Buying a used tranny

[aabdelhamid]

My car is a manual 520i built 1990. I need to change the tranny due to excessive noises and grinding. any idea how I can inspect the used tranny I am buying to make sure it is OK. My mechanic tells me, I have to install and run the tranny before I can get an idea about its condition. This is very time and money consuming as he will get paid for this work as well. Wht do you advise me

[Dave M]

Fairly common problem. Need a tranny, try one, then another :( May just have to have faith.

Sorry, can't help you with an 'out of body diagnosis', out of my league, but someone here migh be able to help if we keep it bumped ;)

Out of interest, is that ZF ....310 tranny? It seems pretty low mileage for having issues.
Dave M

[Ross]

Very few sellers will be willing to open one up for your perusal anyway. A look at the oil tells a bit. Metal in it is bad of course, look for "sparkles" .
A lot of wear on the input shaft where the clutch disc rides is an indicator of high miles too.
Also seeing the car it came from is helpful. If the car is a POS chances are so is the trans.