Getrag 260 3rd and 4th issues

[e30davie]

Gday,

Just installed a manual gearox behind an m20b23 in a series 1 e30 coupe.

The whole manual setup came from a 325e. Everytthing bolted up fine.

The gbox shifter mechanism is the later type.

2nd hand everything, except new oem shifter bushes.

1st gear, 2nd gear, 5th gear and reverse gear all appear to work fine. Have driven it up and down the driveway and changed between those gears. stays in the gear, seems to shift fine while moving (synchros working fine).

3rd and 4th have issues.....

I can barely get it into the gear when the engine is on (clutch in). it just feels wrong going into both those gears. i can get it into 3rd and 4th with engine off and then drive, but it falls out of the gear VERY easily and grinds and carries on trying to get it back in again. it also feels like i need to force it into gear, and push it further than it should need to. doesnt slide in nicely like 1st, 2nd, 5th and reverse.

I think i need to rebleed the clutch, because the pickup point is very very close to the bottom of the travel, but it does work fine, car does not roll forward with clutch all the way in. Given it works "fine" in the other gears I reckon that its not the issue with 3rd and 4th.

My gbox has an orange sticker on it so i used automatic transmission fluid.

Guy i bought it off said it drove "fine", but yer.....essentially all the parts are unknown condition to me.

Any suggestions?

Kind of out of ideas.

[djjerme]

Sounds like Syncro's are dying. The one in our race car was dying this weekend, similar issue with just 4th gear. It would go in to gear only about 75% of the time on upshift, and only if you clutched in, let the rev's drop to 4000-4500 shifted, then clutch out. on downshift, you had about a 10% chance of it going in to the 4th. So we had to resort to staying in 5th or carefully downshifting to 3rd after slowing the car enough as not to grenade a rocker arm.

When you missed the gear it would grind and never go in to gear, which is a good indication that the synchro is toast (it provides a ramp for the main gear to engage with the 3rd/4th gear, and so if it's cracked (common) you are pretty much stuck trying to shift like it's not a synchonized tranny (i.e. old school double clutch.)

[TobyB]

The whole manual setup came from a 325e.

which had a dual mass clutch?
I ask because the bellhousing may be deeper, which means (with a single mass flywheel)
you need a longer throwout bearing. Which would mimic a clutch that needs bleeding.

Jeremy's right, though.
Usually 4 is the first to go, especially if the fork gets bent from overzealous shifting
(it's aluminum)

t

[djjerme]

..or using an AKG shifter. :S

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