Strange Gearbox Problem

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randall977
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Strange Gearbox Problem

Post by randall977 »

I've been trying to start the engine of my 1982 635 CSi, dogleg manual - and it seems that I can select gears (1st and reverse at least) without it making any difference - as in is turns over as if not in gear. When I got the car I noticed there was a new gearstick linkage kit and slave cylinder in the boot - I fitted the new linkage as well as replace the bottom section of the gear stick, various bushes, mounts etc. How can a gear be apparently selected but the engine turn freely?

The gearbox is a dogleg Getrag (not sure which one 260 or 265?) - the old gear linkage had a welded angle in it - reverse seemed very far over. The new linkage is correct according to the parts book...but straight and possibly slightly longer - positions look better than before.
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Re: Strange Gearbox Problem

Post by Pod »

Do you mean that if you start the car in gear with the clutch engaged, the engine will run, but the car will not move?
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randall977
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Re: Strange Gearbox Problem

Post by randall977 »

Hi, in gear, foot not on the clutch - engine turns over freely... Obviously my thoughts are of major catastrophic mechanical failure but there are no strange noises.

Problem around the selector end? - but it feels like it's selected the gear...clutch plate broken - is this possible?
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hornhospital
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Re: Strange Gearbox Problem

Post by hornhospital »

Do the other gears engage and move the car?
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Re: Strange Gearbox Problem

Post by wattsmonkey »

Dogleg is a 265/5. Reverse is a LONG way over on these, presumably to avoid embarrassing confusion with first.

My feeling is that it must mean that the gears aren't engaging.

Stupid question: did you buy the car having heard it run, or was it in bits? Is the prop connected??
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randall977
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Re: Strange Gearbox Problem

Post by randall977 »

No, never heard it run but it did turn over. Everything was together but clearly work was intended for the gearbox judging from the spares situation. My conclusion is that the clutch plate must be physically broken...I'm going to take out the engine and sort it once I've started it...
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randall977
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Re: Strange Gearbox Problem

Post by randall977 »

The car now runs, which is great...but the Getrag 265 CR5 needs to come out. The gears won't engage properly and you can push the car when it's in gear - hopefully a clutch issue but could be much worse...

yesterday I put the car on ramps, axle stands at the rear., removed the whole exhaust, prop shaft, starter and clutch slave. The engine is supported and the four large nuts holding on the transmission section have been removed. My plan is to take off the transmission section and then remove the bell housing separately - for size and weight reasons.

I read a good review on removing a 265 this way but now can't find it - anyone know where it is? The transmission is not coming off very easily but I assume it takes a bit of effort to work the shaft out? I'm thinking that I might put a sling around the transmission to help with the weight when it's detached - not sure if this is possible though!

Photos to follow tomorrow - no doubt showing horrific internal damage...as long as it's not to my body :P
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randall977
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Re: Strange Gearbox Problem

Post by randall977 »

This morning I removed the gearbox without injury to myself or the box. I had to do a bit of initial prising to get the transmission free from the bell housing but then it just came free - not too heavy and nice and small(ish). Quite a lot of black from the bell housing and smell of burning. Removed the bell housing and clutch - clutch and flywheel are both damaged but sadly not the main cause of the gearbox problems.

Next step is to get into the box to find out what's gone wrong...

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randall977
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Re: Strange Gearbox Problem

Post by randall977 »

Unfortunately there is major internal damage - looks like the lower bearing failed and took out several of the gears. This is a big blow to the project - what are my options (not including giving up)?

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David Muench
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Re: Strange Gearbox Problem

Post by David Muench »

Give Neil a ring on Monday at All Gears in Worksop near Chesterfield 01909478581 he will give you the options available. I don't know how available the internals for that box are but give him a call and he will be able to sort you out.
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randall977
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Re: Strange Gearbox Problem

Post by randall977 »

Thanks David - I will definitely do that. Parts wise it would need 3 new gears, a bearing, other gears (transfer?) and a middle section of case (5 gear section)...
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Re: Strange Gearbox Problem

Post by Brucey »

eurgh! :shock: :shock: :shock:

Looks nasty. Getrag 265/5 gearboxes are becoming as rare as hen's teeth; they don't last for ever, (they are not super-strong plus folk tend to break them by shifting into the wrong gear at the wrong time, because of the odd shift pattern... :roll: .) they have sporty ratios (good for track use), and they fit lots of other cars because they have a detachable bellhousing. All of which means they are quite sought after.

It just takes one chip of hard metal to break loose in a gearbox like that and if it gets into the wrong place it can smash the gearbox to pieces. Often identifying which bit broke first is impossible. Rebuild costs are likely to be prohibitive, but there is no harm in asking a gearbox specialist; these gearboxes are sufficiently sought after now that they may offer you a good trade for your broken gearbox provided the main castings are OK.

IMHO even with a 3,07 diff the gearing with a dogleg box is a bit short for road (motorway) use; depending on what you want from the car it will certainly be cheaper and it might be a lot better to fit an overdrive type gearbox instead.

Various such gearboxes were fitted to M30s engines with and (latterly almost exclusively) without detachable bellhousings. They all bolt up to your engine. However if you have early motronic (which would be right for an '82 whether it is an E12 chassis or an E28 chassis) it uses two sensors in the bellhousing, which not all gearboxes have. Anything built pre 6/87 (approximately, including all E24 and E28/M30 except 2.5 and 2.8 engines) will have the motronic bellhousing sensor mounts. After that things are a little unpredictable; E34 (and late E24 models) with M30 engines never used the bellhousing sensors, yet cars left the factory with

a) fully machined bellhousing sensor mounts or
b) an unfinished lump on the bellhousing casting which can be finish-machined to provide such mounts, or
c) not even a lump on the casting

There is no rhyme or reason date/model wise that anyone has ever worked out as to which you will find. It really was pot luck it seems.

If you get a different gearbox type then you will also need a different propshaft (if the gearbox length is different which it usually is) and note that the gearshift console also varies with gearbox type; after a certain date they use a different one and you need to have the one that matches the gearbox. The early ones have a sheet metal spine and the later ones have a narrow casting as a spine, that mounts to the gearbox differently. A few gearboxes will accept either type (I think) but most need the right one.

If you crap out trying to find a gearbox with the bellhousing sensor mounts (a once unheard of circumstance, but all the rusty E28 etc donors have gone now...) and you need them then another option is to use a gearbox without, and to convert the engine to use a different engine management system, or replace it with a later version from an E34.

You have my sympathies, that looks like a horrible mess.

cheers
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randall977
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Re: Strange Gearbox Problem

Post by randall977 »

Thanks Brucey, really useful and clear.

My first preference is like for like, though expensive and CR might be annoying at high speed, however, straight swap and original spec for my car.

Second is an over drive type, you're right I have early Motronic with sensors, better mpg and nicer to drive in some ways, cheaper. I think I could sort the modifications as I've now spent a lot of time looking at linkages etc.

I really don't want to change the engine management after the ordeal of getting the engine started - it's the one thing that seems to work well.
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Re: Strange Gearbox Problem

Post by Brucey »

oh, I forgot, the gearbox crossmember and the exhaust support bracket are also specific to the gearbox in many cases.

Also if your car is pre 5/82 (with E12 chassis) then it needs a gearbox with a mechanical speedo drive. Later boxes don't have this option fitted.

FWIW the overdrive gearbox (with the 3,07 diff in Europe/UK) was the standard specification for your car; the dogleg was an option.

cheers
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