Hello,

I really didn't know much about this topic until getting an SC400 drive shaft for my SC300 Aristo swap. After accidentally pulling the new 'shaft in half while taking it out of the box I realized I needed to learn about it

Common drive shaft knowledge says that the two halves of the DS should be "in phase". What this means is that the shaft is assembled so that the yokes on each end are in the same position rotationally speaking. Being told this I put my DS back together "in phase" as close as it would go. I found it odd that the splines prevented it from aligning exactly this way.

Anyway, I just found some info straight from the big T that seems to be saying the DS should be "out of phase", see below:



Does anyone know which is correct? How are the flanges oriented on your SC400 DS? Are they "in phase" (aligned when sighting down the DS) or are they "out of phase" (180deg opposite as in the pic above)? Thanks!

Phil

 

Wow. I just put my gte in with a 400 driveshaft as well. Haven't tightened anything down yet. I had no idea about this. I need to know as well.

 

In addition to phasing, it's also about entire driveshaft balance. The DS is balanced as one entire unit at the factory and if disassemble, needs to be re-assembled back exactly the same way. Actual instructions from the factory mannual is to mark the splines before disassembly and match them back up during reassembly.

 

Right, you are supposed to mark it before pulling it apart, which obviously you can't do anymore. However, on most SC3's, if you look very closely, you'll see some factory yellow markings for DS alignment. I can't speak for the SC4's.

If it isn't aligned, you'll feel a "wobble" between 2 and 5mph. Obviously, if the balance is bad, you'll feel a vibration at higher speeds.

Ian

 

OK. New issue in addition to the phasing. I put my engine and transmission in last week and it looked like everything was cool. Got under my car today to do some finishing touches and the bolt holes from the forward donut don't line up with the back of the Aristo Tranny. Did I miss something? I don't think I have the diff and output donuts mixed up because the one on the diff looks great and lines up perfectly. It's all a 3 bolt assembly, the bolt holes are just off by about half a bolt hole vertically. All three.

SC300/GTE Aristo-auto swap with SC400 driveshaft.

 

The flange on the Aristo trans has a slightly larger bolt circle than the SC400 so it won't fit. You can get the SC400 trans flange and put it on the Aristo trans which is what I did. I've also heard of people elongating the holes on the Aristo flange.

Phil

 

Yeah, accidentally pulling the shaft apart sucked, as soon as it happened I knew I was sol in terms of balance. I looked all over the DS for some kind of markings but couldn't find anything to index it back. Also, according to the factory manual it sounds as if the hole thing, including the rubber donuts are balanced as an assembly. They say to mark not only the DS halves but also the donuts and flanges.

With my DS aligned sort of in phase I was getting a very slight, almost unnoticeable, "buzzy" feel in the seats at 65 or so. Lower speeds and acceleration were smooth. Last night I took the DS out, pulled it apart and put it together with the flanges out of phase by 180deg (like the pic above) and also lined up the u-joint to the flange as best I could by looking at a picture of an SC DS on ebay. Initial driving is good. The really slight "buzz" seems to be gone. I'm going to leave it alone for now and figure to be perfect I'd need to replace the whole thing at which point I would rather throw in a custom 1 piece DS and ditch the donuts.

Phil

 

One piece sounds good....

 

WOW, I have this exact same problem. I pulled everything apart and didnt mark anything. I was thinking that I needed to mix match a supra shaft for my swap. Mine is a gs300. But anyways, How would someone go about bringing back to how the factory setting was? Do you take it to a drive shaft shop and have them balance it? If thats the case, then you would have to take the entire shaft off...from flange at tranny to flange at differential. Even then how would they balance the entier piece?