# Jerking in fwd and rev does not drive **URL:** \ **Category:** GEM Forum\ **Created:** [October 19, 2023, 12:26am UTC](https://community.electricforum.com/t/jerking-in-fwd-and-rev-does-not-drive/27068 "2023-10-19T00:26:01Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![312Bear](https://avatars.discourse-cdn.com/v4/letter/3/b9e5f3/32.png) [@312Bear](https://community.electricforum.com/u/312Bear)\ **Post date:** [October 19, 2023, 11:04pm UTC](https://community.electricforum.com/t/jerking-in-fwd-and-rev-does-not-drive/27068/22 "2023-10-19T23:04:44Z")
Picture of some of the front gearbox fluid. Looks nasty. No large chunks of metal. No where closer to figuring this thing out. 🫤 ![image](https://canada1.discourse-cdn.com/flex030/uploads/electricforum/original/2X/8/8153fab20d56c6f828938927f759b275f9dd10f5.jpeg) [On ground will not move.](https://youtube.com/shorts/HRCDwEZeOZE?feature=share) [With wheels of ground goes 25 MPH](https://youtube.com/shorts/e7eaf-GHCMQ?feature=share) ---
**Author:** ![Inwo](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.electricforum.com/inwo/32/1067_2.png) [@Inwo](https://community.electricforum.com/u/Inwo)\ **Post date:** [October 20, 2023, 12:06am UTC](https://community.electricforum.com/t/jerking-in-fwd-and-rev-does-not-drive/27068/23 "2023-10-20T00:06:27Z")
Check for shorts first. Eliminate the easy stuff. @djgabriel2004 ---
**Author:** ![AssyRequired](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.electricforum.com/assyrequired/32/7621_2.png) [@AssyRequired](https://community.electricforum.com/u/AssyRequired)\ **Post date:** [October 20, 2023, 1:07am UTC](https://community.electricforum.com/t/jerking-in-fwd-and-rev-does-not-drive/27068/24 "2023-10-20T01:07:12Z")
I don’t think I would have jumped to the gearbox being an issue. Looks like gear oil to me. Hold it up to the camera a little closer and I might be able to smell it. Try and stay focused. You have missed a few suggestions that might point to a clue. This makes some of us feel a little unwanted and will wander off to other projects. Let’s get some background - What is the history on this car? - How long have you had this car? - Did you buy it this way? (non-working) (depending on how you answer the above questions…) - When was the last time it was working? - Was there an event that might hint at a possible cause to this issue? ---
**Author:** ![312Bear](https://avatars.discourse-cdn.com/v4/letter/3/b9e5f3/32.png) [@312Bear](https://community.electricforum.com/u/312Bear)\ **Post date:** [October 20, 2023, 1:33am UTC](https://community.electricforum.com/t/jerking-in-fwd-and-rev-does-not-drive/27068/25 "2023-10-20T01:33:56Z")
Fair enough, cart is from a guy in my neighborhood. He has owned it for over 2 years, he installed new agm batteries himself. 48V cart. Says he was getting upwards of 30 miles after new batts. Then one day went to use it and it would not move. Just jerks in either forward or reverse. I removed all phase wires from the motor like @Inwo suggested. Result = no open circuit code. Unplugging speed sensor made no difference. ---
**Author:** ![djgabriel2004](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.electricforum.com/djgabriel2004/32/12304_2.png) [@djgabriel2004](https://community.electricforum.com/u/djgabriel2004)\ **Post date:** [October 20, 2023, 1:35am UTC](https://community.electricforum.com/t/jerking-in-fwd-and-rev-does-not-drive/27068/26 "2023-10-20T01:35:13Z")
I’ve got the same problem before, Dealer told me batteries were low (not possible because I work with batteries and gems every day and I knew voltsge was ok) Traced every wire, they were ok , replaced contactor, nothing, speed controller, nothing replaced the motor, boom worked. Left the old motor in my garage because I like to hoard unnecessary stuff, FF a few months a client brought me a car with motor temp sensor issues, decided to put this old motor that has been sitting and boom it worked like a champ, told him to bring it back if fails, its been a year and I haven’t heard back from him Conclusion, I have no idea what could be the problem. ---
**Author:** ![djgabriel2004](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.electricforum.com/djgabriel2004/32/12304_2.png) [@djgabriel2004](https://community.electricforum.com/u/djgabriel2004)\ **Post date:** [October 20, 2023, 1:39am UTC](https://community.electricforum.com/t/jerking-in-fwd-and-rev-does-not-drive/27068/27 "2023-10-20T01:39:13Z")
> [@312Bear](#): > > Then one day went to use it and it would not move How long since the last time he used it until this? Remember that battery gauge tracks amp hour going out but it doesn’t calculate self discharge or if there’s any ghost drain when car is off. ---
**Author:** ![AssyRequired](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.electricforum.com/assyrequired/32/7621_2.png) [@AssyRequired](https://community.electricforum.com/u/AssyRequired)\ **Post date:** [October 20, 2023, 1:50am UTC](https://community.electricforum.com/t/jerking-in-fwd-and-rev-does-not-drive/27068/28 "2023-10-20T01:50:50Z")
Bear- Where are you located? ---
**Author:** ![312Bear](https://avatars.discourse-cdn.com/v4/letter/3/b9e5f3/32.png) [@312Bear](https://community.electricforum.com/u/312Bear)\ **Post date:** [October 20, 2023, 2:01am UTC](https://community.electricforum.com/t/jerking-in-fwd-and-rev-does-not-drive/27068/29 "2023-10-20T02:01:05Z")
I’m in Destin, Florida ---
**Author:** ![312Bear](https://avatars.discourse-cdn.com/v4/letter/3/b9e5f3/32.png) [@312Bear](https://community.electricforum.com/u/312Bear)\ **Post date:** [October 20, 2023, 2:06am UTC](https://community.electricforum.com/t/jerking-in-fwd-and-rev-does-not-drive/27068/30 "2023-10-20T02:06:49Z")
Close to three weeks ago, He let it sit plugged in the entire time. I crawled underneath and checked battery cables from batts to controller/ contactor/motor nothing rubbing or chaffed. ---
**Author:** ![312Bear](https://avatars.discourse-cdn.com/v4/letter/3/b9e5f3/32.png) [@312Bear](https://community.electricforum.com/u/312Bear)\ **Post date:** [October 20, 2023, 2:10am UTC](https://community.electricforum.com/t/jerking-in-fwd-and-rev-does-not-drive/27068/31 "2023-10-20T02:10:19Z")
Meg them? Not sure I know what this means? ---
**Author:** ![Inwo](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.electricforum.com/inwo/32/1067_2.png) [@Inwo](https://community.electricforum.com/u/Inwo)\ **Post date:** [October 20, 2023, 2:14am UTC](https://community.electricforum.com/t/jerking-in-fwd-and-rev-does-not-drive/27068/32 "2023-10-20T02:14:01Z")
Testing meg-ohms from stator to case. Usually a special hv meter, but any ohmeter will work. Should read infinity. ---
**Author:** ![312Bear](https://avatars.discourse-cdn.com/v4/letter/3/b9e5f3/32.png) [@312Bear](https://community.electricforum.com/u/312Bear)\ **Post date:** [October 20, 2023, 2:21am UTC](https://community.electricforum.com/t/jerking-in-fwd-and-rev-does-not-drive/27068/33 "2023-10-20T02:21:33Z")
Okay I will try this in the morning. Thanks ---
**Author:** ![djgabriel2004](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.electricforum.com/djgabriel2004/32/12304_2.png) [@djgabriel2004](https://community.electricforum.com/u/djgabriel2004)\ **Post date:** [October 20, 2023, 2:34am UTC](https://community.electricforum.com/t/jerking-in-fwd-and-rev-does-not-drive/27068/34 "2023-10-20T02:34:29Z")
I’m in Boca Raton area in case you want to trailer it we can test some parts or even Reflash it to see what’s the problem. ---
**Author:** ![AssyRequired](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.electricforum.com/assyrequired/32/7621_2.png) [@AssyRequired](https://community.electricforum.com/u/AssyRequired)\ **Post date:** [October 20, 2023, 2:47am UTC](https://community.electricforum.com/t/jerking-in-fwd-and-rev-does-not-drive/27068/35 "2023-10-20T02:47:10Z")
> I removed all phase wires from the motor like @Inwo suggested. Result = no open circuit code. Unplugging speed sensor made no difference. Does it bother you that Bear unhooked the phase wires and the controller didn’t seem to notice? Or maybe Bear missed that the controller faulted? ---
**Author:** ![Inwo](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.electricforum.com/inwo/32/1067_2.png) [@Inwo](https://community.electricforum.com/u/Inwo)\ **Post date:** [October 20, 2023, 3:06am UTC](https://community.electricforum.com/t/jerking-in-fwd-and-rev-does-not-drive/27068/36 "2023-10-20T03:06:49Z")
There can also be shorted turns, but take a special test to find it. A reputable motor shop can do it. They will have a real megger too. ---
**Author:** ![312Bear](https://avatars.discourse-cdn.com/v4/letter/3/b9e5f3/32.png) [@312Bear](https://community.electricforum.com/u/312Bear)\ **Post date:** [October 20, 2023, 2:59pm UTC](https://community.electricforum.com/t/jerking-in-fwd-and-rev-does-not-drive/27068/37 "2023-10-20T14:59:04Z")
No continuity from ground to motor phases. Checked continuity between all three motor phases 0 ohms seems to be OK. ![image](https://canada1.discourse-cdn.com/flex030/uploads/electricforum/original/2X/1/1f7247e7a3c046e3ed03b274668cce30ffcfadbc.jpeg) Uploading: IMG\_3252.jpeg…]() ---
**Author:** ![AssyRequired](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.electricforum.com/assyrequired/32/7621_2.png) [@AssyRequired](https://community.electricforum.com/u/AssyRequired)\ **Post date:** [October 20, 2023, 3:07pm UTC](https://community.electricforum.com/t/jerking-in-fwd-and-rev-does-not-drive/27068/38 "2023-10-20T15:07:36Z")
Rather than use that setting on your meter can you click it one position to the left? (CCW) Does it give a different reading? ---
**Author:** ![312Bear](https://avatars.discourse-cdn.com/v4/letter/3/b9e5f3/32.png) [@312Bear](https://community.electricforum.com/u/312Bear)\ **Post date:** [October 20, 2023, 3:29pm UTC](https://community.electricforum.com/t/jerking-in-fwd-and-rev-does-not-drive/27068/39 "2023-10-20T15:29:06Z")
0.1 ohms ![image](https://canada1.discourse-cdn.com/flex030/uploads/electricforum/original/2X/c/c4ebf31ec2c3350df31d82b2f3c217d41d7eb70e.jpeg) ---
**Author:** ![312Bear](https://avatars.discourse-cdn.com/v4/letter/3/b9e5f3/32.png) [@312Bear](https://community.electricforum.com/u/312Bear)\ **Post date:** [October 20, 2023, 3:43pm UTC](https://community.electricforum.com/t/jerking-in-fwd-and-rev-does-not-drive/27068/40 "2023-10-20T15:43:56Z")
[Phases cables off the motor, KO, in gear gas pushed no faults.](https://youtube.com/shorts/hjssmBbs0Uw?si=5icq5Q1-QaZm07Ap) ---
**Author:** ![312Bear](https://avatars.discourse-cdn.com/v4/letter/3/b9e5f3/32.png) [@312Bear](https://community.electricforum.com/u/312Bear)\ **Post date:** [October 20, 2023, 7:10pm UTC](https://community.electricforum.com/t/jerking-in-fwd-and-rev-does-not-drive/27068/42 "2023-10-20T19:10:41Z")
Reads infinite/OL ![IMG_3274](https://canada1.discourse-cdn.com/flex030/uploads/electricforum/original/2X/1/179956414ba16e3731ae0b9a08631ff4dd0513fa.jpeg) [Previous page](https://community.electricforum.com/t/jerking-in-fwd-and-rev-does-not-drive/27068.md?page=1) [Next page](https://community.electricforum.com/t/jerking-in-fwd-and-rev-does-not-drive/27068.md?page=3)