2011 E6 regen Growl

It’s runs good but as soon as I let up it has a growl. Touch the throttle and it quits.
Up on jacks, wheels off and at throttle it starts a vibration. Slightly touch the brake and it quiets down. Not sure where to start?
@Inwo @Old_Houseboater

resilient bumper maybe?

  1. Turn off regen

2 replace rubber bumper in motor coupling

3 Replace input shaft kit

4 If you have a long 5hp motor replace spline coupling

In a message dated 5/28/2020 9:28:00 PM Eastern Standard Time, electricforum@discoursemail.com writes:

Pulled the bumper out of the 7hp and it wasn’t bad. Unloaded on a jack, wheels off accelerate to full throttle and feel the vibration. Lightly step on the brake and the vibration stops. Possible input shaft bearings? You have a shaft kit?

Updated history: Also, the controller was rebuilt by FS and it seems the regen is off. Going down hill it hit 32mph with foot off pedals. Growling was hit and miss at different coasting speeds. Bought is from a guy that gave up on codes 81, 82 and brake light intermittently lighting. He replaced the magnet and tach sensor. Tach sensor was melted. I tapped the bushing flush and replaced the tach sensor . No more codes and when brought to top speed then backed off the accelerator the growl started showing up.

Update: Found the input shaft motor side bearing was bad. Splines were slightly worn but not requiring replacement. I replaced both Bearings.
Changing the oil and will test it later today

Update: Tested it and found it still was growling! Local guy said check the motor. I swapped out the GE 7hp motor with a D & D motor I had. It stopped Growling!
Found the Armature bearing was toast! Taking it to get new bearings. Would also replace the Motor Coupler but not able to find the part number and where to find one.
Any ideas?

I have a few. Do you know how to change one out? If you don’t do it right it’ll shake like a dog shittin peach seeds.

My success rate is about 50%

$108 including shipping. No returns

Now that’s a Visual! Thanks Rodney.
I have to get this out of the local shop to see what they have done 1st.

Input shaft test
Old Shaft, new bearings
Old GE motor rebuilt but same coupler
Old shaft play measured at the small bearing 177 thousandths
New shaft play measured at the small bearing 140 thousandths

American motor 3GU-4002 motor used 2014 model low hours
New shaft play measured at the small bearing 80 thousandths
Old shaft play measured at the small bearing 107 thousands

GE motor Growls with new bumper and old on regen
American motor very quite.

Any Sugestion? @Old_Houseboater, @Inwo, @grantwest, @LithiumGods, @MikeKC

If motor coupling splines are pointy and shaft is not worn change coupling. Is motor bearing ok. I assume you have new input shaft.

Why are you using regen? try turning it off.

When you say American motor do you mean AMD? (My favorite motor after my modifications)

Yes, new bearings on old shaft. Splines look good, and yes AMD Motor.

What exactly are you measuring? Is it a growl or vibration? Did you try a new input shaft kit? Can you post a closeup of the splines on the shaft and the coupling? If at least one of them doesn’t have some flat left on the top of the spline you have potential regen vibration. Is the snap ring seated properly?

Yes to all the above. The AMD motor will do 26mph and hit the governor and regen is fine no regen growl using the old shaft, the GE motor does 30 mph then hits the governor and is when the regen growl starts. Did not install the new shaft yet.

When the shaft splines are worn and the motor coupling splines are worn is when you start to get noise. Changing one or the other usually makes it go away for a few years. I would venture to guess the spline in the AMD is in better shape. Suggest you install the new input shaft and report.

Ge coupler
Looks ok to me

GE old motor with cleaned coupler and shaft.
New shaft has at the small bearing end .250 inch play. The old shaft had 1/3" play.
Measured this fully inserted.

That is worn out. Blow it up and look at the bottom of the spline in the unworn area notice the unworn portion that has flatted tips. if the shaft is worn the same way you have a real problem. That is as worn as I’ve EVER seen. You might consider changing out the motor. thats a 7hp fan cooled and changing out the coupling on a fan cooled is probably expensive. I have never done it on a fan cooled. Might be interesting. I would like to see a picture of the shaft spline.

I have serviced RFF motors available if your interested.

I just installed the new shaft and going to test the old GE now.