t300 slow/jerky on one side

So I just picked up a 2000 t300 with 4100hrs from a friend , who said it was slow/jerky on the left side, so they bought a new machine. they are not mechanics so the dealer has done all their work. it backed off the trailer ok, the right side drive motor has been replaced with a longshaft one awhile ago.
I am thinking of pulling the case drain,seeing if there's any metal in it, and possibly pulling the drive motor and checking if the brake piston seal has been bypassing. I'm wondering if the brake isn't unloading completely if that could cause the issue? might even swap sides and see if it follows if I don't find any other issues. Anything else to check out?
It also seems to be leaking oil around the back somewhere. almost looks like the oil pan is sitting on the bottom plate like the mounts are done?

Guess I'll just have to dig into it and hope I figure it out.

Can you better describe "slow and jerky", just what is the motor doing on that side? Does it hold neutral properly? Does it do the same thing in forward and reverse?

All I know is those t300 were notorious for drive motor problems. But start off by draining the drive motor oil. Maybe even pop the cover off.

Have you checked the steering linkage?

Well I got a minute to mess with it today. the left side has a little slack in the linkage because the aluminum piece is loose on the shaft coming out of the pump. other than that, it seems to work just fine, I was running it back and forth and doing donuts for awhile and it didn't hiccup at all. he did say it got worse the warmer it got. At this point I'll probably check the case drain, tighten the linkage up, and run it awhile til it starts acting up on me.

CM1995 said:

Have you checked the steering linkage?

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TIredoldparts said:

Well I got a minute to mess with it today. the left side has a little slack in the linkage because the aluminum piece is loose on the shaft coming out of the pump. other than that, it seems to work just fine, I was running it back and forth and doing donuts for awhile and it didn't hiccup at all. he did say it got worse the warmer it got. At this point I'll probably check the case drain, tighten the linkage up, and run it awhile til it starts acting up on me.

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That's kinda where I was headed. It's a common problem on Bobcat machines that used the one piece aluminum pintle arms on the pump control shafts when the clamping bolt for the pintle arm gets loose and allows it to move around on the shaft, they get wonky when that happens, damn near impossible to keep one in neutral when they get loose.

If it gets worse once the unit gets hot it is probably internal to the drive motor. As stated it is pretty common. I would run it and get it good and hot and see if you can duplicate the issue first. Swapping drive motors is a lot of work. Drive sprocket and track rail is good ??

You can cap brake release lines one at a time and monitor charge pressure to check brakes with out having to remove motor. I’ve seen where opposite side fails and dumps all charge pressure to cause brakes to drag on remaining side.

well I've been gone and hadn't had a chance to check it out. needed to move a stack of roofing metal yesterday, and it was running while I was positioning the truck to unload it. when I got back into it, there was a high pitched squeal coming from the left, and it was dragging, indicating the brake was not releasing completely. so looks like the brake seal is bypassing when it warms up.
In the process of cleaning all the dirt from around it to remove. what a mess. IF I didn't have it inside I would have pressure washed it. I'm going to pull the cover as see what the brake stuff looks like. I'll probably put new seals in the brake piston and and cover plate and run it though unless I find a big mess.

Well If anyone cares, I was able to put new piston seals in it for the brake, and the outer gasket and its now working great. just need to take out the slack in the left actuator arm. then ran it low on diesel in the yard and it quit. had to put 5 gal in and bleed the filter.