My Marathon's rear end has a noise

[BJustice]

I have an electric ’98, 36V, EZGO Marathon that is stock (not lifted or anything special). A growling has developed rather quickly in my rear end. The oil level is correct. I have lifted each wheel individually and spun them and raised the entire rear end and spun the wheels. None of these actions reproduced the noise. The noise only occurs when the motor is running. I replaced the motor with a backup motor and the noise is exactly the same. I feel this eliminates the motor being the source of the noise. The pitch of the noise increases rapidly with the speed of the motor. This leads me to believe that the source of the noise is either a bearing or gear that is turning rapidly (ie in the input shaft section). I am guessing that a bearing or gear in the differential area would not increase in pitch as rapidly as this is doing. (Please correct me if I am wrong about this assumption) I cannot pinpoint the location or source of the noise. I tried the old school method of putting my ear to a pipe and listening to each part of the rear end, but no luck.

From your experience, do you think I am on the right track? What should I look for or try? Is this a typical failure area for this model cart and if so, which parts (gears or bearing or both) would make a growling noise?

Thanks for any direction you can give me!

[ab46501]

The input shaft bearing can be changed fairly easily. You can get both input bearings for less than $15 off the internet. Try that first and see if it helps.

I would check in see if the differential cover was dented. If you climbed over something and it hit the cover it could be pushed in against the main ring gear. Also if you have been through deep water it is possible that the axle seals failed and water has gotten in the differential.

When was the last time the fluid was changed?

[BJustice]

The fluid has not been changed since I have owned the cart (5yrs). I will do this. Should I use the standard 90 weight or other?

There are no dents and it is kept indoors and has not been through any water.

Can you change the input shaft bearing on the cart or do you have to drop the rear end? Is is typically the bearing and not the gears?

Thxs!

[ab46501]

I use 75w-90 Royal Purple in mine. You can check the manual but any good gear oil should be fine. You can go heavier weight oil if you like. That would help the noise some.

If you do not have any damage to the cover and have not had water problems then my guess would be the bearings but anything is possible.

To change the input shaft bearings you will need to remove the motor. There is a snap ring that will need to be removed and then the shaft with the two bearings on it should slide out with a little effort. There is a rubber O-ring that will come out to so be sure and don't losse it. You should be able to do this without dropping the axle.

I actually just spent yesterday replacing all the bearings in my rear end. I have had the high pitched whine. I did however hit something and dent the pan but visual inspection of the gears appeared to be normal and it sure sounds like a bearing whine to me. I replaced the input shaft bearings already and that did help some so I think I am on the right track. I have not got the rear back on the cart yet so I can't confirm if my issue is fixed. I hope to do that this week.

[yurtle]

One trick for isolating the source of a noise is to have someone drive the buggy, while you CAREFULLY listen. If you take off the seat back, you can probably place a wooden stick against various parts and listen. Culprits could be bearings in the motor, axle, differential, or maybe even brakes.

Owner's, Parts, and Service Manuals:
http://www.buggiesgonewild.com/elect...g-manuals.html

Dana Axle:
http://www.buggiesgonewild.com/attac...5-28148g01.pdf

I tore my '98 rear-end apart and replaced all seals and bearings.

[pggroves]

Pardon the interruption but I'm confused....(<---easier to do these days)

OP indicates a '98 and a Marathon. That doesn't compute. If it's an '88 and a Marathon, OK, but then the rear end could be different than a '98. EZGO had some changes in the ?mid to late 80's? on the rear end vendors as well as differing input configurations. (e.g. splined vs armature gear).

Probably a typo but just trying to make sure we know what the OP has in order to accurately assist in troubleshooiting.

Good luck.

[BJustice]

Sorry, yes '88.

Can you remove the bearings from the input gear and the intermediate gear w/o removing the output gear / differential assembly?

I am having problems getting the nuts off of my axle to check those bearings. They have never been off since the cart was born and cannot get them to budge. Any suggestions?

Thanks for you help!

[ab46501]

Originally Posted by BJustice

Sorry, yes '88.

Can you remove the bearings from the input gear and the intermediate gear w/o removing the output gear / differential assembly?

I am having problems getting the nuts off of my axle to check those bearings. They have never been off since the cart was born and cannot get them to budge. Any suggestions?

Thanks for you help!

The input gear will slide out with the bearings on it. Very easy to change.

You will have to remove the freeze plugs (and install new ones) to get the intermediate gear out. I have never done it without the whole thing apart but I think it would come out.

Are you talking about removing the whole axle from the cart or are you saying you cant get the nuts off the differential pan? Either way soaking in some good penetrating oil will help.

[BJustice]

I cannot get the nut off of the Axle to take by break hub off. I wanted to check the axle bearings as well.

[ab46501]

Originally Posted by BJustice

I cannot get the nut off of the Axle to take by break hub off. I wanted to check the axle bearings as well.

Ah OK..... so you are talking about the castle nut. There is a pin in it. Make sure it has been removed. The pin could have broke off an not be easily visible.

If the pin is out I would clean the threads with a wire brush and soak it with oil for a day or two.