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So I've been reading a little bit about the RDM issues as of late. And what I have collected is that pretty much, these things will eventually fail at some point...there's no going around that.....is that true? I'm starting to drive my car super conservatively now as not too put too much pressure on the RDM...will that help? I've driven my car over 8000 great miles and now I catch myself leaving the radio off to see if I can hear anything...& sometimes I do :huh:
 

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What is it you hear? If its the usual growling/spline rattle, I've heard that from day 1 of having my Karma and I think they all make that noise.
 

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The sound you hear, the GROWL, is from the clearance between the shafts of the RDM and the motor splines. IT IS VERY LIKELY THAT MOST WILL FAIL without some sort of intervention. On take off and on decelleration the motors are basically pulsed for a smooth transition. This means the splines are being beaten forward and back against the RDM shafts. Because, in most instances, the motor splines are softer they wear the most. The hardened motor splines will LIKELY last longer, but as with most things Fisker you are the Beta Testers. The hardened splines tend to make more noise on a high speed decelleration in hill mode 2. There was a huge up-roar in Europe about the noise as many of their highways allow for greater speeds. To combat the issue we were doing the same thing we did for low speed growl. LOCTITE!
 

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If Loctite is the solution, then that's a joke. It is used to cement nuts and bolts together. To expect that it will hold up to the pressure of an electric motor against a shaft accelerating or slowing a 5300 lb mass of car sounds ridiculous. Its like using Elmer's glue on a freight train to pull a building! Makes no sense at all. How the engineers at Fisker Automotive could think that Loctite would be a workable permanent solution to the problem is an enigma!
 

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If Loctite is the solution, then that's a joke. It is used to cement nuts and bolts together. To expect that it will hold up to the pressure of an electric motor against a shaft accelerating or slowing a 5300 lb mass of car sounds ridiculous. Its like using Elmer's glue on a freight train to pull a building! Makes no sense at all. How the engineers at Fisker Automotive could think that Loctite would be a workable permanent solution to the problem is an enigma!
This is a quite common application for securing a gear to a shaft for industrial machinery. You would be surprised how many auto manufacturers utilize Loctite on axle components of vehicles (or to stop stripped bolts in general). The red loctite is permanent
 

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So how do I loctite my car???
Pull the RDM, Pull the TM's off the RDM and Loctite the splines.

I am of the old school of thinking that Loctite will not really make that much of a difference if you have a good RDM/TM's. I have ridden in Karma's that have the spline chatter at low speeds/reverse with 25k miles. In the long run I don't think it will matter much. I think it sounds a lot worse than it is. The tolerance is close enough where it won't make that much of a difference. The soft splines were a whole different issue and with/without Loctite the splines would have eventually spun out due to the manufacturing defect.

If you are going to pull the RDM (especially on early Karma's) just to do the Loctite you might as well replace the whole RDM with a late model unit- rather than just use loctite on your old TM's/RDM. Of course you are better off waiting till it fails as RDM's and TM's are not cheap.
 

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Does loctite also eliminate the growl/spline rattle altogether? That might just be worth it for the acoustics!
 

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RDM's & TM's are not cheap.....what is not cheap? How much are we really looking at, parts & labor, if/when these fail?
 

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RDM's & TM's are not cheap.....what is not cheap? How much are we really looking at, parts & labor, if/when these fail?
Probably 12k-15k for a complete RDM assembly (with traction motors and differential). Not sure what dealers are charging for R&R but it would take roughly 10 hours. The most time consuming part is removing the RDM from the subframe and aligning the new one into the subframe. Even more time if you are re-using your old RDM and just pressing in new TM's. Pretty straight forward as long as you have the correct parts. Just did one last week as a preventive repair and it took 8 hours.
 

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just to FYI you they make loctite to hold gears and loctite to fix spline issues. There are a larger number of drivers in europe with loctite. Mostly on the newer motors with the hardened splines.
 

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Smooth, you did one yourself? Are you a mechanic or just a mechanically inclined owner? Is it something a mechanically inclined owner could accomplish on their own or does it require a professional mechanic to install? Are the RDM's and Traction motors even available from whomever manufactured them? $15k is a lot of scratch, I wonder if the manufacturer has any liability if FA wont honor the warranty? Thanks
 

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Smooth, you did one yourself? Are you a mechanic or just a mechanically inclined owner? Is it something a mechanically inclined owner could accomplish on their own or does it require a professional mechanic to install? Are the RDM's and Traction motors even available from whomever manufactured them? $15k is a lot of scratch, I wonder if the manufacturer has any liability if FA wont honor the warranty? Thanks
I think any mechanic could pull the Transaxle and RDM. Once you pull the rear bumper off, trunk liner and disconnect the HV cables from the TM's and Inverters it is pretty simple (i.e. remove 4 bolts on the back of the transaxle and lower it via scissor lift).

Nobody will honor the warranty you are pretty much stuck paying for the full cost of these parts. Many dealers have the JJE TM's I think they run $3700 a piece. Another option is you could have a new spline machined and re-use your old TM's. Many of these RDM's are not that bad and I believe can be fixed by a machine shop. If you want to go the new route I think Fisker SV has a few TM's in stock. Obviously it is easier to replace them with new/updated components but if you are savvy enough your old components can be repaired and improved. I know a few machine shops now have 3D scanners and can basically replicate any part and machine a new one. Probably cheaper but not sure as I have not tried this service as yet.


If you are comfortable mechanically you may want to pull your RDM to do the Loctite to see how it works. Nothing can really go wrong if you have the proper tools (i.e. Lift, engine hoist, scissor lift) and work slowly/methodically the first time. Also make sure you remove the HV Battery fuse underneath the rear driver side passenger seat.
 

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Smooth, you did one yourself? Are you a mechanic or just a mechanically inclined owner? Is it something a mechanically inclined owner could accomplish on their own or does it require a professional mechanic to install? Are the RDM's and Traction motors even available from whomever manufactured them? $15k is a lot of scratch, I wonder if the manufacturer has any liability if FA wont honor the warranty? Thanks
He left out the fact that the first one he saw, he had me there doing it and him helping out. :)
 

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I'm pretty mechanically inclined and have a metal fab shop, but I was wondering if Lormax/ Smooth Op or Harley guy could explain the difference of the RDM (rear drive motor?) vs the TM (traction motor?) and how they interact together. I thought there were just two opposing motors on either side of the differential?

Also has any one ever figured out how we know for sure if we have an early car?
I have some interesting stickers in my engine bay that show my car had at least 2 Repair campaigns done to it....but if I remember right the dates on them are something like a year prior to the date on my cars door sill stamped production date placard.
I hope I don't curse anything but thankfully my car is super quiet still with about 16,000 miles on it.
Thanks in advance as always for any light you can shed on this.
 

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RDM = Rear Drive Module. Think of it as the differential itself. The TM's are the motors that turn it.

The campaign stickers you have should be for at least the cooling fan recall, and possibly the battery recall for the hose clamp check.
 
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