Clicking Sound on Regen Braking

Will do soon. I hope it's warped rotors, or a stuck caliper slide pin... but I doubt it. The brakes work fine when the car is in N. I only have the problem when REGEN braking is being used.

 

Consider the loads on the shaft. When accelerating or cruising, torque from the differential is applied to the wheel. When coasting or braking, torque from the wheel is applied to the differential, but the differential applies a substantial negative torque (braking torque) only during regenerative or engine braking.

 

About to buy the new OEM axle, front driver's side, 43420-47040. (I understand the obsolete TSB had a replacement with a different part number. But, Toyota is now just selling the old number. Sure hope the quality is better this time.) I'm planning to do the service myself. Usually, a significant amount of transmission fluid comes out with the old axle. (At least my Highlander did.) But, with the Prius Gen4's, I think the transmission is sealed. Where would one pour in any lost fluid?

 

Transmission fill hole. If you haven’t changed your transmission fluid yet, that would be a good time to drain and fill.


iPhone ?

 

On a separate subject, I am trying to get something going on Facebook, since it seems a bit more dynamic of a place for discussions. If interested, join me at Prius Prime DIY/maintenance group.


iPhone ?

 

I'll take a look. I'm not a big FB fan, but if I can get reliable info on my Prius, I'll be a follower. Sounds like yours is "Prime" specific, though?

 

Beautiful, thank you!

 

It’s is Prime-specific, mostly because I am not a mechanic, and while I believe the 4th gen is sharing quite a bit in the mechanical department, I am not sure what exactly. I am not a fan of the FB myself. Haven’t posted anything in years. I use it for forums and groups and for background communication...you know, the way it was intended and not for political/hate campaigning.


iPhone ?

 

Careful. Prime is likely different since MG1 can aid with acceleration, unlike the Gen 4

 

I though that the latest Prius gen shares the same PSD/transaxle/transmission/whatever you call it with the Prime.


iPhone ?

 

Thank you. If those hex bolts are in the same pattern as mine, then I'll be pretty comfortable. Plus, I confirmed fitment for the driveshaft. I'll probably sign-up for a day on Toyota's TIS website, and download how to perform this job. While I'm on TIS, I download as much as I can for future maintenance, too. The TSB requires "Toyota Body Grease W" "as needed" for this job. Wondering where that needs to go? I saw some of that stuff for sale - $40+. Lol, but I'll buy it, if it makes a difference.

 

They needed to change something to enable usage of MG1 for acceleration. I thought the transaxle made the most sense for that. @Elektroingenieur should know though.

 

Indeed. I believe that photo shows a P410 transaxle from earlier Prius models. On the current P610 transaxle, the ATF drain plug is on the bottom.

The Repair Manual (more info) shows Toyota Body Grease W being applied in four places on the inboard side of the front axle assembly. This grease (Toyota part number 08887-02007) is MOLYKOTE YM-102, according to its safety data sheet (PDF, in Japanese).

You’ll also need MP grease, Toyota Genuine ATF WS, non-residue solvent, and replacements for some non-reusable parts: the drive shaft hole snap ring (90521-33002, now 90080-52017), axle shaft nut (90177-22001, now 90080-17238), and gaskets (quantity 2, 90430-18008) for the transaxle drain and filler plugs. See catalog Figure 39-01, Transaxle Assembly; Figure 43-02, Front Drive Shaft; and Figure 43-03, Front Axle Hub.

The removal procedure specifies some special service tools: the drive shaft nut chisel (09930-00010), drive shaft remover attachment (09520-01010), and slide hammer (09520-32040).

Prius Prime cars have a transaxle with a similar basic design, but there are some differences, including a one-way clutch between the engine and the transaxle. See my October 2018 posting.

 

* This man does not do half measures.

 

Feeling some competition??

 

Here are the fill and drain locations on Gen4/Prime. Note that the fill hole is at the very rear of the transaxle, so you need to have the car level to get the right amount in there.

 

Great info, thanks!

I watched an 'A1 Auto' video that was posted somewhere on here, which performed the front-left replacement on a Gen3. That one didn't have a snap-ring. So, it seems that they added the snap-ring on the Gen4. I did both front drive shafts on my 09 Highlander. Only the front-right had a snap ring, and carrier bearing. The left axle pushed right into the transmission with a c-clip around the axle splines. I didn't empty the ATF. I measured how much came out with the axle, then I topped it off with the same amount.

I'll pay the $20 bucks soon for a day on TIS. All the research that I do online will get compared to what TIS says. I always rent the slide hammer from Autozone; and I'll need to rent their torque wrench -- mine only goes to 150 ft / lbs. Their slide hammer comes with some attachments. Hopefully, I won't need the special service tools -- sometimes those are a must -- but usually I can work around it.

 

I downloaded the TIS repair manual for this repair. Before I order a new axle, I'm going to get some "grease" as mentioned above, and apply as per the repair manual to my current axle. Maybe the axle itself has no problem, since Toyota has reverted to the old part number, and the TSB is obsoleted. And, MAYBE it just needs grease. I do find it odd that you have to grease the outside of an axle -- which is another reason I think this could be the fix! It's worth a try -- if it doesn't work, I'm only out an axle nut! [Btw, the TIS is a bit unclear to me exactly where to apply the grease -- even with the diagrams -- but I'm pretty sure that after I get in there, it will become clearer.]

 

I can't find MOLYKOTE YM-102 anywhere to buy online. Any ideas? I probably have to bite the bullet, and pay Toyota 43 bucks for this!

 

How's the axle holding up?