Pds when coasting in tow mode makes a whine noise

[TomClevenger]

I have a 01 pds and I have the toe switch on the dash so when I'm going down hills I can flip it to coast so I was going down a large hill I flipped it it was going fine the few times I did it but the about to the bottom of the hill going about 35 it started make in a loud whining noise from the motor or rear end I stopped took off did it for a second then it stopped and was fine what could it be ?

[scottyb]

Warning ......I have never done what you describe but I can tell you that the cart has regen and possibly roll-away protection functions which may be harmed by what you are doing unless you have an aftermarket control which you didn't say? Anyway the stock motor and most aftermarket motors cannot take the high RPMS you describe if it is not a motor bearing it may just be the motor getting ready to come apart.
Lets wait to get some more specs on your 35mph golf cart and hear from our experts on this ......

[JohnnieB]

I'm no expert, but at 35MPH on stock height tires, you are spinning the motor at about 8,500RPM, which is about twice what the controller limits the motor RPM to in Freedom Mode. If properly lubricated, the differential can probably take that speed, but I doubt the motor liked it very well, especially if the motor bearings and lube are original.

Since the whine went away, my guess is that it was an overheated motor bearing, which has now been compromised and needs to be replaced.

If you want to freewheel with a PDS cart, upgrade to a controller that does away with regenerative braking and get a motor that can take the RPM.
Also, install brakes that will stop a half ton mass at that speed.

[TomClevenger]

It was in tow mode so I thought it would disengage the motor but apparently not so the motor stays engaged the whole time no problems with it any more so hopefully its good now gonna change fluid in rear end and go from there

[JohnnieB]

It is a direct drive system mechanically. Turning the controller ON or OFF is all the Run/Tow switch does.

Personally, I would have the motor bearing replaced also.

[TomClevenger]

Ok thanks

[yurtle]

I'm still tryin' to break the 40 mph barrier.

AMD 36-volt (6.1-hp@5330 rpm) HIGH SPEED series motor, fed 500 amps and 48 volts.

But I don't cry when I succeed at doing destructive testing. I know what I'm gettin' into.