Hello everyone. I’m looking for a little input from the experienced Gem people. I have a 2002 two seater that recently developed a drive train noise at about 20mph. Kinda like a growling noise. My best guess is the differential but I don’t want to start taking things apart on a hunch. I jacked the front of the car up and rolled the tire forward and backwards a few inches by hand. Sounds like a lot of clicking inside the differential. Don’t know if this is normal or if the two issues are related. Any suggestions.
One additional thing I almost forgot to mention. The car has always had a pretty loud whine while driving which hasn’t changed with the new noise. I’ve never driven another Gem so I don’t know if the whine is normal. I’m not sure if the whine is the motor or the differential.
Jack up the car and check front wheel bearings for slop first.
I checked the wheel bearings in the same way you check them on a car. I didn’t feel anything unusual. No abnormal play. Wheel bearings on a car are typically more noisy on turns. Turns don’t seem to effect this problem.
You should pull the input shaft and check the bearings. If the small one lets go it will lunch the gearbox. If the car has 5000 miles it might be a good idea to install a new input shaft kit. Could reduce the whine also.
Thank you very much for your suggestions. I looked in the service manual and couldn’t find anything on a input shaft. I’m assuming this is the shaft in between the electric motor and the differential. Can this be serviced by just removing the Electric motor or do I have to remove the differential from the vehicle?
I removed the input shaft. Outer bearing seems fine but I’m not sure about the inner. The inner bearing really doesn’t feel bad but it’s not exceptionally smooth like the outer. I’m not sure if it’s the beginning of a problem or does it feel different because the outer is a sealed bearing and the inner isn’t. If it’s not too expensive I guess I will replace it since it’s already apart.
Where can I purchase a new input shaft or maybe just the bearings?
The bearings should have part numbers on them, just google the part number and you should be able to find them online. Or if you have a bearing/industrial store they will have them, Kamon industrial is one place.
I rebuild motors and gearboxes. How ever I’m not cheap, I also sell input shaft kits and EZ STEERs
Rodney
There is no visible number on the inner bearing. It probably has to be pressed off to see the number. The number is most likely on the inner race where it’s not visible. I hate to remove the bearing without having the replacement in hand. I’m not sure how I’m going to proceed at this point. Thank you for the suggestion.
How much is just the input shaft kit?
$190 including shipping
Do I reuse my old shaft with the kit?
No kit contains shaft, bearings, seal, and a new rubber bumper.
I have (1) 27 tooth left. Due to slow sales I no longer stock 21 tooth but will special order.with deposit. Takes 3 weeks.
Rodney
Good morning Rodney,
I wanted to thank you again for all of your help. I decided to put everything back together last night instead of replacing parts that didn’t appear to be bad. We drove it a couple of miles and the noise did not return. I will keep your contact information if I need anything in the future.
After reassembling with the same old parts the noise has mysteriously disappeared. I spoke with many people trying to educate myself on Gem vehicles. Several people recommend installing 90 weight gear oil in the differential in an attempt to quiet the gear noise. I am certainly no Gem expert but here are my thoughts on the gear oil.
The manual indicates that differential takes less than a quart of (30 weight) motor oil. The inner shaft bearing is located pretty high inside the unit. This means that it gets lubricated by the oil splashing around inside the unit. Many of the Gem people that I spoke to recommend installing a heavy weight (90) gear oil in an attempt to quiet down the gear noise. I’m thinking maybe this is why so many of them are experiencing a failure of that bearing. The 90 weight oil may be too thick to splash up and lubricate that bearing. I really don’t know for sure. Just my theory.
30 weight oil is installed to maximize range. Actually ball bearings are happy not to be submerged in oil. A bearing that has some wear, when submerged. has the possibility of the balls skidding and galling. That’s the reason it is bad practice to over fill transmissions and differentials. High speed precision bearings are often lubricated with airborne mist systems.
Most owners and service centers use SAE 90 weight differential lube because of the anti wear and extreme pressure characteristics built into the formula. It’s effect on noise is minor but it makes the owner feel good. In reality gear tooth loading in the Dana 12 series gearbox is not that great and it’s the reason you can getaway with 30 weight.
I know this is a older post but did the OP find out what the original grinding/clanking noise was?