5 Speed Transmissions

jhjacobs

jhjacobs

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My coupe has been enhanced with a 5 speed transmission from a later model car (presumably a 5xx). This is a welcome upgrade but I am not sure exactly which transmission it is and I am going to have to pull it soon and replace the input shaft bearing. So, does anyone know what transmission this is likely to be and what year / model it could be from? I need to look up and order gaskets and bearings...
 
There could be three possibilities - the most common and probably the most desirable would be a 265 which would be an overdrive in fifth gear, it has a two piece housing, with reverse being in the upper left. The other two would be a 260/6 which would be a one piece housing and from what has been discussed here and in other forums less robust - the third being a close ratio box commonly referred to as a dogleg, as reverse and first gear are in the same axis with second and third and fourth and fifth on their own respective axes.

Let me know which one and I would be able to tell you the original application.
 
From your description is sounds like the 265. It is clearly an overdrive; a marked improvement over the E3 I owned years ago with the Getrag 4 speed. Reverse is also in the upper left. I don't know about the housing; I hope to find the 2 piece because it is much easier to pull.

The last time I replaced an input shaft bearing it was on my old E3 in January, subfreezing, in the driveway many, many years ago. It involved multiple busted knuckles and considerable cursing. However, a $20 bearing and $3 seal made it quiet again.
 
If your car has a speedometer driven by a cable, as opposed to some sort of electrical arrangement, the transmission is a Getrag 265 as others have mentioned.
 
Thanks for all the advice; gotta love this forum! I properly educated now and I definitely have a 265. I have a copy of the BMW ETK software so I can easily find the part numbers. What I don't have is the full pedigree of the car and I know it is not a purebred. Confirming that it is a 265 will make the part location much easier; I found it listed under mid 80's 535i (M28) models.

My main objective is to replace the input shaft bearing. It makes a slight grating noise when being driven and when in neutral. When depressing the clutch while stopped in neutral the noise continues for a second or too and goes away (as the input shaft load is decoupled). I am confident with the diagnosis because it is identical to what my E3 did in 1979. After removing bearing with a press it only had a tiny little pit barely noticeable with your fingers but it sure made a racket...

I'll definitely replace the input shaft seal and probably replace various other seals while the unit is out of the car. I've also got a new hardy disk (rubber donut) and center support bearing / carrier for the drive shaft. The transmission seems to be perfect in every other respect.
 
Decoupe
The sounds could also be from the throw out bearing.
For $30 or so replace it while there with the trans out.
And since you were the one that advised me, when I was doing a trans reseal, to apply sealer to the input cover!!! I won't tell you to do it.
The article writen by Devinder covered most of it well.
steve
 
Good point, when I'm in there I will certainly replace the throughout bearing. I'm pretty sure this is not the problem source since when the clutch is depressed with the car stopped but $30 worth or preventative medicine is a good idea. Bad throughout;s normally manifest their problems when the clutch depressed and they have a load. I'm pretty confident in my diagnosis since I've done this job before for the exact same reason.

I will also replace my clutch and pressure plate if the is any sign of wear and, I'll have a look at the flywheel to see if it needs to be resurfaced. Pulling the transmission is not my favorite job and I would rather buy and replace any suspect stuff while I am in. At the same time, I really don't want to crack the transmission itself open any more than needed.
 
Regardless of the mileage, replace the pilot and throwout bearings, the pivot post, all of the seals on the input shaft and the selector rod seal. Consider replacing both the flex disc (use the manual type not the automatic) and the centre bearing if you don't know when last done. All of this should be about $250 - 300 including a new friction disc and pressure plate if decide to refresh to clutch. Cheap price for peace of mind.

Also consider sending your flywheel out to have it lightened about 40% - cheap performance upgrade at $150 +/-.

Oh yeah, make sure you use the varnish compound on the input shaft housing or you get to pull the whole thing a second time to stop the leak!
 
I'll make it a point to do all of the changes; price is not major consideration. However, two things I don't understand:

1. Varnish on the input shaft housing? Cleaning the surfaces and using a new gasket isn't sufficient? It was fine last time I did this. What am I missing?

2. Lightening the flywheel makes sense. Is there something magic about 40%? I assume this is done by cutting into the engine side with a lathe so as not to change the surface depth. I would guess this would have the effect of letting the engine rev to full speed faster; but are there undesirable side effects? I alway thought that the mass of the flywheel, counter weights on the crank, connecting rods / pins / pistons, and harmonic balancer were fairly carefully designed to keep the engine smooth and the crank stress relatively even.
 
There are three component shells to the 265 transmission, the bell housing (clutch assembly), the transmission housing (the gears and synchros) and the housing cover (that fits over the input shaft).

There are two models of the 265 - 265/5 and 265/6. One main difference between the two is the 265/5 has a gasket between the transmission housing cover and the main housing and the 265/6 does not. Probably other differences as well.

I have the 265/6 and you smear a coat of gasket varnish or Locktite 573 on to seal the surfaces - at least I should have.

The flywheel is an interesting bit of physics. It takes power to get it moving when accelerating but saves power when cruising/climbing. So you're right about spinning up faster versus smoothness and that balance is maintained (based on what Metric Mechanic and Top End Performance say) even after removing 40% of the original mass.

I've had two cars done and notice the improvement more in the lighter vehicle. No problem with smoothness in either but i wouldn't put in a 6 -8 lb racing flywheel into a road car for the same reasons you mentioned as well.
 
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