trouble downshifting to 1st or 2nd while in motion

[bimmern00b]

as subject says, i'm having difficulty shifting to first and second when the car is in motion, even as slow as 5 mph. if i'm stopped, i can shift into any gear without any problems.

any speed and i can't downshift to 1st or 2nd. i can go from 1 to 2, but not 3 to 2 or 2 to 1. if i try to shift to 1st, it just stops like its being blocked. if i'm downshifting to 2nd, i hear some grinding...

what could possibly cause this? will this be expensive? my first e30, and its only been a week....

thanks in advance

[Danny]

Synchros.

They are shot.

[euroshark]

1st really isn't a gear that you want to shift into while the car is moving unless you are literally just rolling that last few feet up to a stop sign. The reason it's difficult is because everything in the transmission is in motion and you are forcing the syncro to grab the gear and stop it's rotation. It's easier for the syncros to stop the other gears because of the ratios but 1st a big gear and is therefore not as easy to stop... I hope this all makes sense, it's beer-thirty over here.

If you hear grinding you probably already have weakened syncros either due to age or abuse. If you are going to be shifting from 3rd to 2nd you should try to "rev match". As you push in the clutch to go from 3rd to 2nd, give the throttle a little poke with your right foot to bring up the revs to approximately where they should be in 2nd gear with the clutch out. In essence you will be matching the engine and gear / road speed and making it so that the syncros don't have to work as hard to get the gear spinning the correct speed and everything will engage easily.

Are you sure your clutch is disengaging completely? Does it feel like the clutch "grabs" really close to the floor? If it's only partially engaging this can exacerbate other issues or maybe even be the whole problem.

You may also have sticky and worn out shift linkage which will make it a bit harder to engage the lower gears, so it's not a bad idea to clean everything up and freshen the linkage up with new bushings and grease. Like I said though, try rev matching and don't go from 2nd to 1st unless you are stopped or BARELY moving, especially since you are hearing grinding.

[bimmern00b]

makes a lot of sense. thanks for taking the time to provide the info.

rev matching didn't even work at first. i got frustrated and pulled up on the shifter (as in vertically) and all of a sudden i can shift into second.

not well, but rev matching works, but its not much of a tolerance. took it for a drive today and i'd say i have to be within 500 rpms of where it should be in second for it to allow me to downshift to second. otherwise still stops me cold.

its never really in issue except when i'm rolling to a stop but then i have to go suddenly. i had this issue yesterday and i should shift into second so i couldn't go.

thanks again for the quick info.

[nando]

1st will always be hard to get into gear while moving, but 2nd should be pretty easy. your 2nd gear synchros are probably bad either way, how many miles are on your transmission? Mine has 250,000 and it's balky at times but 2nd gear will slip right in at nearly any speed.

could it also be worn linkage? you said it worked after you tugged on the lever. when's the last time you rebuilt the linkage? if it's original it's definitely time.

[bimmern00b]

230k

yea, couldn't shift in 1st or 2nd today going maybe 2mph.

all parts are original. probably should replace anyway as there is so much play in the shifter.

time to overhaul the trans and shifter

[euroshark]

Start with the shifter before you go through the trouble of pulling the transmission!

In the event that you need a transmission rebuild on these cars, it's usually going to be cheaper to find a good used one.

[nando]

yeah, 230k on the original linkage - I'm not surprised you're having trouble getting into certain gears.