Gear change issue - gotta be simple

[Bear157]

Well the engine / transaxle exchange into my #157 Alfetta sedan race car is almost complete. However, I have one little niggle....well, not so little if I want to use more than one gear in a race.

After connecting everything up, getting the engine running (how cool do 45's sound with the Alfaholic extended alloy carbide mounts?), brakes bled, clutch bled (bit of a hassle, but with the help of a bleeding suction device, all good), we still have a problem. I can only select gears with the car turned off. I can use the clutch to take off, but not to change gears.

My question is, does this sound like an easy adjustment fix? Am I missing something? I just don't think the other drivers will agree to race with just one gear.

[Cool Jesus]

Hmmm, could the selector fork at the transmission be wrong? Or you could offer it as the pace car for events 
I think there was more than one style of selector fork. Can you post some photos of the linkages? What year models are we looking at for both car and replacement tranny?
Was the tranny in working order or did it have some work done to it?

[Storm_X]

The shifter arm off the gearbox is one spline out.

[Bear157]

The whole Transaxle (originally out of a 75), selector linkage, gear stick, and engine were also in an Alfetta sedan. So, it was a straight swap. Clutch engages enough to move car. Storm, can you please expand? How could it have been out when it was fine in previous car (working perfectly in that car).

[Storm_X]

Was the arm off the gearbox ever taken off at all ?

[Mick A]

Hi Bear,

You say you cannot select gears with the engine running.

Does this mean that it just grinds? As if the clutch weren't pressed? Or you physically cannot move the gear lever?

As much detail as you can please, and hopefully we can be of more assistance!



-Mick

[Mick A]

The shifter arm off the gearbox is one spline out.

Hi Storm.

What makes you think that mate? Back up your diagnosis please.

[minipete]

Sure sounds like the clutch is not disengaging completely. 

When you engage gear then start the car does the clutch take up near the floor?

[Cool Jesus]

Any luck on the diagnosis Bear?
Not wanting to state the obvious to anyone, but thought I'd put this out just in case others  come across this issue and need some diagnosis advice. I have this info on file, having obtained it from somewhere on the web. In any case I think its quite relevant to your predicament as others are also leading towards this.

It certainly sounds like as others have stated that the clutch isn't disengaging, more so than a linkage problem as I first thought.

If the clutch does not release completely when the clutch pedal is fully depressed, the disc will continue to turn the input shaft. This may prevent the driver from shifting gears, cause grinding when the gears are changed, or cause the engine to stall when coming to a stop.

Bear, are you able to change into first gear from neutral?

With transaxles a clutch that won't release may have misadjusted linkage, a leaky or defective slave or master clutch cylinder, air in the hydraulic line or cylinders, corroded, damaged or improperly lubricated input shaft splines, a worn pilot bearing/bushing, bent or worn release fork, bent clutch drive straps, bent or distorted clutch disc, a clutch disc that was installed backwards, or mismatched clutch components (if the clutch was just replaced).

Other things that can cause the clutch to drag or not release include heavy gear oil in the transmission that's too thick for cold weather, defective or worn clutch pedal bushings or brackets, or flexing in the firewall or any release component attachment point.

Often an apparent clutch problem really isn't the clutch, but the clutch linkage or something else, which is what I was first thinking off as its the easiest to rule out. Alfas have a hydraulic clutch linkage with a master cylinder on the clutch pedal and a slave cylinder at the clutch bellhousing. The internal piston seals on the master and slave cylinder can develop leaks that allow a loss of pressure when the clutch pedal is depressed. This may prevent the clutch from disengaging or allow it to engage prematurely (as when sitting at a stop light with the pedal all the way in). You mentioned it was a hassle to bleed the clutch hydraulics, does it feel soft and have less than normal resistance? Slave cylinders develop leaks more often than master cylinders because the slave cylinder is the lowest point in the system. Any rust or dirt in the hydraulic fluid is therefore more likely to settle in the slave cylinder where it can cause seal problems.

Storm, I to was also thinking it was an Alfetta tranny, but I think we are looking at the 75 box with an isostatic  control assembly for gear changing so its not the splined lever. Is that right Bear?

I've also attahced the clutch troubleshoot guide from the 75 which summarizes the above.

[Neil Choi]

If it is the hydraulics, you can get underneath to watch the action of the slave cylinder move or not move while someone pumps the clutch pedal for you.  This will indicate either slave or master.  My 2 cents as I lost clutch a few times, hydraulics being the simplest to look at and fix (at the race track).  But give your hydraulics another good bleed. 

[Bear157]

Hi guys, sorry about the lengthy delay in replying to all of your helpful theories and questions.

Since my last post a few things have happened and been attempted. Given the issue with the bleeding, I removed the master and slave cylinders and sent them off for a re-kit. I then re-installed them (the slave cylinder install is fun, huh?) and the system bled up beautifully and without any issue. However, I was still presented with a grind when I attempted to put it in any gear when the engine was running. Again, with the engine off, I can change gears, put it in first/reverse (or for that matter, any gear) and then start the engine, let the clutch out and the car will drive off.

One thing that might be a positive, is that I did a few runs back and forth (turning off when I stopped, putting into gear and then restarting in new gear, then taking off) and it started allowing me to change gear when I had the engine running. The trouble is, when I turned it off, I was back to the old problem.

Just to answer a couple of questions/theories: the transaxle (75 TS) was removed as one complete unit from the donor car and nothing was removed (clutch bell housing, gear selector, etc); I replaced the rubber clutch hose with a new one from Alfaholics; I changed the gear oil with quality Penrite oil; and I have been using quality DOT 4.1 brake fluid. We even tried putting some washers as spacers (2 on each bolt...more fun) between the slave and the mounting to try and get an extra few mm movement, even though it appears to be moving quite freely.

I am going to take it off the trailer today and do some runs up and down the drive to see if I can get it to free up again like it did that one time last night. I am entered to race tomorrow and that is the last thing left on this 5 month rebuild project. The secret, they say, to making a small fortune out of racing is to start with a larger one. I'm not sure about that, but my hairdresser has started suggesting grey colours...whatever that means LOL.

[Bear157]

Well, good news. I found a stretch of bitumen to give the car a blast on and we now have gear changing happening. I can only think that there must have been some sticking happening as a result of the box sitting for 12 months without use before finding its way into my car. I am off to Queensland raceway tomorrow to have a run in a sprint event so that I can give the car a 'shakedown' before the race season starts on the 23rd.

A huge thanks again for all the input and advice. Here's hoping all is OK now.

[Bear157]

Well, the good news is that the gearbox held up well...well, for the 4 laps at 75% pace that I did. Unfortunately, the flywheel has decided that it has had enough of this engine and with a wild bunch of noises, has sheered all bolts and a replacement is now in order. I'm not sure if it is related, but we also discovered that the harmonic balancer has a large split in the key slot. Fortunately, I have spares of both and the engine appears to still have great compression, so hopefully the only reason for pulling it back out is to replace the flywheel. Crazy business this racing stuff.

[AikenDrum105]

Hi Bear,   

I had a similar issue with a 105 not long ago,  and it was the pilot bushing seizing up on the nose of the input shaft.  Was enough resistance to make the synchros miserable and symptoms just as you describe.  At the time it surprised me that was the cause.

I ended up popping the bushing out, cleaning dried up clutch material and grease out of the bushing hole and polishing up the nose of the input shaft - a new pilot bush with a smear of engine oil on the inside and all was well.

I know, I know - transaxles are different  - you're looking for the pilot bushing marked here as #9



The pilot bushings are usually sintered bronze - They're porous and have oil wicked into them during manufacture. if they've dried out on a shelf or during use,  you might do well to give it a quick boil up in some new engine oil for a bit to saturate it again.

You probably knew all that already,  but just in case .... 

*edit*  Just realised Cool already mentioned worn pilot bushing awaaaaay back in the thread    


Cheers,

[MD]

Ocassionally during extended humid weather combined with a prolonged storage of a car can result in a binding up of the driven plate due to rust developing on the pressure plate and flywheel.

Naturally, this means that the box is continually being driven and no shifting is possible.

The fix : a good burnout..