Half-Shaft issue thread

[MountainBikeDude]

It's a very ambitious suspension for a new vehicle. If the adjustable travel was 3 inches or less (like most air suspension premium rides) we likely wouldn't need the splines in the half-shaft, which would eliminate the chatter. We also wouldn't have the standard height vibration that develops over time. The inclusion of the half-shaft and 7 inches of adjustable suspension was a tall order for a new vehicle.

Rivian will learn from all of these issues and pivot to more reliable parts that require less maintenance. I'm sure they stole ideas from other companies, but it's not like there is a long roster of companies installing OEM suspensions like this to reverse engineer from.

Well said, and honestly something I come back to often. I really do appreciate that they chose to be more ambitious in providing the range of capabilities they have. The cross linked "sway bar" is a Mclaren innovation, but as you said, no one vehicle could help be a Rivian how to roadmap. Highly adjustable suspension paired with high torque motors was bound to have some issue, and unfortunately the weak ingredient is the half shaft.

Found this old post which has a great cut away of a Rivian style halfshaft.

Based strictly on photos that I have seen posted in forums, I believe that Rivian is using half shafts manufactured by GKN which incorporate ball splines. Ball splines give the half shafts more axial displacement range (length change) compared to traditional half shafts. There are lots of little ball bearings inside a hollow shaft with internal grooves. Maybe that's what you heard?

You can get a pretty good look at Rivian front half shafts in the OP's video here:
https://www.rivianforums.com/forum/threads/rivian-r1t-cv-axle-failure-missed-by-service-center.7404/

Based on my internet searches, Volvo is the only other consumer vehicle manufacturer that has used the GKN ball spline half shafts as factory equipment. Unless you've owned a recent Volvo SUV or wagon, you probably have not encountered a ball spline half shaft.

The cut-away shown below is not an actual Rivian driveshaft, but it illustrates the concept.

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[kyledmb]

Appreciate all the comments, insight, and solidarity here. I think the hardest thing is that I know how my R1T was and how it should be. It was excellent just 2 short months ago. Its depressing how quickly the ride experience has deteriorated. Its now just a loose rattle can that is very cumbersome to drive, at best.

 

[Bklyn29]

It will happen if you also if you turn your wheel left or right max and hard regen at a low speed.

 

[RivianRush]

This is what I am currently dealing with. Have an appointment next week. They stated they believe it’s the half shafts as well.

I just got back from the east Syracuse Service Center and apparently I was the first vehicle serviced there. They replaced both front half shafts, which they described to me as being in very bad shape. Drove back home with no sounds so far but what I did notice was a pretty dramatic improvement to my range efficiency. I just did the same drive a week ago and avg 1.7 and today I avg 2.6. Here is to hoping that stays but I am happy with no more clunking noise.

 

[jpmc86]

The truth is, they need to redesign the half shafts, or switch suppliers. How do we get Rivian’s interest in doing so?

 

[kyledmb]

The truth is, they need to redesign the half shafts, or switch suppliers. How do we get Rivian’s interest in doing so?

I'm all for pushing this issue! We need a beefier, better engineered halfshaft for these vehicles.

 

[Jonger1150]

The truth is, they need to redesign the half shafts, or switch suppliers. How do we get Rivian’s interest in doing so?

I'd put the chances at less than 0.000001% that RJ hasn't lost some sleep over these damn things. It's the weakest point in the vehicle.

 

[CANCERDOC]

Had my vehicle at Costa Mesa this week and they did both front axles and installed new ting washers. Couldn't tell from the service write up whether they just replaced the washers and regreased everything or actually replaced the axles. In either case, the noise is gone for now.

 

[Jonger1150]

So PT00087074-D is not the current half shaft?

I'm seeing a different part number on recent service order sheets.

PT00055489-G is the new part #?

Does the R1T and R1S have different part #s?

Quad versus dual?

 

[kyledmb]

So PT00087074-D is not the current half shaft?

I'm seeing a different part number on recent service order sheets.

PT00055489-G is the new part #?

Does the R1T and R1S have different part #s?

Quad versus dual?

It makes sense that they have different part numbers based on if you have 2 drive units or 1 in the front. Just a guess.

 

[Jonger1150]

It makes sense that they have different part numbers based on if you have 2 drive units or 1 in the front. Just a guess.

I should have just asked others who have a dual motor R1T. What half-shafts PT# have they seen on recent work orders.

 

[shap]

So PT00087074-D is not the current half shaft?

I'm seeing a different part number on recent service order sheets.

PT00055489-G is the new part #?

Does the R1T and R1S have different part #s?

Quad versus dual?

Mine was just replaced (R1T Qm 23):

HALFSHAFT - FRT; R1 ORIGIN
Part# PT00055489-G

 

[CANCERDOC]

I should have just asked others who have a dual motor R1T. What half-shafts PT# have they seen on recent work orders.

For my dual motor, they listed this. Not sure if its the ting washer or the half shaft. Or a kit containing both.

Part# PT01499068-A

 

[kyledmb]

This is my front right halfshaft on my 2025 R1T TriMax.

Does this mean there might be an updated part!?!?!!

 

[RivianRush]

This is my service invoice with half shaft part # ending in G

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