Good advice. I did look in there to begin with but and didn’t see anything. I will take one more look… maybe I just didn’t notice it.
Ya know, for $10 I’ll order one just to eliminate that as an issue.
Hope to get video with sound today or tomorrow.
My guess is that since this happens at pretty much any speed, the only thing turning fast enough to make that sound is the motor and input shaft… Maybe the intermediate gear, but I doubt it… Let’s see how it all works out.
Have you ever see how the armature slides in and out as you accelerate/decelerate? It can move in and out as much as 3/4 of an inch.
The reason you need a bumper is when you hit the gas the armature slides into the coupler you don’t want the motor/armature Bottoming out and slamming into the motor coupler Every time you take your foot on and off the gas. I don’t know a Single DC motor in the Gem world that calls for the removal of the rubber Motor bumper. We all know what a Wore out input shaft and motor bumper sounds like. Quiet under acceleration but Noisy when coasting and deceleration
Actually I have dealt with hundreds of DC motors in my career but never one without a front bearing… Kinda makes sense for the rubber piece, I ordered one this morning but it is over a week away.
As I posted earlier, the manual actually says
“1 0313-00168 BUMPER, RESILIENT - DIFF TO MOTOR (FOR SHIPPING PURPOSES
ONLY, DISCARD BEFORE ASSEMBLY)”
It also doesn’t show any rubber piece in the assembly drawings… Hence my confusion about the rubber insert.
So I still need to show a video with sound… I still need to change the 30w oil for something a lot heavier and add some Motor Honey…
I’m working my way thru all the suggestions but it is taking time because of all the other parts of the float I am working on at the same time. I need a bigger shop! ha ha
Perhaps the rubber piece they are talking about in the instructions is some sort of Shipping Protection piece and NOT the Motor Bumper we
All know and love 
the ones Assembly required posted are installed deep into the Motor Coupler (the Female) side of the motor. In fact Gem and pretty much everyone else recommends you Replace the Motor bumper AND the bolts every time you R&R the motor. Most stock Gem motor bumpers are Smashed flat inside the motor coupler and you need a small screwdriver to pick them out. What motor did you install? Do D&D or R4F motors come with a bumper installed? It’s been so long since I played with a DC motor
ahhh… I figured it was “tribal knowledge”… ha ha… I put back the same motor that came out. The motor runs fine. When that bumper comes in I will pull the motor again. I don’t expect to drive it for several weeks other than to do that video…
It’s been so long since I played with any motors… ha ha… gotta love retirement! We loved them DC motors back in the day… running 2-5 400hp on a single line shaft for big printing presses was one of our specialties…
Finally got a video. I also received that bumper today. such a tiny thing it is… ha ha…
here is that video… finally got it out of the shop https://www.youtube.com/watch?v=JCVjm7No3uQ
So what was it ? After all…
That does have quite the howl to it.
Did you try the heavier oil in the gearbox?
How is it at parade speed?
If a person had TONS of free time, it might be interesting to pull the input shaft, clean it, and put some dychem on the teeth to see where/how it is contacting the intermediate gear.
Don’t know… I was hoping for advice… I haven’t changed anything yet…
Yeah… but I’m gonna confess to being lazy on that one… I will pull the motor and put that $10 piece of rubber in there and then change the gear oil from 30 to something like 85 or 90.
I’ll let you know what shakes from there.
Parade speed works fine but still has noise… just not as loud… livable because of the music.
Ok I stand corrected. No rubber bumper is gonna fix that. That is Gear whine like I have never heard before That’s a Serious Fail in my opinion, Stupid question. Are you sure your gearbox has oil in it
Yes, 16oz per the manual… but it is SAE 30. I’m putting 85 or 90 tomorrow.
I didn’t think the rubber bumper was going to fix it… but I take advice and try what it takes to fix it
Yea sorry bout that but until I could hear what your talking about that was my advice.
Ok here is my second round of Advice. Find a used transmission out of a Gem Truck. Find out the part number of that Gem transmission with the stock transmission gear raito of 14:1 and buy one. Then take the transmission that’s in your car now and throw it in the garbage.
With a replacement transmission you could have this sorted in a few hrs
That is not really an option. That transmission was quiet until I bought those gears from R4F and my mechanic friend put them in. I’ll try the heavy oil and motor honey and see if that takes it out.
I only have about 2000 ft on it after the gear change so we shall see how it shakes out…
I am really leaning towards this being a bad cut on the gears.
I was shocked that your vid shows you can be heard coming from a block away!!! What is it like riding in your car/train? It’s like those are straight cut quick change gears from a V-drive!! Your camera person cut off 3 seconds too soon. I wish it caught the rest of your neighbor’s “It makes alot of noise” comment.
I don’t think this sounds like bearing noise, but maybe? If so, use a stethoscope and listen to various parts of the case to isolate which one is loaded. That thing is ringing so loud that you may not be able to actually tell which part is the worst.
Thicker oil should help tone it down a bit. You can hear it bouncing off a little lash and going quiet for a microsecond when you were slowing down. If this were in a normal cruiser, it would be far from normal/acceptable for street use IMO. Your only save will be that this is going to spend it’s life at 3 mph and covered by background music. You may need to hot foot it back to your trailer after the parade.
Get it up on stands so you can run it in place. Run it up and down a couple times before you change oil. Then after. It might give you an idea if you did any good without getting it out on the road. Maybe drag your brake a bit to load the gears a bit.
@Old_Houseboater - Have you been following this thread? Any thoughts?
Talk to Bob and see what he has to say. Unfortunately, best case scenario has him sending you another set. This means you need to do the whole swap thing again. At least try a new input shaft. That is not too difficult to swap.
Spitballing
Perhaps the next move(after oil/additive) will be to rubber mount the gearbox. I’ve always wanted to see if one could slip a sheet of rubber in between the gearbox and clamp mount on the frame. Maybe something like a bunch of garden hose washers can be stuck in there.
well, swapping out gear oil can’t be that difficult and it will be an interesting test. I would say install the heaviest weight humanly possible he can’t hurt you in that I think heavy gear weight really penalizes high speed action but because you’re keeping your car at low speed I don’t see a heavyweight gear oil affecting your range.
OK… probably while you were typing this I was changing the gear oil and getting the damn Motor Honey all of the place… LOL So I put 80W-90 and Motor Honey in it and ran for a bit at slower speed jacked up… The rain stopped for a bit so I took it out and ran it on the driveway and it is still very loud. I’m pretty sure it’s not bearing noise. I put a stethoscope on the case at the outputs and near the input shaft and can’t pinpoint anything.
When changing the gears, the input shaft and its gear are one piece. The second gear in line has to be pressed on and the mechanic did that with a hydraulic press.
My next thought was to pull the half shafts and let the motor just run the box and see how much noise it makes from there.
What a pain this has been… I think I am up to about 1600-1800 feet of travel on these gears at this point. It’s about 500-600 ft to the end of the street and I did that twice… The rest is around my driveway.
See my answer to AssyRequired please.