Stripped Drain Plug on Automatic Transmission Pan

[Thymeclock]

This weekend I decided to do seasonal fluid changes on my '09. When I drained the A/T fluid it looked pretty good. But when I tried to reinstall the drain plug I realized there were no threads left on it. That's an "oh, s--t" moment, because you can't drive the car without being able to refill the pan.

This was a rude surprise considering that the car isn't very old and I've only drained the fluid about 5 times at most since new. I've owned numerous Asian cars over several decades and have never seen threads strip out on a drain plug - ever. The heads of drain plugs can become rounded out over years of service, but I've never had the threads strip on one. And no, I didn't cross thread it - this was just poorly machined, apparently.

I tried several parts stores only to be told that this A/T drain plug is not cataloged anywhere. I tried the generic oil drain plug rack, but nothing was as small in size as this plug. After wasting time with that approach I determined that the plug is a M10 -1.50 thread. I went to a hardware store and got a bolt of that size with a sufficient (17mm) head on it. Fortunately I didn't need to use a tap on the pan threads. I cut the bolt down to length, added a nylon washer as a seal and installed it. It worked perfectly and the replacement bolt looks like it is of better quality steel than the original plug.

If this ever happens to you, that's the cure. As I recall the threading seemed to be very resistant when screwing it in or out, right from when it was new.The pan has very shallow threading and the original plug is a joke, as it apparently is of very poor quality steel and/or poorly machined to strip out so easily.

[Daox]

Thanks for posting your fix.

[Thymeclock]

Thanks for posting your fix.

You are quite welcome. It might be worth archiving as a sticky, but that's up to you.

[Beneficiall]

Same thing happened to me, different beginning to the story but same end. Took it to dealer, it was just out of warranty...but then I got invoice after they replaced the pan..said it was covered by warranty....awesome...saved 200..my dealership sure is swell. I get a call back from lady who when picking up car said to me that it was actually covered...she had changed her story..said I owed. Sorry.. You told me it was covered, and I have an invoice saying it was. I'm not paying you a dime.

[Thymeclock]

Same thing happened to me, different beginning to the story but same end. Took it to dealer, it was just out of warranty...but then I got invoice after they replaced the pan..said it was covered by warranty....awesome...saved 200..my dealership sure is swell. I get a call back from lady who when picking up car said to me that it was actually covered...she had changed her story..said I owed. Sorry.. You told me it was covered, and I have an invoice saying it was. I'm not paying you a dime.

Welcome to another chapter of "dancing with dealers".

Apparently there are GM-Chevy reps that are present in this forum who read what we say here. Let's see if they respond, telling us how great their dealerships are at handling us. If they do address your experience, you might want to reply to them.

[Beneficiall]

I'm not worried about it. She made an unfortunate mistake...however, it's one that will cost her or the dealership..not me. I have an invoice that says "covered under warranty...cost 0.00. I didn't word what I said clearly though. When I picked up car..invoice said I owed nothing. I was surprised..I said this is covered? she said yes. Called me a couple hours later. said it wasn't.

[javeo]

I'm currently going through the same situation..not a fun surprise..and I had to chase the threads in the pan..

I also used a M10 -1.50 bolt but I did not get a nylon washer so it's leaking (where did you get the right size nylon washer?..size?)
I ordered a replacement drain plug using Dorman 090-078 (ordered from NAPA# 7041049 for $2.49) which includes the plug gasket according to the picture. Not specified for Aveo I dont think, but the specs seem to match..will post an update once I install it..

It probably would have been easier to go with the nylon washer though

[Daox]

Any hardware store should have nylon washers. Copper works too.

[javeo]

Hi, thanks for the reply.