KahnBB6

iTrader: (5)

I just have an R154 installed in my SC300 and at first I used a mystery R154 front driveshaft that was too short on the splines and allowed oil to leak from the trans.

Today I replaced that with a Supra MKIII R154 front driveshaft and once again swapped the SC carrier bearing.

The car drives fine and the seal is contacted but something is rattling at the carrier (I suspect) that was NOT rattling with the shorter R154 front shaft.

Can anyone help me figure out what's going on?

stockhatch

iTrader: (12)

Could be a vibration caused by a balance issue. Try indexing the shafts and see if that alleviates the noise.

KahnBB6

iTrader: (5)

Strangely, it was BAD when the MK3 driveshaft went in with my SC carrier. After I drove it around town a bit, rattling away and parked it for a few hours... no more rattle. At all! I can't explain that unless driving it and going into reverse a few times somehow seated something in the carrier that was a bit loose before.

If the noise returns or another noise crops up I will remove it and have it rebalanced. It's a bit strange for a very obvious noise like that to just up and disappear but I am not complaining.

Update: Well, it hasn't totally gone away. The vibrating/loose washer sound appears to come back momentarily once in a while but it goes away. Acceleration/load makes it worse for a moment but it goes away quickly. This has to be something to do with how the carrier bearing was installed. I'm checking into it soon but it's a rare occurrence now.

KahnBB6

iTrader: (5)

Okay, I've identified what is making the noise. The MKIII R154 driveshaft is so close to the end of the transmission it is actually skimming metal on metal with the end of the tailhousing. Note the R154 tailhousing metal cover has been removed for clearance.

It did sound like a loose washer initially but now that I've been hearing it more, this was definitely the driveshaft collar hitting the trail housing of the transmission slightly.

This happens under load mostly and happens within five to ten seconds of holding any particular speed. I can only stop it from happening by pulsing the accelerator every three seconds-- very annoying and a bit scary.

Is the MKIII R154 driveshaft supposed to be engaged this closely to the transmission? The previous incorrect shaft barely had any engagement but this one has far too much from the look of it.

Also, is it possible that a bad center driveshaft carrier bearing can cause this, since the problem seems to come and go?

I'd appreciate any advice you have, guys because right now I don't feel comfortable driving the car long distances until I have this issue fixed.

For the record, I did not swap the SC carrier onto the MKIII front shaft myself. Is it even possible to assemble it incorrectly??

KahnBB6

iTrader: (5)

I also found this interesting reading of SF regarding this subject:

http://www.supraforums.com/forum/sho...properly/page3

KahnBB6

iTrader: (5)

So as far as I can tell I have three options:

1) Replace the OEM SC carrier bearing. It's possible there is play in it causing the shaft to move back and forth.

2) Remove the driveshaft and trim the metal dust collar on the input side (and possibly still replace the carrier)

3) Buy a whole 1 piece driveshaft which has no collar.

Any thoughts on the picture, guys?

JesLet

iTrader: (19)

I had the same problem when I first installed my R154, It was that metal shield. I trimmed it in half, no more noise

Edit: I've put 40k+ miles on that used R154 and still holds fine!

KahnBB6

iTrader: (5)

JesLet, thank you! So this isn't a fluke issue? Edit: I just reread your post. So cutting of half the collar area solves it?

So far tonight it hasn't happened again but it was doing it ALL afternoon during rush hour. Just covering all my bases, would the carrier bearing still be suspect since it seems this has to do with driveshaft play? It's never been replaced.

I've been hearing as much about these R154's. The transmission guy who rebuilt mine said the one in his MKIII was just over 200k unrebuilt and still going strong. He's still on his stock turbo and he said the R-series are good through at least 400k without a rebuild.

s13erm

iTrader: (3)

bumping an old post. Did you ever get this resolved? Sounds like I may be having the same issue, wondering if trimming that dust shield helped.

KahnBB6

iTrader: (5)

s13erm, I ended up removing the dust shield but it's been my intention to find another one. The strange issue persisted until it didn't any longer. I think the clearance problem must have been very minute or else the carrier bearing did need to settle. Actually I'd put way more stock in the clearance theory.

I haven't had this reoccur in the three years since. Long term I do want to find a real Soarer R154 front driveshaft but this is not necessary.

If you have the same issue with an MKIII R154 front driveshaft I would remove your dust shield.

s13erm

iTrader: (3)

Awesome thanks for your reply!
I have a weird rattle issue at 2000rpm (3rd or 4th gear) and the symptoms were similar to yours. Would go away once i accelerate past that rpm range.
I already removed the dust shield on the tail housing (cup shaped) as I had some previous clearance issues. I'm using an mIII front half shaft as well. Your picture above with the red circle, did you remove that dust shield that is on the driveshaft? Thanks for your help!

KahnBB6

iTrader: (5)

Well, as long as you have the issue I would continue to monitor it. If you have the car in for service on a lift for some other reason I'd always take the opportunity to give that area a quick inspection just to be safe. In my case though I haven't had it persist.

I think the issue is probably that the Soarer R154 front driveshaft is the most ideal solution. However as they are hard to come by and can be easily confused with an SC300 Auto driveshaft without a direct comparison up close (someone scammed me with this trick) we tend to use the MKIII versions.

There is also the alternative of getting a custom driveshaft made but I prefer the factory center bearing design for a 99% street car.

In that picture above (Post #4) I did have the dust shield removed, yes.

KahnBB6

iTrader: (5)

2020 update:

This issue reared its head again in a slightly different way after I reinstalled my Torsen rear differential. The bottom line is that the Supra MKIII R154 front driveshaft is too long and needs to be professionally shortened by 3/4", welded and re-balanced. It is engaging too much on the back of the transmission.

I purchased a brand new OEM dust shield a couple of years back and I will be painting it and reinstalling once I can get my front driveshaft modified to the correct length.

Where before there was some noise it made by cutting into a little of the metal at the back of my R154's tail housing now that input shaft is I think bottoming out at the back of the transmission under some circumstances. So now this underlying issue must be corrected to be kind to the entire driveline.

An alternative to shortening the MKIII R154 front driveshaft 3/4" (or at minimum 1/2" but 3/4" appears to be closer to what is needed after measuring) is to use a common SC300 Automatic front driveshaft and send that out to a professional driveline shop to be extended by 50mm / 1.96 inches, welded and re-balanced. Or if you can find a unicorn, a Soarer R154 front driveshaft *should* be the correct length to bolt in as-is.

The dust shield really should be left on the back of the transmission after having modified either driveshaft for the job.

What is should look like back there with a correct length front driveshaft is this:



(Here I am using an example image from another forum thread of a Celica MKII with an R154 swap but the way the driveshaft sits at the back of the R154 is the relevant part to pay attention to).

This is as far as you want the front driveshaft to sit relative to the R154's rear dust shield cup edge. This should be the case regardless of whether you stick with Toyota's center bearing supported two piece factory driveshaft setup or a fully custom made one piece driveshaft.

DJDGTE

Thanks for this follow up, @KahnBB6 ! Has anyone else had this experience using a front MK3 R154 driveshaft? I was about to go buy one this weekend, but now I'm back to the idea that you've said - extending the original automatic one, or going 1 piece. Thanks

KahnBB6

iTrader: (5)

Many others over the years have noted the issue of the MKIII R154 front driveshaft being slightly too long in an SC or Soarer but they, like me, made it work one way or another.

Once I was swindled after buying an SC300 Automatic front driveshaft that I *thought* was a true Soarer R154 front driveshaft I realized later that it really makes the most sense to take that SC300 Auto front D/S and have a professional driveline shop lengthen it by 50mm/1.96 inches. And then have them balance it. Then it will be *exactly* like a factory Soarer R154 front driveshaft and fit as pictured in my last post above.

I only modified my MKIII R154 front driveshaft to make it 1/2" shorter because at that time I couldn't find an SC300 Auto front driveshaft for sale to recondition and have extended. So I just kept what I already had and got that modified.

MKIII R154 front driveshafts are not as common as the SC300 Auto front driveshafts. The MKIII version has a bulge in the middle that makes modification more of a challenge. It also has a much larger yoke that absolutely needs the shortening (again 1/2" shorter at minimum but *precisely* 3/4" shorter ideally) in order to clear the dust cup on the back of the transmission.

Given all of that and the benefits of retaining the factory two-piece driveshaft system I'd recommend just getting your perfectly good and strong SC300 Auto front driveshaft extended and re-balanced. It's a straight pipe so this makes it much easier for the driveline shop to do.

Plenty of MKIII Supra owners still want those MKIII R154 front driveshafts to fit their cars.

But if you find a great deal on the MKIII version then you can absolutely have it shortened to fit and avoid the clearance issue just the same.

Both are good and extremely strong driveshafts that can achieve the same ultimate goal.

....

Aside, the MKIII R154 front driveshaft has this length difference simply because the 7M-GTE engine and matching 7M-R154 bellhousing are that much shorter than their JZ counterparts in the same car. I suspect that a factory 1JZ-GTE powered JDM Supra MKIII Twin Turbo R front R154 driveshaft would probably bolt right into an SC with an R154 and JZ engine. Not that those parts grow on trees mind you but just to prove a point I mention this.

....

Bottom line:

If you have an SC300 Automatic that you're converting to use an R154, just get your SC300 Auto front driveshaft extended +50mm and have it rebalanced (you may need to bring in the center bearing and rear driveshaft along with it to get the best possible balance at the driveline shop).

You already have the part that you can convert into the 100% equivalent of a genuine OEM Soarer R154 front driveshaft.

Either with the SC300 Auto front driveshaft or the MKIII Supra R154 front driveshaft both need a little modification in order to be a true correct fit. The MKIII R154 version just fits very tightly with the transmission tail housing dust shield removed (which is totally unnecessary to remove if you get it done right).