Transmission drain plug B 2920

Tractorrr · Jan 16, 2014

I was replacing the transmission fluid that was lost when I changed the suction filter and overfilled it a little. I took the drain plug off to drain some of the fluid to get it back into normal range. When I hand tightened the drain plug back on it gets to a certain tightness but then loosens back up after that not allowing it to go back on right. It is able to go back on fairly tight but this is pretty frustrating as I'm not sure what would be causing this. Maybe the threads are stripped. This is the first time I have taken this plug off on a fairly new B2920. Any advice on this would be appreciated. Maybe I need to try a new drain plug? Anyone ever had something like this happen? Maybe I should leave it the way it is as it doesn't seem to be dripping once I get it back on the best I can. This is the drain plug by the mid PTO.

s219 · Jan 16, 2014

Sounds stripped to me. Could try wrapping the plug in teflon pipe tape to gain a little more bite before it gives up.

Katahdin · Jan 16, 2014

A coworker of mine just did the same thing to his B. The pan was aluminum so its easy to over torque and strip. The dealer retapped the threads and put in a larger plug.

sixdogs · Jan 17, 2014

Sometimes you can add an extra washer and that will work by keeping the stripped portion of the bolt away from the threads.

Tractorrr · Jan 17, 2014

Thanks for the replies, gives me some ideas to work with. Just wish this would have gone smoothly. Glad to know this has happened before though.

Tractorrr · Jan 17, 2014

Got it wrapped in thread tape. Am able to tighten it more so I will probably just leave it alone now. Thanks.

madamos · Jan 17, 2014

I recommend a proper repair, either drill and tap oversize or a thread repair like a Helicoil or Timesert. If the plug is just wedged using Teflon tape it could vibrate loose and even drop out unexpectedly which would at the very least be a big mess and at worst if not detected, result in equipment damage.

Paul

s219 · Jan 17, 2014

Depends on how tight he was able to get it. Plenty of threaded pipe connections in hydraulics use some sort of teflon -- usually dope, but can be tape if it is carefully wrapped and applied. We don't worry about them backing out. If it was me, I'd really try to assess it before deciding if re-tapping was needed.

madamos · Jan 17, 2014

I am ok with Teflon tape/paste when used for tapered pipe threads that they are intended to be used with.

My concern is that if the threads are physically damaged and the bolt(plug) won't take the required torque that is a sign that it just "feels" tighter and as the tape cold flows it will soon loosen.

I am a maintenance instructor at a nuclear power plant and correct bolt tensioning is one of the classes that I teach.

Paul

Tractorrr · Jan 18, 2014

I agree with getting the proper fix. Wrapping the bolt in thread tape may only be a temporary fix for now.

sixdogs · Jan 18, 2014

Teflon tape would concern me but I do not have sufficient experience with tape in an oil pan application. I like the idea of just adding an extra copper washer to see if you can avoid the stripped part of the problem. Over the years I have seen this used many times with success.

Tractorrr · Jan 18, 2014

I think I will try the washer trick or heli fix

sixdogs · Jan 18, 2014

Tractorrr said:
I think I will try the washer trick or heli fix

Learn what the torque spec is just for chuckles and approach it slowly as you tighten.

EDIT

Heli fix would extend inside beyond the lip of the pan and probably prevent all the oil from draining out during a change. You only have a couple of realistic options. The hard answer is to retread to a larger size. The easy answer is to try the added washer or if the Teflon tape thing will work I guess that's an option.

Gary Fowler · Jan 18, 2014

Snug is usually good enough for these plugs in aluminum pans. It doesn't take a lot of torque to strip the threads. Lucky or not, at my age, over-torqueing is not a usual happening.

ackerrj · Jan 21, 2014

Gary Fowler said:
Snug is usually good enough for these plugs in aluminum pans. It doesn't take a lot of torque to strip the threads. Lucky or not, at my age, over-torqueing is not a usual happening.

The dealer here recommended just slightly beyond hand tight.... Snug is a good way to put it.

sixdogs · Jan 21, 2014

Have you put the plug back in yet?

srs · Jan 21, 2014

Tractorrr, I copied my response to the thread under Kubota Owning-Operating dated 1-10-2009 B3030 150 HR SERVICE

Don't make the mistake I made at 48 hours when I over tightened the drain plug bolts on the HST transmission and stripped the threads on one side. I ended up going to ++ TIME-SERT Threaded inserts for stripped threads, threaded inserts, thread repair stripped sparkplug's, Ford sparkplug blowouts, threaded inserts threaded, repair stripped threads, stripped threads, inserts threaded inserts, Ford spark plug repair, for a thread repair kit and fixed it myself. Lost some sleep for a few days though. Transmission case is made of aluminum which royally sucks. Made me sick when the bolt just started spinning inside the trans case. DON'T OVERTIGHTEN!!!!!

Tractorrr · Jan 23, 2014

Sixdogs, I will try to get a new transmission drain plug from Kubota to see if it will work. A friend thought the threads were stripped on the plug but that the threads in the pan looked ok.

sixdogs · Jan 24, 2014

Tractorrr said:
Sixdogs, I will try to get a new transmission drain plug from Kubota to see if it will work. A friend thought the threads were stripped on the plug but that the threads in the pan looked ok.

Use a torque wrench the first time so you can feel how tight "tight" is but stop a half lb short if anything feels funny. Don't forget the gasket. Might be copper, might be rubber and might be copper wrapped in rubber. Sounds like you will come out OK on this. I always wondered if the pan metal was harder than the pan plug.