505 BA10 gearbox vs BA7

[Beano]

Could anyone tell me the relative strengths and weaknesses of these 2 gearboxes, or direct me to a thread that does? I do know that BA7s were pretty rare in carburetted 505s, and the ones that came out in STIs can't go in sedans because of a different length balance shaft. And I do know that people seem to prefer the BA7, even though it is technically a 504 box with an extension housing. Didn't BA10s have a tendency to stick in gear or something?

Advertisement

[John505]

As far as I understand it, neither the BA7/5 or the BA10/5 is regarded to be as durable as the BA7/4 which is quite hard to kill, even running it with next to no oil!
Both five speeds are regarded to have weak synchro action and for the BA7/5 specifically, 5th gear operation can fail. This indeed did happen some years ago in my 1990 505 GTI manual wagon when there was an unfortunate noise when I changed from 4th to 5th on the highway at speed. I limped home & got the box fixed. They found shattered bits of the 5th gear throughout with damage to a lot of other parts - total rebuild cost $1,600!
You can be unlucky!
The BA7/5 because it is same length as BA7/4 is an easy upgrade in 504 - which I have done. Better for cruising on the open road - less noise!
Dave McBean - you could find the thread - published the information you need.
Cheers
John505

[505 to the max]

I've broken a BA10 with an XN1 motor but the BA7/5 I'm now using has never failed so I consider it as adequate. I posted a thread about 18 months ago asking a similar question and the general consensus was that the BA7/5 is the least strong/long lasting and that the BA10 range was far more robust.
If I may ask, what did the rebuild involve?

[Ralph]

There's some good info on Dave's site:

http://www.geocities.com/davemcbean/...l?997061496590

Matt.