On my way into work one morning about 3 weeks ago I started to notice a louder whine from the differential.
As it was a Friday, "no problem" I thought.
I'll drive the rest of the way in, drive home and investigate over the weekend.
As I was going round a roundabout there was a very cloud clunk from the rear and it sounded as if a driveshaft had snapped and was flapping around smacking the underside of my car.
I pulled over, called the AA then looked under the car to inspect the damage.
At first it looked quite minor, just a bit of oil seaping from one of the driveshaft seals on the diff, but the more I looked the more I could see oil flung around the underside of the car.
I got the care rear towed home and started looking for a replacement differential.
The long and the short of it is that this turned into far more of a pain than I thought it could ever do.
After some googling and understanding that the 1.6 only came with an open differential or VLSD, I ordered a "replacement" VLSD off the internet. (Diff 2)
It turned up looking worse for wear and missing the stub shafts, but no matter. As I already had an LSD "it'll be a one-to-one swap".
I had no idea how wrong I was.
What I took out of the car (Diff 1) did not resemble a VLSD, but it didn't match the description of an open differential either.
The stub shafts were wrong and it didn't look like a 1.8 differential either.
After a lot more reading I discovered that this was likely a MazdaSpeed differential which would make sense as there were other MazdaSpeed parts and branding on the car.
Unfortunately this did mean that I now couldn't use the shafts in the replacement differential (Diff 2) and would need to order the right shafts.
After looking around on the internet with no success I started to investigate the replacement I'd bought.
It was sold as a 1.6 VLSD and came in a smooth case which I wasn't expecting but my understanding now is that there were a limited number of VLSD's that came without fins.
However, the diff was in far worse shape than the pictures made out and would need a whole lot of work and replacement seals/bolts/plugs/bushes etc... before I could even consider using it, let alone the shafts.
At this point I called a well known new/used parts retailer that I've used frequently and he found that he did have a suitable VLSD diff in stock with the required shafts included which I promptly bought. (Diff 3)
This arrived a couple of days later and while it was covered in rust and looked like it had spent some time under a tree, the seals and bushes were good and while the plugs took some work to remove, the threads were in good condition.
Admittedly the swarf that came out on the magnetic drain plug didn't look too good but I simply needed to get the car back on the road ASAP.
Based on more advice from the internet I determined that this wasn't abnormal if the diff had never had the oil changed so I filled it with 75W-90 and drained it to get the crud out and went ahead and fitted it.
With everything bolted up and torqued to spec I added the required ammount of Mobil 75W-90 and took it for a test drive.
I didn't get far before turning back as something was still not right at all.
I put the car back in the air and ran it in first and there was a nasty grating noise coming from the passenger side.
This is where I made a stupid and impulsive mistake.
I assumed that there was no way the replacement differential could be the problem and started looking to see what else could be at fault.
I quickly ruled out the breaks and settled on the driveshaft CV joint as the culprit.
A couple of days later I was the proud owner of another passenger side assembly as the driveshaft was overly comfortable in it's home and didn't want to leave even with repeated persuasion.
With everything fitted and torqued again I went for another drive.
After driving for a while things did initially seem better.
The diff did feel slightly "clunky" but I assumed this was normal-ish.
However, after driving to work and back the following day, the illusion that everything was sunshine and rainbows was slowly whittled away and I had to admit to myself that it really wasn't right.
After taking another look at it and comparing to pictures on the internet I'm now 75% certain that it isn't a VLSD either as both of the stub shafts have identical flanges which appear to be from the standard open diff.
It does act like a real LSD when driving (when it doesn't make a clunk sound) so I suspect it either has clutch-type insides or is something else entirely.
I booked the car in with my local mechanic to take a look and got the verdict back a couple of days later that it was the diff (Diff 3) at fault.
At this point I have the broken "original" MazdaSpeed differential, a replacement smooth case VLSD differential without the right shafts and a third faulty differential in the car that I'm now very nervous to drive with.
As you can imagine I'm not in the best of moods.
I've contacted the seller of Diff 3 to see what can be done.
I'm not naming them here as I know these things happen, especially with used parts, and having had nothing but fantastic service from them in the past I'm confident that they'll sort it out.
I'm currently trying to figure out what I want to do moving forwards.
le sigh