by ZheHbKa

you letting clutch off too early or CDV issue

Probably a bit of both. I'm fast on the clutch (learned to drive at age 11 on a farm tractor and still drive cars like a tractor!) but I suspect the CDV is making it worse.

[ZheHbKa]

Originally Posted by cdeslandes

Probably a bit of both. I'm fast on the clutch (learned to drive at age 11 on a farm tractor and still drive cars like a tractor!) but I suspect the CDV is making it worse.

check 3 series forum, there are bunch of members that can do CDV delete for $20, its a 5 minute deal, had it done on my E92 335

[HerrK]

It is relatively easy to do a CDV'ectomy. I purchased a spare CDV (about $8) and removed the orifice mechanism, which is merely a screen, ball valve and plastic plug.

1. Pinched off the rubber line leading to the CDV to limit the fluid loss.
2. R&R the CDV with the unorificed CDV.
3. Release the pinch point.
4. Bleed the slave unit.
5. Top off the master cylinder.

Total wheels up to wheels down is about a 90 min DIY if you are competent and feel comfortable messing with the hydraulics.

Normal driving no real difference as you are gradually easing out the clutch anyways. Much quicker clutch lockup during spirited upshifts.

If you are not so mechanically inclined or prefer to have someone else (your local independent shop) do the work, you can buy a modified (orifice less) CDV from Zeckhausen Racing (link below) for about $50 with shipping and replacement CDV included. Probably another $120 shop time for your local independent shop to R&R and bleed the system. FYI - Our E89 Z4's use the same CDV's as the E90 3'ers (PN 21526764872)

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

[cdeslandes]

Sounds like the CDVectomy is the way to go. Thanks guys.

[Z4Andy]

Take the car to the dealer first before trying any mods.

The car is under warranty so let them rule out any gearbox issues.