eMax 22 HST Pulsating noise coming from the transmission

tractornewbe · Dec 30, 2015

After the 50 hr HST transmission service (used Mahindra fluid and filter) at about 65 hrs I started noticing a slowly pulsating "scraping" noise coming from the transmission, only when the oil got good and warm. The noise varies with engine speed but does not change whether in 2 or 4 wheel drive, in neutral or low or high range. There is no noticeable change in performance but it's something I definitely did not hear before. It seems to me that it's slowly getting louder with time. I finally notified the dealer and had them look at it as I was concerned it might be a bearing or something serious. They claimed it had to do with a hose or valve vibrating against something when oil is warm and replaced both a hose and a "valve" on the HST. When I got a chance to test it out after a good warm-up, the noise still shows up. Dealer claims it's not anything to worry about. I have not found anybody else claiming the same problem so either no one notices it or it truly is not an issue. I am considering replacing the Mahindra HST fluid with another high quality fluid from Shell (Spirax?) to see if that clears up the problem.

Has anyone had this same problem in their eMax?

Rdr202 · Dec 31, 2015

Has anyone had this same problem in their eMax?[/QUOTE]

I picked up supplies to do the 50 service yesterday , I also bought the Mahindra branded hydro fluid. I will not be doing service until end of next month but I'll let you know if I get any new sounds.

oldpilgrim · Dec 31, 2015

I can't imagine the brand of fluid would make a difference as long as it meets specs.

You say it makes the sound in neutral as well? Does it change when sitting in neutral and working the loader or 3pt? To me that would indicate a pump problem.

davesl708 · Dec 31, 2015

Are you sure the fluid level is up to the full mark?

Mattt2778 · Dec 31, 2015

Just curious, did you do the 50hr service? Did you clean the suction screen? Change all the filters?

tractornewbe · Jan 7, 2016

I didn't notice any difference after hearing the noise then operating the loader but I'll pay closer attention to it next time. I did the service myself using Mahindra fluids and filter. I did NOT check the suction screen because at the time I couldn't figure out where it was. Initially the dealer told me not to bother with it. The tractor went in for a check after my service and I mentioned I didn't check the screen so if they thought that was a problem I told them I would pay for them to do it. They didn't charge me so they didn't do it either. I DO intend to clean it myself anyway at 100 hrs and I'll have to buy new hst fluid again! As far as fluid levels, I made a little dip stick marked where the factory level was before draining and filled it back to the same level. With a backhoe on its next to impossible to see the level on the sight glass. And no, I didn't accidentally drop a piece of the dipstick into the transmission!

Jabonee · Jan 8, 2016

You may want to inspect the suction screen. If there is a bearing or other HST component failing the evidence will be on the screen. :thumbsup:

mcfarmall · Jan 11, 2016

I've seen industrial power units that make a "pulsating" noise as the system builds pressure then dumps across a relief valve. Maybe there is a relieve valve in the system that is dumping periodically, perhaps there is an air pocket in the system somewhere that was created when you drained and refilled the system and is causing the noise. Just some ideas.

tractornewbe · Jan 18, 2016

Thanks to all for the suggestions. I have yet to drain the HST again and tackle that suction screen to see what's collected in there. I hope it is just a relief valve or some air and not pieces of the bearing coming apart. I'll let you know when I've completed that job.

lanschuetz · May 14, 2019

Very old thread I realize, but it is the closest to what is up with my eMax 22 HST. Quick bit of history: weather has been really wet here so mowing every 3 days with MMM. Having to often creep along to not bog down the tractor. A few days ago, while mowing, the belt broke. I'm at 230 hours, so not terribly surprising, but probably related to lots of mowing. Mower blades are OK, but definitely over-due for some sharpening.

Got a new belt and installed with help (if you can hold back the pulley and install the belt at the same time you are way healthier than I am). Bit of squealing from some idler pulleys, which have no grease fittings. Gave them a shot of WD-40 on top and bottom, which helped. One still wants to make a noise when turning off the PTO, but I think as the new belt stretches into place it will be fine.

But now - and actually a bit before the belt broke - I have a new noise. When mowing downhill or with minimal cutting, there is a "thwacka -thwacka - thwacka" noise from the PTO case. It's related to the mower deck as it does not make this noise without the mower deck attached, nor does it make this noise with the drive shaft attached to the mower deck with no belt attached. The latter was done as an experiment before installing the new belt to make sure there were no PTO nor drive shaft issues. It was so quiet in this mode that I had to get someone to verify that the drive shaft and mower deck gear box were turning.

Interestingly, when the mower is under some load (e.g. cutting up hill or through heavier grass) the noise goes away completely. It's not just masked - it's really gone.

Fluid levels are spot on and the fluid is clear and clean. Fluid was changed at 50 hours per instructions but not since as next interval is 500 hours.

I'm at a loss since this is only an issue with the MMM running but not under load. Maybe it's supposed to sound like that. There's no vibration, no loss of power, or any other
indicator of an issue. Help?