My M35x Front Driveshaft Replacement Thread

[picoman]

For a little over a year I have been able to hear my u-joint make a light metallic “clink” when shifting from park to reverse or park to drive. Today it got a bit louder so its now time to replace it.

This is the freeplay I am currently dealing with:
https://youtu.be/GcX2MdGz0AE

Not as bad as some ive seen but I surely dont want this thing letting loose and taking other things out with it.i

I bought a replacement driveahaft from wholesaleimportparts.com for $209.50 shipped

I plan to try this shortcut:
https://youtu.be/QFR91UeBDTg

Hopefully the new shaft arrives sometime this week. I will update with how the above mentioned shortcut works/doesnt work

[steve_c]

picoman,

Before you install your new shaft, can you try to get the #'s off the U joint assembly, (just the actual joint itself, not the shaft). If you can do same for the old joint, please post any #'s you can for the joint itself!
Save that old shaft, might be able to install new joints in it if we can find the #'s for it!

Thanks

[midnightclub619]

That's a cool trick! Let us know how it goes.

[eQlipse]

That shortcut won't work for the M35X as far as I can tell. Just did this a few months ago. Probably the same amount or more work dropping the steering rack as it is taking the pass side cat out. No need to mess with the transmission case at all.

[picoman]

Thanks for the feedback. I will pick up some exhaust gaskets just in case I need to drop the cat. It would be nice not to fight the corroded hardware though.

[picoman]

So I have been checking on gaskets and am trying to find something local/2-day shipping just in case I have to resort to cat removal and so I can work on it on Friday.

O'reilly shows both upstream and downstream for special order but when I call to order I am told they cannot order them. AutoZone shows the downstream gasket only. Nissan dealer shows the upstream gasket as being on "delete status" which means they are about to stop carrying it, but they dont have any on hand. Infiniti dealership can get the gaskets tomorrow for $38 on the upstream and something less on downstream. They also charge $7 a piece for the nuts .... sheesh. Im going to take another look at things tonight as im not having much luck with the gaskets at the moment. I'd rather not spend $30 on shipping for something I may not use.

[picoman]

I ended up starting this repair Friday evening and completing this repair Saturday around noon. Probably 5 hours total but it could definitely be done in under an hour if the catalyst hardware cooperates and you don't try to take a shortcut like I did.

This is not intended to be a comprehensive step-by-step instruction rather just a few notes about my experience that may help guide and prepare someone else who is about to do this job.

My goal was to have this job done in under an hour using the above mentioned shortcut from the Youtube link. The shortcut being removing the steering rack instead of lowering the transmission case and removing the catalyst.

I tried hard to make it work without removing the cat but it just was not meant to be. I did not remove the steering rack because it didnt look like it would help. The steering hard lines (shown in the last photo) were in the way despite removing the 2 mounting brackets and they were at serious risk of damage/puncture while trying to get the shaft out without removing the cat.

I faced the harsh reality that I would need to remove the cat, but it was worth a shot trying out the shortcut. I had sprayed PB Blaster on the cat hardware the day before JUST IN CASE I needed to remove it and to help with my odds at successful fastener removal. It paid off. I did have to resort to a torch, angle grinder, dremel, and damaged hardware removal tool on one of the cat outlet nuts though. Once you get all of the cat. hardware removed you are welcomed with a new issue: the cat is wedged in place by the exhaust system. You need to either remove the y-pipe, or remove the studs from one end of the cat. I ended up removing one stud from the inlet of the cat. This was the lowest stud and easiest to access from under the car. It uses a 6 point Torx (T18?) socket. PB Blaster was again a good friend and probably helped me avoid some unnecessary cursing and drilling. Once the lowest stud on the cat was removed, the cat came out readily. The transmission/transmission case cross member was supported by a jack and unfastened from the chassis. The transmission case was dropped a few inches and the driveshaft came out easily.

The splines on the new driveshaft came pre-greased but I have a tube of expensive Sachs spline grease that I only got to use once, so I slathered it up some more to make myself feel better about buying the expensive tube of spline grease a year ago for my other car.

Installation is the reverse of removal etc etc.

One thing that I did do that added quite a bit of time was chasing all the threads on the nuts and screws and threaded holes. Some of the hardware felt like it was going to snap on the way out and some more felt like it was going to snap during reassembly so I cleaned up all the threads and felt a lot better about myself. Everything was an M10x1.25 tap/die which applies to all the fasteners that use a 14mm socket.

Not a terrible job, and I feel fortunate to have only struggled badly with 1 nut. It was frustrating for a while but now that its done im glad to have saved the $800+ that a shop would have charged.

For anyone planning this repair, I would say to arm yourself with PB Blaster and apply it a few times in advance, a torch, a tap/die, dremel/angle grinder, and a 4 leaf clover.

here are a few images now


A closer look at the new driveshaft u-joint, sorry Steve, there were no part numbers or markings that could be used to identify anything. Its nice that these are replacable and can be greased.





The new shaft comes with instructions and torque values which is nice


These are the power steering hard lines that get in the way

[picoman]

Oh and one more thing. The replacement cat. outlet gasket I got from Napa was nothing like the MLS gasket that came off the car. Being MLS, I sanded it clean and applied copper RTV. Same goes for the inlet gasket. reused with copper RTV.

[ae7456t]

Very impressive, @picoman...Unfortunately, I went through this 3 months ago, and let the shop do it for me, because I was worried about the rusted hardware on the cat, and supporting the transmission case (sounds like you can relate).

I can confirm that you did, in fact, save ~$800...not including the warm glow that comes with fixing it yourself v. the hollow emptiness of paying for it (my bill was ~$1000, including the driveshaft, itself).

Well done, and thanks for paying the experience forward for the rest!

[picoman]

Yes, it had almost become one of those repairs where you lay your head back on the creeper, relax for a bit and somewhat hope the car falls on you. That or you swear that once its complete you will sell all of your tools and dedicate the rest of your motoring days to 2-year Toyota Camry leases. Once its back together and you have driven it a bit, then the satisfaction can start to set in. It wasn't THAT bad, but the cold weather, the partially lost weekend, and thoughts of "oh crap I need to drive this thing on Monday so I better succeed" all become nuisances

I was really hoping to do a well documented writeup for the FAQ on how to use the shortcut but that obviously didn't end up working so all I can contribute is a few personal notes on top of the currently accepted procedure that will hopefully be of some use to someone down the line.

[steve_c]

Picoman,
A+ write up, and I am sure the moderators will agree that this is an invaluable contribution to the M forum!
Well done sir!

Did you need to return the old shaft? If not, can you post pics of the end caps on the joint so we can see what method of retention used to hold them in place?

Can you measure the entire length of the U joint, cap end to cap end, and also the circular circumference of the cap itself?

Lastly, if you had a U joint in your hands at the time, would you have been able to install it without removing the drive-shaft from the vehicle?

[picoman]

I will take some measurements for you this evening

There was no core charge on the old shaft, so it will remain on my garage floor until I can figure out something to do with it/muster up the motivation to walk 10 steps and place it in the garbage can.

[picoman]

They are staked, but you probably already knew that.



The closest match I can find based on the measurements I took with my caliper is this: Moog 811 https://www.summitracing.com/parts/mog- ... gLukPD_BwE

it was difficult to measure accurately so I will have to saw the u-joint off and tap it out to get a better measurement of the bearing since a retaining ring would need to be factored in to the overall dimension.


Info on replacing staked U-Joints here: https://www.f150forum.com/f72/replacing ... ts-175529/

[EdBwoy]

Yes, it had almost become one of those repairs where you lay your head back on the creeper, relax for a bit and somewhat hope the car falls on you. That or you swear that once its complete you will sell all of your tools and dedicate the rest of your motoring days to 2-year Toyota Camry leases. Once its back together and you have driven it a bit, then the satisfaction can start to set in. It wasn't THAT bad, but the cold weather, the partially lost weekend, and thoughts of "oh crap I need to drive this thing on Monday so I better succeed" all become nuisances

I was really hoping to do a well documented writeup for the FAQ on how to use the shortcut but that obviously didn't end up working so all I can contribute is a few personal notes on top of the currently accepted procedure that will hopefully be of some use to someone down the line.

I defintely relate to this entire post. Every time I have busted and bloody knuckles, I ask myself why I put myself through this mess.
Seriously, thanks for sharing your experience, and in trying to see if the shortcut works for fellow M owners. Your contribution is appreciated.

[Ilya]

Adding this to the FAQ for posterity.

[midnightclub619]

@picoman - thanks for the update and writeup. Glad to hear that it all worked out in the end. I feel ya, the hands on approach is sometimes worriesome if your going to finish on time but when you complete the work, that feeling is great. nice work

[steve_c]

@picoman - thanks for the update and writeup. Glad to hear that it all worked out in the end. I feel ya, the hands on approach is sometimes worriesome if your going to finish on time but when you complete the work, that feeling is great. nice work

Agreed...
What makes this job a potential nightmare is one's ability & resources to remove & reinstall the cat & any exhaust components that might be compromised / damaged by rust. Especially for all in the rust belt climes!
Once you start fooling with those, there is no turning back!

It is usually the front joint that goes bad on these shafts, from what I see posted. Is it possible to service that U joint with the shaft hanging & not fully removed? If so, all the mess dealing with the exhaust can be eliminated.
As far as staked joints go, their is a company that provides replacement joints for OEM staked applications. These joints utilize inboard C clips. Check this out:

http://rockforddriveline.com/atv-utv-li ... n-u-joints

Now, if we can only get the exact dimensions of the OEM joint to match up to a Rockford U-Joint replacement.

[eQlipse]

That shortcut in the youtube video was for G35x I believe. That's why it doesn't work on our cars. It seems it could but also seems to be more work than removing the cat. My time consumption was spent on rusted components living in the midwest. I too re-used the old gaskets with RTV due to lack of availability.

[TN_INFINITI]

Sorry for reviving an old thread, but my 08 m35x needs a new front drive shaft, too.

How do I get my drive shaft to rotate? I'm struggling to reach 2 of the bolts on the butterfly mount and my shaft won't spin.

I've got it in neutral and front wheels are off the ground.

[EniGmA1987]

Sorry for reviving an old thread, but my 08 m35x needs a new front drive shaft, too.

How do I get my drive shaft to rotate? I'm struggling to reach 2 of the bolts on the butterfly mount and my shaft won't spin.

I've got it in neutral and front wheels are off the ground.

The driveshaft sends power from the front of the car to the rear differential that connects to the rear wheels. So I would think the rear wheels must both be off the ground otherwise they will keep the diff "locked" and the driveshaft wouldnt be able to spin.

[VStar650CL]

The driveshaft sends power from the front of the car to the rear differential that connects to the rear wheels. So I would think the rear wheels must both be off the ground otherwise they will keep the diff "locked" and the driveshaft wouldnt be able to spin.

Yep. Jack the back, Jack.

[TN_INFINITI]

Xmas p]Thanks.
Yup, jacking the rear wheels allowed me to rotate the drive shaft.

Sadly, my new drive shaft does not seem to be balanced (i can see the welded balancing weight?)

I really don't want to tackle this job again, although it will be soooo much easier a second time (all my exhaust bolts are loosened)

[EdBwoy]

...
Sadly, my new drive shaft does not seem to be balanced (i can see the welded balancing weight?)
...

Actually, the fact that you can see the welded attachments is evidence that the driveshaft is balanced. Or at least, that an attempt was made to balance it.

Very few rotational elements are perfectly internally balanced at the point of manufacture. Even if they are statically balanced, once they get to speed, their imperfections show (just like wheels)...and once again, since there's very little you can do inside a driveshaft, welding stuff to the outside shell is the best you can do.

Driveshafts aren't usually pretty. As long as it came from a reputable manufacturer/has a warranty, I wouldn't be too concerned.

[EniGmA1987]

Xmas p]Thanks.
Yup, jacking the rear wheels allowed me to rotate the drive shaft.

Sadly, my new drive shaft does not seem to be balanced (i can see the welded balancing weight?)

I really don't want to tackle this job again, although it will be soooo much easier a second time (all my exhaust bolts are loosened)

Apparently, you can balance the driveshaft at home when it is installed on the car:
https://youtu.be/zuPSGJZpL3k

[TN_INFINITI]

...
Sadly, my new drive shaft does not seem to be balanced (i can see the welded balancing weight?)
...

Actually, the fact that you can see the welded attachments is evidence that the driveshaft is balanced. Or at least, that an attempt was made to balance it.

Very few rotational elements are perfectly internally balanced at the point of manufacture. Even if they are statically balanced, once they get to speed, their imperfections show (just like wheels)...and once again, since there's very little you can do inside a driveshaft, welding stuff to the outside shell is the best you can do.

Driveshafts aren't usually pretty. As long as it came from a reputable manufacturer/has a warranty, I wouldn't be too concerned.

I'm going to jack it up this afternoon and see if anything looks loose or out of sorts.

My mind is racing with thoughts that I messed something up when I removed the transmission axle brace. I supported it with a jack, but that brace was a bear to get off and put back on (kept getting hung up on the transmission bushing). Or I got a bad drive shaft?

I know I need to tighten my steering rack, because it makes a loud popping noise when I turn the wheel. Hopefully that is my problem and not an unbalanced drive shaft.