[Shinel]

So my reverse gear is shot on the s6-45bz, but I'm gonna replace the synchro. Took all apart, but wondered if anyone knows how to remove these shift/detent pins?

[DCook]

Following this. Also curious where you're getting the syncros from? Id like to rebuild my n54 6mt syncros.

[TheMidnightNarwhal]

Originally Posted by DCook

Following this. Also curious where you're getting the syncros from? Id like to rebuild my n54 6mt syncros.

Yeah I thought these transmission couldn't be rebuilt and they didn't sell parts.

[bbnks2]

Originally Posted by TheMidnightNarwhal

Yeah I thought these transmission couldn't be rebuilt and they didn't sell parts.

Anything can be rebuilt. This issue is that the syncrhos aren't available and there are no rebuild kits. so you need to fabricate up your own way to plug the transmission back up with press fittings. maybe by tapping all the holes and plugging them.

I believe a reverse synchro has been cut that will fit the 45bz and is being sold by the aftermarket. Most people need 2nd gear.

[Shinel]

I have a 2nd donor gearbox, so oem synchros. Disassembly is somewhat straight forward but you have to take a few detent pins out to not break anything.

[kjburns25]

Was the transmission that you pulled apart in this post an xDrive transmission, by chance? My trans shop is stuck at removing the gearset from the rear housing (to replace the reverse synchro). I was wondering if perhaps you had any advice?

[Welcome to NBA Jam]

It's like a work of art.

[northbranchroad]

Any update on this? I've been driving my car without a reverse gear for about 6 months and would love to get it fixed if possible.

[Shinel]

Well, basically I had to take apart two transmissions, and put one together from both. It's a PITA, primarily on reassembly. There are some parts that you need, that if you don't carefully remove from the good one, you're pretty much shit out of luck.

[northbranchroad]

I'll probably just sell my car since I don't have a donor trans (let alone 2), and in the meantime I'll just keep picking my parking spots very carefully. Glad you got yours working!

[hoda022290]

Originally Posted by Shinel

Well, basically I had to take apart two transmissions, and put one together from both. It's a PITA, primarily on reassembly. There are some parts that you need, that if you don't carefully remove from the good one, you're pretty much shit out of luck.

There are two companies in the UK that sell the reverse synchro alone or a kit with a few plugs and seals for ~300. My question to the OP, could you make a brief guide to how to get to the rear synchro? There is zero info online minus a polish guy tearing one apart (video in polish). I mean like super high level.
ex.

1. Remove sensors, shift linkage
2. Remove detents by......
3. Removing housing bolts
4. Use gear puller
5. Tie up gear assembly and remove as one unit

I don't know if those are the actual instructions in that order. Just an example. If I can find some info on the teardown, I'm willing to make a detailed DIY with links to the parts.

[Tomla]

Originally Posted by hoda022290

There are two companies in the UK that sell the reverse synchro alone or a kit with a few plugs and seals for ~300. My question to the OP, could you make a brief guide to how to get to the rear synchro? There is zero info online minus a polish guy tearing one apart (video in polish). I mean like super high level.
ex.

1. Remove sensors, shift linkage
2. Remove detents by......
3. Removing housing bolts
4. Use gear puller
5. Tie up gear assembly and remove as one unit

I don't know if those are the actual instructions in that order. Just an example. If I can find some info on the teardown, I'm willing to make a detailed DIY with links to the parts.

I have a 2011 335i Xdrive with a 6 speed manual transmission. It is pretty much impossible to get it into reverse. It doesn't matter if the car is running or not. I have conclude that something in the transmission is damaged. Looking around it seems that this is a fairly common issue. Does anyone know what fails? Any aftermarket rebuild parts available? Used transmissions are hard to get for this.

[xquatch]

You had me at 6MT teardown. Yeah, no rebuild kits for sale, but you can buy a remanufactured 45BZ form OEM resellers, so the parts exist. Maybe they should just sell an adapter kit for the 53BZ since it seems to be more durable. However, I do see them going down sometimes as well. I'm swapping out my 70k miles 45BZ that has the second gear syncro issue, with a used 45BZ I found locally out of a newer car. If it's bunk then I'll either buy the reman or maybe do the 53BZ retro. Honestly, the gearing ratio for 2nd gear isn't quite right.