teeth of ring gear are being torn from the torque converter

[werchipper]

Following on from post titled "Starter spins but doesnt engage"

Help needed with a T25 1988 autobox (010), I’ve had the gearbox rebuilt using the std VW overhaul kit and it has worked after overhaul but I seem now to be in the situation where the starter motor is ripping the ring gear off the torque converter. Initially I thought it was the torque converter at fault but this has been repaired and the same thing happened again. I now suspect that even though the gearstick is in neutral or park there is something in the gearbox that is engaging drive so the torque converter is in gear when the starter hits it and therefore ripping ring gear from its spot welds. I’m not a mechanic but I trying to work my way out of this problem, any advice Or anyone had a similar problem ?

I also have a second hand torque converter i will be installing. although i believe it should work as it came from a working van. i am concerned about getting "foreign" bodies in the automatic transmission. Am i being overly cautious?

Russ and Nigel

[R0B]

Very few on here have an understanding of the auto box.Have you tried asking on the samba website.The yanks are more likeley to give you an answer, as they use the auto more than we do.

[937carrera]

That's a fair point, and I know I don't understand auto boxes, but I have done a gearbox / engine swapover on a transaxle tiptronic, (and about to start another on FWD car) so a few thoughts from my limited experience.

If you think the problem is that the box is in gear when the stick says park, that's a physical problem with the linkage or an internal box fault. Changing the torque converter isn't going to change that.
It's fair to assume that cleanliness is next to godliness when doing the torque converter swap,so clean and prep the replacement well, make sure the box is vertical to avoid transmission oil loss

As well as Samba try Vanagonauts

[bigherb]

First, check the starter motor mounting faces are clean, no corrosion making the starter sit out of line. Check the starter motor mounting flanges are not cracked causing the motor to twist out of line.
The starter motor has to motor round to engage the teeth before the solenoid contacts close, which uses around 30A through the ignition switch any voltage drop and the teeth may have trouble engaging initially. Fit a starter relay to eliminate any voltage drop. Yes, you must be scrupulously clean and replace the torque converter oil seal as a precaution.