Lubricant spec for Peerless Silent Trac transaxle

[vtonian]

My Murray 465603X92A with hydrostatic transaxle is doing the slowing down thing in drive, worse in reverse, and I'm thinking the fluid change procedure is going to be the fix.

I've seen all kinds of fluid replacement suggestions, from engine oil to ATF to hydro fluid, with results from great to horrible. On the internet, anything can be true/false.

In this 2019 post by Rocky4:

Peerless hydrostatic transaxle fluid replace

Hello All. Have a murray model 425612X99A tractor. Will only move slow or not at all forward or reverse. In all my research it leads me to believe the hydraulic fluid need to be changed. I have removed the transaxle from mower but do not see a way to drain and refill fluid. The...

www.lawnmowerforum.com

Tom3 mentioned the lubricant for a Peerless 2000 transaxle in a Murray 425612X99A was Mobile 424. My Silent Trac 2000-02A transaxle looks like it might be close to identical to the one shown in the drive assembly parts diagram for Rocky4's, so I'm guessing/hoping it's close enough, it's the only specific lubricant I've found.

My first question is, is that a legit Peerless lubricant spec? If so, and if lubricant breakdown is the potential issue, seems like using it or a valid comp would be the best idea:

PdsDetailsPage

Mobilfluid™ 424 is an extra high performance multipurpose tractor lubricant engineered to meet or exceed transmission and hydraulic fluid requirements.

www.mobil.com

OTOH, if internal wear is the most likely issue, maybe the potentially higher viscosity of a synthetic oil is what's giving some people good results with that, and just replacing it with the same stuff won't make much difference.
Rocky4 used engine oil and trashed his. My theory is, like Tom3 mentioned later in that post, maybe the engine oil wasn't compatible (additives, etc).

Tom3, if you're around, can reveal where you found that Mobil spec?

Tom3 or anyone, do you have any other insights into whether synthetic engine oil is bad for these particular models of transaxles (Peerless 2000 series)?

Thanks much for any help, enjoy the grass growing season!

Matthew

 

[Bange]

My friend, the oil specified by the manufacturer will always be the best oil, as he has tested and approved the use.

 

[vtonian]

Thank you for the reply, Bange. I don't see the 2000 hydrostatic series listed on that chart, did I miss it?

I think they're designated as 'VST', Variable Speed Transmission when Peerless refers to them at all, and AFAIK, they recommend tossing them, not servicing them, when they don't perform properly anymore. From what I believe is the same Technicians Handbook your chart comes from:

"SECTION 11. VST TROUBLESHOOTING
The information on the following pages has been provided to help understand the internal operation of the VST. Do not use this information to attempt any internal repairs. Tecumseh's current policy on hydrostatic transaxles that have internal failures is to replace the complete unit"

Changing the oil, AFAIK, is a hack that has worked well for some, like this guy:

Murray Riding Mower / Peerless 205-024C Transaxle Issue Solved

How to solve issues with Murray Peerless 205-024C Transaxle. Slow in forward and reverse. How to change hydrostatic fluid oil.

peerless205-024c.blogspot.com

but that isn't a 2000 series.

I haven't been able to find anyone else that's made as confident a statement as Tom3 about what is supposed to go in a 2000 series transaxle.

Thanks again for your reply. If I've missed something there, please pardon my oversight, I'm new at this and any clarification you might offer would be appreciated.

 

[Craftsman Garage]

hello

 

[Bange]

In fact, there is little information about VST, where the manufacturer recommends a complete replacement, if the problem is not solved by the few tests indicated in the manual.
The exact reason for this is unknown, but I can quote some such as the decision not to manufacture anymore, difficulty in obtaining internal parts from third parties, failure of the project pointed out by dissatisfied users ...
Although it is a great comfort when in normal operation, in case of defect it is a complete disappointment and high cost for users.
However, I again affirm that the best oil is the one indicated by the manufacturer ... if your problem is only oil, which in this type of transmission are 2 (ATF and SAE 90 or 80W90), replace exactly the same.
I am also new to this area of lawn mowers and I am reading a lot about it, but I have a reasonable experience in general mechanics and a little more in automotive.
I have a Murray 42L18G608A, Peerless MST-206-565, B&S 31P777, bought used and badly treated, which I am gradually recovering ... my problem is the lack of parts or its high cost ...

 

[mitchstein443]

Just use ATF, dextron or mercron is best for it. In all seriousness, when it comes to hydrolics, ATF, motor oil, powersteering fluid, brake fluid will all work.
Powersteering fluid will just work as hydro fluid, ATF will superclean the system, swell up any worn seals and recondition them. Brake fluid will clean the system but not as well atf, and will super condition the seals.. All the fluids can withstand the temps in a garden transmission.

There really is no down side to using them and my first choice is usually ATF Merc.. as it has the highest cleaning power and 2nd highest durability (about 8 years before it starts to breakdown)..

 

[vtonian]

Thanks, Mitchstein. In lieu of a specific manufacturer spec, ATF sounds like a plan. I was reading about how engine oil is formulated to deal with the byproducts of internal combustion, synthetics are prone to leakage in older/worn seals, and other formulations/additives in other fluids may not be suitable, so ATF in an AT seems like about as good a choice as possible.