lol, they will interchange.

 

Feeling inexplicably Pollyanna-ish, I continue to seek a silver lining in this darkness and decided to consider this speedo gear problem an opportunity instead of the insult it is.
I ran up to Advance and luckily snagged the last of the Valvolene gear oil that was being discontinued, so I now have 10qts. purchased for a mere $9 and that makes it cheap enough to use as a solvent/flush for the new box.

The trans is sitting on the bell housing and once the tailshaft housing is removed, I'm going to fill the whole thing to the brim with oil, spin it around some and generally let it marinate for a day or so. Then drain it out, see if there's any grotesque debris and if the box spins more nicely.

That's my story and I'm sticking to it...until I don't.

 

This is purely a suggestion. When I change transmission oil, diff oil, and even engine oil, I go for a good drive to just not only thin the oil with heat, but to stir it up and any small debris that might be in there.

Maybe grab a few beers and hang out for a while with some sorta crank, drill, whatever and spin the transmission for a bit. I think doing this while up on the bell housing and then right before draining when it is in normal position would yield best results.

This leads me to another thought. With a nice cheap supply of oil, why not actually use auto trans fluid or mineral spirits for the cleaning? You have plenty for a couple of changes afterwards to get any residual cleaner out. Actually, there is thread on here somewhere that talks about mixing auto trans fluid and the proper stuff to improve shifting.

 

It sure would be nice to take a peak inside that S4 trany. Anyway of getting a borescope camera in there? It would think you can use something like AFT fluid in there to help clean out the junk - also long as the synchros are brass and not carbon paper lined.

It may also be time to start looking for a better S5 trany or have someone rebuild yours.

 

With your description of storage methods and ease of rotation, my main concern would be surface rust and pitting on the tooth faces and bearing races, which makes for some noise when put into use.

 

They are brass (or,more likely bronze). I don't think the carbon lined or carbon ones were in play at that time. Maybe someone else can say for sure.

 

the synchros are brass. the gears are iron. shafts are steel.

depending on when the trans was made, and or if its been rebuilt it may have a sealed bearing or two, but the rest will be just regular ball bearings.

 

I'm sticking with bronze, it looks just like brass though.

 

Well, the hybrid trans is back in one piece although it fought me every step of the way.
I don't know why I have such a mental block about them, but transmissions are a black art and I've so far managed to avoid anything more comprehensive than replacing front and rear seals...until now.

The S5 tailshaft housing drops right on the S4 gearbox although I doubt the reverse is true.
The whole procedure for removing the shifter block I found completely non-intuitive and frankly, baffling. It makes a certain amount of sense once you have it all apart and see the actual mechanism but unless you've done it before, that knowledge isn't available to you and the FSM is woefully vague.

For some reason, my FD VSS did not want to engage the drive gear...it was weird because the original speedo drive fell right in but mine would not. Until suddenly, it did.
Possibly a miracle, I'm not questioning it.

Soaking in oil overnight improved the feel of the gears a lot, it now spins nicely and I screened the oil as I drained it and found nothing alarming.

I spent some time cleaning up the exterior, not a lot but it's not filthy anymore and looks ok.
Certainly clean enough to spot any leaks.

I'm not sure if it can be left on during install (anyone know?) but I'm putting the shift lever on now, just to verify I can get all the gears. I read it's possible to have 1st>4th but be locked out of 5th and REV and I sure as hell don't want to mess with the shifting again from inside the car.
It's drying in the sun now, later I'll finish up and try to install tomorrow.
We have one more day of 70° temps before it goes into the forties and rain this weekend.

 

I believe the only issue with 5th and Reverse was if the reverse switch didn't go in properly

You should be able to just snug the shifter, clun it through the gears to be safe, then take it back out. I have a feeling if you left the shifter in while trying to install your gonna hit the underbody with it while trying to line it up with the engine then be cussing yourself because you gotta drop it back down and remove the shifter

Aka, don't take the chance of making it harder on you

 

This is what hell looks like to a privileged American:


And this is what I went in for:


All ready to install.
Manana.

 

You will not likely get it in with the shifter mounted. I found it difficult enough when I did my clutch back in July without the shifter. The engine needs to be tipped back as much as you can manage, to align the input shaft with the crank/pilot bearing as you raise the trans up nose high to get it in,and even then, the tail housing and the shifter pedestal want to hit the tunnel until you can slide the input shaft home and raise the tail of the transmission, and get the crossmember under it.

 

Figures, dammit.

 

I'm rather surprised, I got the trans in all by myself.

Sigfrid was coming over this weekend to help me out but our weather is changing and I had nothing better to do, so I figured it was worth a shot.
I probably spent more time smoking bowls and planning a strategy than really working but in the end it went on in one try.
*thunk!*

The trick was studs, two of 'em, screwed into the bottom bellhousing bolts.
The studs were about 3 1/2" long (one of them MUST have a screwdriver slot in the end to remove it) and allowed me to correctly orient the bellhousing before the input shaft began engaging the clutch. With the bellhousing hanging on the studs (but NOT the input shaft) I was able to jack at the tailhousing to get the engine>bellhousing parallel and basically, just shove it home. I had a ratchet on the main pulley and just a small turn aligned the splines and the trans was in.
Very drama free.

Naturally there are still a bunch of things to bolt back in but the hard part is done and I'm rather chuffed.

 

There is nothing more satisfying than the sweet sound of *thunk* when it comes to transmission installs.

 

I agree.
Especially when your friend doesn't think you can do it.

 

I've been there. Usually I can get a hand with a transmission install, but one of the last ones I did was on a Jeep with the transfercase and front driveshaft still attached. I was too lazy to unbolt them. Made the assembly about 200lbs heavier it seemed.

 

When we work together, Sigfrid usually does the more physical stuff...because I'm old and smart.
Now he knows I've been sandbagging and my free ride is probably over.

What's really gonna get his goat is that I did it without injury...so far.

 

Great news. Did you happen to replace the pilot bearing/seal?

 

No, that was all new in July when the alloy flywheel and clutch went in.

 

I sorta regret not doing a lightweight flywheel when I did my clutch. Did it improve performance much?

 

In terms of hard numbers, I kinda doubt it but it absolutely changed the driving experience for the better.

 

The flywheel is just an energy storage device, you dont gain horsepower by making it lighter.

https://en.wikipedia.org/wiki/Flywheel

 

Yes but, if my physics serves me right, during acceleration, if less energy goes into spinning up the mass of the flywheel, more energy goes to the wheels to accelerate the car. I suppose if someone wanted to take the time, they could figure out exactly how much. If one knows the inertial center (theoretical center of mass) of the flywheel. It's not the outside diameter.

 

But a lower mass flywheel does increase the rate at which the engine can accelerate or decelerate which has a big impact on overall feel of the engine and its throttle response. It also has a direct and measurable impact on timed acceleration runs of the car. How can this be you ask if is does not "make any more horsepower"? First understand that the engine has to accelerate both the mass of the drive train and the mass of the car. By using a lighter weight flywheel you have reduce the load on the engine by reducing drive train mass, so now there is more torque available to accelerate the mass of the car. It produces a similar net effect to when you reduce the weight of the car.

There are some equation here for examples of some BMW models for reference purposes;
How a lightweight flywheel works

Just remember that there are always trade-offs. A light weight aluminum flywheel is really trick on say the road course or at the drag strip, but it can be a royal PITA during a bumper to bumper stop and go traffic daily commute. You may also have to be talented at heal toe shifting to keep things rev matched for a smooth fast shift. Engine idles speed will be effected to a great amount with an aluminum flywheel by the varying loads on the engines due to things like; when the PS rake is cranked to full lock or the a/c compressor cycles off and on. (remember those things are usually not found on a real track only race car). That is why a mid level weight billet steel flywheel is usually the best compromise for a daily driver or a car driven mostly on the street. A factory heavy weight cast iron flywheel gives the smoothest idle characteristics and allows for smoother slower speed shifts as well.

As always personal preference is just that, personal.