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Craftsman GT5000 with 331-3000 transaxle problems

19074 Views 11 Replies 5 Participants Last post by  emptx
Hello all,

I have a used Craftsman GT5000 mower that I purchased back in early 2008. I used it through 2008 and began to notice the transaxle was running progressively slower in reverse towards the end of the mowing season. The transaxle also began to make more of a whining sound when moving the motion lever forwards or backwards. I rarely used the mower last winter and early this spring, and only recently had time to take a serious look at this problem.

I took a look around on MTF and found a "sticky" here. Many thanks to member Mowerharald for this thread and his willingness to help via e-mail. I did the initial drain and refill using 20W-50 oil. Below is a photo of what the old fluid looked like...

I purged the system, rode it around the house once, then topped off the fluid. A few days later, I had the opportunity to mow. Initially, the transaxle did great and seemed to be much more responsive with the new fluid. However, after about 20 to 30 minutes of mowing in some warm weather, the transaxle began to hesitate and was making quite a loud whining sound when going forward...reverse eventually stopped working. I put my hand on the bottom of the transaxle cover and it was very warm. I figured there was still some bad fluid leftover, so I drained, refilled and purged the system a few days later. I did not take a picture of the fluid this time, but it did not look much better than the first drain. I am still experiencing the same results. I can only mow about 20 to 30 minutes, then the transaxle whining and hesitation sets in. The bottom cover on the transaxle is again very warm to almost hot. To add a little background, the cooling fan on top of the transaxle is clean and turning. The cooling fins on the transaxle are clean. I did put all new belts (drive and mow) on the mower earlier this year.

I'm thinking the fluid is getting too hot, but I'm not sure exactly why. I will gladly do another drain and refill, but I am wondering if anyone else has had a similar problem with this transaxle.


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Looks like water in the oil.. Do you wash the tractor? does it live outside? any time I have ever seen oil like that, it was contaminated with water. It would be interesting to leave the old oil sit for a week and see if anything separates out of it.
I think they have a filter inside. Might have to change that ? If the oil looks like that the filter can't be looking to good. Might be pluged up ?

I share your thoughts about water in the oil. I can't say if the previous owner ever washed or left it outside, but I would not doubt it. As for me, I did power wash it one time not too long after I bought it. Since then, I have read where that is not such a good thing to do, so I stopped. It does get an occasional hand wash, but I'm careful not to deliberately spray water near the transaxle.

Small Fry:

I do have a parts diagram for this transaxle and until now, did not look close enough to realize that there is indeed a filter located just inside the bottom cover. Thanks.

I hope I don't have to drop the bottom cover, but if that is what it takes to get my mower running again...

Thank you both for the replies.

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Seems I read a thread about changing the filter, let me see if I can find it.
Here is a little info, but not what I was looking for. One guy changed his and when he removed that bottom plate the filter fell out. He said he had to pull the trans and flip it up side down to put the filter back in.

I would call hydro-gear and ask them so I new for sure.

I have the same tractor but... so far so good.
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I would drop the pan and change the filter Hydro-gear pn 70538 filter kit around $25 at mower parts stores(Parts Tree, M&D, order tree, etc) good price here. Sears wants over $50.

Is your vent plugged? That could lead to the build up of condensation in your transaxle.
I would replace the oil with synthetic when you refill it. That should make it run cooler and slow down the wear.
Small Fry:

Thanks for the link and contact information. I will call or e-mail the folks. I sure hope I don't have to remove the transaxle from the mower.

Glenn M:

Thank you for the link. The vent cap is clear.


I do plan on going with synthetic oil once I get this solved. Any particular brand you could recommend?

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I use Mobil 1 in everything.
SockPuppet: Thanks.

I had a chance to talk to one of the technicians at and they thought I may have some internal problems with the transmission. I don't remember the exact parts he named, but it was suggested that I remove the transaxle from the mower, then take a careful look at the inside gears. I'll have to tackle this a bit later. Thanks to all for your suggestions.

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