Differences in old vs new SADS design?

[maestro123]

I have a '93 Previa. I've read that there was an updated design to the SADS drive shaft beginning with the manufacturing date 01/94. I've seen recommendations for just getting a newer driveshaft and using the newer coupling kit, while I've also seen elsewhere about just getting a coupling set for the old design. I'm hoping some of the Previa gurus can chime in here. What exactly is different between the old and new designs for the SAD shaft? Is it just the 94 and newer bushing holes are 14mm OD, while the 91-93 bushing holes are 12mm OD? Is there anything else different that make the newer designs better?

[mountainhick]

Yes, most importantly SC vs NA have different bolt hole sizes. SC shaft itself is also a bit beefier

[TheMAN]

Yes, most importantly SC vs NA have different bolt hole sizes. SC shaft itself is also a bit beefier

it was upgraded/redesigned for the S/C, based on experiences gained from 3 years worth of Previa production/repair... but the S/C wasn't the only ones that got the upgraded SADS... the N/A did too (it was available in other countries till 1999)

[maestro123]

Pardon my ignorance, but what does N/A stand for? I'm guessing S/C must stand for supercharger right? Also, would you guys recommend getting the newer driveshaft, if I have the older one?

[mountainhick]

NA=naturally aspirated,
SC supercharged.

The SC shaft is beefier, but not necessary for your car. If you want to spend extra money it is up to you.

[TheMAN]

the updated SADS withstands vibrations and abuse better... if you plan to keep your previa till "the wheels fall off" like I am, then get a used 94+ shaft from the junk yard, then buy the replacement coupling kit from Toyota.... it is much better than the original

[maestro123]

then buy the replacement coupling kit from Toyota.... it is much better than the original

I found that the replacement coupling kit 04374-28011 is $250 at my local dealer. A little on the pricey side. Are they worth the extra $$$?

[TheMAN]

it does not fit the pre-94 shafts

[timsrv]

I found that the replacement coupling kit 04374-28011 is $250 at my local dealer. A little on the pricey side. Are they worth the extra $$$?

The Toyota price is hard to swallow, but needing to do the job again after only 30k miles is even harder. Toyota has proven their couplers last around 150k + miles. I'm not aware of any aftermarket ones lasting this long. Of course correct installation is critical. Regardless of what you use, make sure to follow the service bulletin procedure exactly. And like TheMan says, the new OEM couplers won't fit the old shafts. If you buy OEM couplers, go find a used 94+ shaft in the salvage yard and install them on that. Tim

[TheMAN]

I wonder if it's possible to cheat replacing the couplers on a 94+ shaft by leaving it mostly still in the van... because as we already know, taking the shaft out of the van is a huge pain!

[timsrv]

The rear coupler is easy. It's the front one that sucks. IMO, on a 2wd Previa I think it would be easier to remove the shaft (once you have it positioned favorable for replacing the front coupler, you might as well remove). On the All Trac the differential & axles inhibit complete removal. On my All-Trac, I replaced couplers from underneath with the shaft still "mostly" in place. I don't remember all the particulars, but I do remember it was somewhat of a PITA. Tim

[maestro123]

That service bulletin was really helpful. Thanks Tim!

[sited faith]

I have changed couplers a half dozen times, at least. Here's my $.02. The original couplings last a long time because of the factory-perfect alignment. All of the rubber mounts compress over time, especially the front motor mounts. Even if you can change those (the right side one is a bear) there are several other rubber mounts. Hence misalignment and short lifespan of SADs coupler replacements. I've just purchased the BMW couplers (discussed elsewhere on this site and at the Yahoo Groups site) for my next go-around. They are designed to withstand full engine torque to the drive wheels and might stand a chance for a long life.

If someone could fabricate a SADs alignment tool and rent or loan it out to enthusiasts, I would be first in line.

Mike H. '97 345k miles (prior '93 268k miles)