Manual Gearbox Recondition

[Vez010]

Hi,

I’ve recently purchased a manual gearbox in readiness for an auto to manual conversion however I’m wondering whether it’s worth having it reconditioned before I put it in.

I believe the box has about 120k miles on it but there’s no way for me to verify that. Whilst it’s not particularly cheap to have it reconditioned I do intend to keep the car for the long term so am leaning towards having it done.

Would be useful to get some of your thoughts/suggestions/recommendations on the matter.

Thanks in advance.

[DanThe]

Gearbox work is always expensive, what engine/box are we talking about? There is also the option of using a more modern gearbox

[Vez010]

It’s a Getrag 5 Speed close ratio box from a 325i Sport. My preference is to keep the car as OE as possible to be honest.

[Brianmoooore]

an auto to manual conversion

My preference is to keep the car as OE as possible to be honest.

???????????????


It's unusual to find an E30 gearbox that needs more than a replacement seal for the selector shaft. Bung it in and see.

[reggid]

Gearbox work is always expensive, what engine/box are we talking about? There is also the option of using a more modern gearbox

it really would be good if there was a decent 6sp swap for E30'swith m20 engines

[BenHar]

Gearbox work is always expensive, what engine/box are we talking about? There is also the option of using a more modern gearbox

it really would be good if there was a decent 6sp swap for E30'swith m20 engines

Why?

The M20 has a wide enough torque curve not to need it. First is almost unnecessary and fifth takes you way beyond legal speeds.

Ben

[reggid]

Gearbox work is always expensive, what engine/box are we talking about? There is also the option of using a more modern gearbox

it really would be good if there was a decent 6sp swap for E30'swith m20 engines

Why?

The M20 has a wide enough torque curve not to need it. First is almost unnecessary and fifth takes you way beyond legal speeds.

Ben

to be able to cruise at freeway speed without a shedload of revs, sure you can fit a longer diff but then you make it less responsive from a standstill thats why i said "decent" its not just about having 6 ratios or having them closer

the first 5 ratios in a 420G from e36 m3 evo wth 3.15 diff are almost idential to the G260 from a 325i sport with 3.91. So the top gear in the 420G would make cruising much nice at 70MPH as essentially it has 1 extra overdrive. The ratios themselves are not any closer in this instance though with 6 speed i'd want the 1st to 2nd chnage to keep the revs a bit higher to keep the engine on the boil better than what factory chose.

with a standard G260 if shift at 7k in 1st and you're at sub 4000 rpm into 2nd which is pretty shit TBH as with stock limiter it's "off cam" which is actually "off intake manifold" but i digress , the CR sport 260 is like 4,250 rpm which is about the lowest you'd want IMO

[BristolE30]

I think the Getrag 260’s are pretty solid man. I’d drain the oil and replenish and then wack her in

[Vez010]

I think the Getrag 260’s are pretty solid man. I’d drain the oil and replenish and then wack her in

Thanks mate! Appreciate your response.

[Vez010]

an auto to manual conversion

My preference is to keep the car as OE as possible to be honest.

???????????????
That was in response to installing a modified box although I appreciate the contradiction of keeping things OE and saying I want to convert from auto to manual.


It's unusual to find an E30 gearbox that needs more than a replacement seal for the selector shaft. Bung it in and see.

Thanks Brian!

[paultv]

I switched my 3:73 LSD for a 3:46...first is a little more useful...and I can't tell any difference in its ability to accelerate, but the motorway experience is much better...90mph at 3500 rpm....cruising at 80mph is very comfortable and thats in a cab which is heavier and noisier to drive, so I'd say the m20b25 and Getrag are well matched with a good power curve allowing a variety of ratios to choose from depending on your needs.

Paul

[HJ1981]

Shame, i was hoping someone knows the insides of these gearboxes with experience replacing syncros, bearings, shims etc

Bentley manual shows practically all you need, still would had liked to see someone actually rebuild one.

[flybynite]

Shame, i was hoping someone knows the insides of these gearboxes with experience replacing syncros, bearings, shims etc

Bentley manual shows practically all you need, still would had liked to see someone actually rebuild one.

Cant say I really know the gearbox but I replaced the rear bearing on mine and another (seemed to be a weak point on the early ones) and it is a complete strip to get to it. Rebuilt it using nothing but the Haynes and it did another 70 odd thousand miles after in silence so cant have got it that wrong.

Better than the 245 it came with which was made of cheese.

it really would be good if there was a decent 6sp swap for E30'swith m20 engines

Anyone looked at the E46 diesel 6-speed? I remember being careful because it is the same gearbox as the 330 petrol but different angle on the bellhousing, nearly bought one by mistake.

If it is wrong for the M54 (M50,M52) is it correct for the M20 or wrong for both?

[reggid]

Shame, i was hoping someone knows the insides of these gearboxes with experience replacing syncros, bearings, shims etc

Bentley manual shows practically all you need, still would had liked to see someone actually rebuild one.

Cant say I really know the gearbox but I replaced the rear bearing on mine and another (seemed to be a weak point on the early ones) and it is a complete strip to get to it. Rebuilt it using nothing but the Haynes and it did another 70 odd thousand miles after in silence so cant have got it that wrong.

Better than the 245 it came with which was made of cheese.

it really would be good if there was a decent 6sp swap for E30'swith m20 engines

Anyone looked at the E46 diesel 6-speed? I remember being careful because it is the same gearbox as the 330 petrol but different angle on the bellhousing, nearly bought one by mistake.

If it is wrong for the M54 (M50,M52) is it correct for the M20 or wrong for both?

i think the ratios are all whacked up for a NA petrol from memory but i think it is a candidate did read about on one the forums

[Brianmoooore]

My brother in law has fitted a six speed to his 2.8 Z3, and I'm fairly sure it came from a diesel.

[HJ1981]

Shame, i was hoping someone knows the insides of these gearboxes with experience replacing syncros, bearings, shims etc

Bentley manual shows practically all you need, still would had liked to see someone actually rebuild one.

Cant say I really know the gearbox but I replaced the rear bearing on mine and another (seemed to be a weak point on the early ones) and it is a complete strip to get to it. Rebuilt it using nothing but the Haynes and it did another 70 odd thousand miles after in silence so cant have got it that wrong.

Better than the 245 it came with which was made of cheese.

it really would be good if there was a decent 6sp swap for E30'swith m20 engines

Anyone looked at the E46 diesel 6-speed? I remember being careful because it is the same gearbox as the 330 petrol but different angle on the bellhousing, nearly bought one by mistake.

If it is wrong for the M54 (M50,M52) is it correct for the M20 or wrong for both?

Good to know, but after checking with my local dealership, i believe all syncros and bearings would run around €1.200+ and still all the seals and what not to be added. But it is nice to know, you used the manual and it was just fine, or did you find some conflicting specs in the manual?

[flybynite]

Good to know, but after checking with my local dealership, i believe all syncros and bearings would run around €1.200+ and still all the seals and what not to be added. But it is nice to know, you used the manual and it was just fine, or did you find some conflicting specs in the manual?

Well it is getting on for 30 years ago since I rebuilt them so forgive me if i forget some of the details

I did not get involved with messing with the rest of the internals ,just took them out and put them back the way they came out.

The failed bearing was allowing play that was causing all the problems. Neither gearbox was particularly worn, Once it was replaced everything went back where it was and the gearbox worked as it should.

Can't remember thinking it was difficult to replace syncros etc while everything was out. Just need to be clean and methodical.

Problem is a good gearbox specialist can often do the job cheaper than parts direct from BMW. If it is that bad probably better off just finding another good gearbox?

[HJ1981]

Good to know, but after checking with my local dealership, i believe all syncros and bearings would run around €1.200+ and still all the seals and what not to be added. But it is nice to know, you used the manual and it was just fine, or did you find some conflicting specs in the manual?

Problem is a good gearbox specialist can often do the job cheaper than parts direct from BMW. If it is that bad probably better off just finding another good gearbox?

I believe that is the catch ;)