Secondhand VW T3 gearbox buying guide
This secondhand VW T3 gearbox buying guide has been put together to give you a quick few things to look for if you decide to buy a secondhand box and will hopefully save you money and some heartache.
Most T3 gearboxes are around the 30 year old mark and may have been subject to a general lack of maintenance, no oil changes, various driving styles, wear, worn shifting, corrosion. Some have been rebuilt incorrectly leading to more damage. Buying a secondhand gearbox is a risky business and if you get the wrong one it could potentially cost more in the long run than a gearbox rebuild. However, it is good to have a backup.
Check the box for leaks around the output flanges, reverse switch housing and bell housing. Look at the end case for corrosion, five-speed T3 gearboxes have a habit of the end case corroding away.
Check the code is it suitable for your engine? The gearbox code can be found here
Some boxes are high revving some low and are for either petrol or diesel vans. Which ratios suit your engine better. Petrol bell housings and input shafts are different so have to be changed if you are using a petrol box on a diesel and vice versa.
Does it select all gears if it doesn’t it doesn’t work
Drain Plug Magnet and Oil
Ask if you can drain the oil and look at drain plug magnet. Often the best indication of the condition of a gearbox is to inspect the drain plug magnet a good one will have clear oil and a sludgy stem. A bad one will have chunks of metal will falling out. Sometimes people drain the oil and wipe off the magnets be wary of this. More about this here https://vantopia.ie/vw-t25-t3-syncro-gearbox-drain-plugs/
Get it checked out
Get it checked over by a gearbox builder who should be able to do a top and tail on it. You’ll be able to get the backlash and have a look at the crown and pinion. Then at least you’ll know what you have.
Hope this is of help