Will My Current Driveshaft Fit?
Unless your already running a T56 (like an older LS T56) or you have a F-body camaro then likely you will need a new driveshaft as the length of your current transmission is going to be different than the T56 you are swapping in.
Driveshaft length is VERY important. You need to not be too long, and not too short. A driveshaft that is too long will PUSH on the rear of the gearset in the trans, creating an unnatural load which can wear out the bearings inside the transmission and wear out gears prematurely as well. A driveshaft that is too short will not get proper engagement of the slip yoke, and will cause you to wear out the tailcase bushing and cause yoke failure as well.
On IRS applications, where the differential is not moving up and down... I like to see a T56 yoke where the about 1/4-1/2" of the smooth barrel is showing. On a solid axle, when the rear suspension is drooped, you can have a bit more of the barrel showing, as this should push into the trans when the car is at ride height.
Here is a picture of what I typically like to see yoke engagement wise (on IRS suspension).
Swapping to 8.8 Rear?
Similar to a transmission swap, where the transmission length changes, a differential is also going to be different length. So in most situations when swapping to the 8.8 rear you will need a longer driveshaft. On applications like the MKIV Supra/SC300/IS300 etc the driveshaft will need to be roughly 2" longer.
So for example, if you have a MKIV supra, and you have my aluminum driveshaft for a stock 200mm rear (part# TOSH56F-A) then you will need the 8.8 specific part# which is TOSH56F-A-8.8
Measuring For New Driveshafts
One of the most common questions I get is how to measure for your driveshaft.
The way I prefer you to do this is to take the end of the tape measure, and put it on the face of your rear differential flange, then pull the tape up to the transmission, and take a picture so I can verify the measurement.
You want the total measurement to be from the diff flange face to the base of the seal (or back of the tailcase) on the T56. You are NOT measuring to the tip of the seal, NOT measuring to the back of the output shaft, but to the back of the tailcase where the seal base is held in place.
So your measurement picture should look like this
The seal on the T56's has a "boot" which protudes backwards, this is not where the seal actually resides, so you need to measure from the base of the seal.
For those of you with a flange/flat yoke on your diff, this is what you will be measuring
If you have a flat output flange on both your transmission and diff, this is what you are measuring
If you have a pinion flange that uses u-bolts or straps (like a 9" FORD) then you will be measuring like so
To measure a pinion flange for dimensions, here is how you do that. If you aren't sure what size u-joint you have, measure as the pinion yoke as shown here
Be very careful and accurate with these measurements as the size changes in increments of 1/16" (1-1/16" | 1-1/8" | 1-3/16").... And let your builder know if you have locating tabs (as shown) or if your yoke uses an inside clip
If you have a flat flange, we may need a flange measurement to identify the correct one, see the diagrams below for how to measure 3-Bolt, 4-Bolt and 6-Bolt Flange patterns. NOTE: ANY RUBBER GUIBO COUPLERS MUST BE REMOVED BEFORE MEASURING
3-bolt type
