Hyundai Repair: Transmission queries, clutch replacement, clutch system

Question
Hi HT

My 97/98 Accent (Excel here in Australia) has recently been having transmission problems. It has a 1.5 SOHC engine.

When shifting to reverse, I used to often fail to properly shift into gear. The gear knob doesn't push as far back as it ought to and when I press down on the gas a loose sound is made and the car does not move. I usually need to slowly depress (100% whereas before that was not required, just like normal foward gears I don't usually floor the clutch) the clutch then slowly push the reverse gear in as far as possible to get it in gear. Once it does in gear it makes a very heavy low "screech"/grinding sound... the kind of sound you would normally get if you rev the car and then immediately shift into reverse.

I went to two separate mechanics who both couldn't reproduct the same sound (back then I hadn't figure out how to produce the sound or to overcome it - this was a few months ago). However, they advised me that my clutch was slipping and that I needed a clutch replacement (which is true anyway... I could move the car from stationary position in 4th gear, had to often down shift on hills and had problems accelarating at the normal rate). Yesterday, I had the clutch replaced. However, hours after the replacement, the reverse problem I had been experiencing returned and still made the grinding sound. Today, the same problem arose twice, however, on both occasions I did not get the grinding sound. My questions to you are

1) What could be making the grinding sound? Do I need to replace the gearbox or was the clutch just "settling in" in a way? Is it possible that the clutch was creating the sound whilst the gearbox was causing the reverse problem where I couldn't push the reverse gear back enough to make it in gear?
2) I've been advised by both mechanics that I had a hydraulic and not cable clutch system... how do I know that the clutch really was replaced? It feels completely different now and on the day of the replacement, the clutch pedal was extremely soft and "spongy"... it is a lot better today. The only reason why I'm doubtful was because the other garage quoted me around 550-600 australian dollars for the job whilst this dealer only charged me 400. The dealer is in my opinion reputable, they are the Bridgestone Tyre company, except here, they don't just fit tyres etc, they also service cars and do repairs on a daily basis.
3) Is there anything I should be careful/aware of when driving with a new clutch? Is there anything I can do to optimise the clutch whilst it's new?

Sorry for the lengthly questions and thank you for your time.

Heb

Answer
Hi, Heb.  The issue you describe with the grinding if the gearshift doesn't fully engage reverse sounds fairly normal.  Depending on the orientation of the gears within the transmission when you attempt to engage reverse, the gear teeth may not be aligned with the shift hub teeth to allow full engagement.  This is something that, to my knowledge, happens in all manual transmissions.  Your transmission is equipped with synchronizers whose job it is to align the gear teeth properly to allow shifting, but they can only work when the vehicle is in motion.  That, combined with the fact that the reverse gear isn't constructed like the others, is why you tend to only have the problem in reverse.  

What you'll need to do is pay close attention to whether the gearshift fully engages.  If it doesn't, select a few other gears and try again.  This will typically move all the gears a little in the transmission and will help align them.  

This issue will get worse as the car ages from normal wear.  When new, the gear and shift hub teeth have pointy edges on them to minimize the positions where they won't engage.  Over time, from wear, the pointy edges wear and become flat spots.  As the flat spots become wider with wear, the more likely it is that you'll encounter a situation where reverse doesn't fully engage.  I wouldn't recommend doing anything to address this unless reverse doesn't operate at all.  Any work with the reverse gear will require a near-complete disassembly of the transmission.

Based on what you tell me, I have no reason to doubt that your clutch was replaced.  In many cases, the point where the clutch engages will be lower in the clutch pedal stroke after replacement.  Your pedal was also probably spongy because they opened the hydraulic system during repairs and didn't get all the air out.  The fact that it feels better now indicates that the bubbles probably made their way up to the reservoir and out of the system.

The things you can do to protect a new clutch are the things you can do to protect any clutch.  Try not to slip the clutch when shifting or driving.  Do not place your foot on the clutch pedal when not shifting.