I have a MK2 that I've had a spare 020 transmission I've had to change due to 2nd gear syncro shot and I've had one in the past with the rivets break and destroy it, seal leakage problems, etc; all on 020 transmissions.
Are to 02A or 02J transmissions any stronger and have fewer problems from above, other than just because they are newer?
I'm thinking about getting an O2A and trying it. Has anyone had experience with these with a few miles on it?
The 02A and 02J transmissions are both quite a bit stronger than the 020's. They are also much easier to tear-down for service than an 020, in that there are a lot fewer special tools needed.
The 02A in my Corrado VR6 has about 160,000 miles on it now, very hard miles. The car was used in street-stock drag racing for a lot of it's life. That being said, it needs attention- 1st gear is hard to get, 3rd and 5th are vague sometimes. I'm actually amazed that it has lasted this long.
Also, the diffs of the 02A/J still use rivets, and there are still bolt-kits to replace them, though rivet failure is very rare on these. The differentials do tend to break though under heavy use such as burn-outs, etc.. when one wheel is turning much faster than the other under load.
Some people say the 02A's are better internally than the 02J's but I have yet to see any real proof of that, the 02A might have better synchros but the 02J gears are supposedly stronger. The 02A's have a weak shift tower, the 02J design is much better. The 02J's went to a "fine-tooth" synchro sleeve for 1st and 2nd gear starting in 2001 to make it shift smoother, but they are easily damaged (sometimes after one accidental grind) and will prevent 1st from working. Many people will change an 02J over to 02A style synchros. The Dual-Mass flywheel on the 02J trannys is junk and should be exchanged for a single-mass 02A flywheel immediately. The 02A and 02J cases are similar, but both have very different mounting points so the mounts are completely different. On both 02A's and 02J's, you can swap the bellhousing half of the case from a 4-cylinder car to a VR6 back-half if you so desire. (usually done the other way around for different gearing on a VR6 turbo)
That's about all I know off-hand.
Brendan
Add to that that 02a/j are hydro clutches unless you get an expensive cable clutch setup. Their cable shifter, IMO, sucks compare to the rod setup used in 020s. Hydor clutch means replacing the pedal cluster and farting around with clutch master cylinder mounting.