th400 swap ?s

[Jason Flaty]

any of you guys swapped out your 60e to th400? got the tranny in with bmr crossmember and relocation for torque arm. wondered what major problems you ran into doing this swap? how did you wire your neutral safety switch and how much shorter did you have to make your driveshaft?



jason flaty

95ta vortech t-trim, ported lt1 heads custom cam smoked 4l60e(making room for th400 built by coan transmission) 373s nitto drag radials

[Injuneer]

I did a T56->TH400 swap. You need to measure everything after you get it together, to determine the exact driveshaft length. You can't guess and you can't rely on what someone else did. After you measure it, let me know the exact length you need. I have a Mark Williams 3" chrome moly DS with 1350 solid u-joints, and a TH400 billet slider. Cost over $600. I can let it go for $400. I needed to change to an even shorter DS.... see below.

You will need a shifter. I used the B&M Pro-Ratchet. It comes with a neutral safety switch and a backup light switch. The old wires simply get connected to the new shifter.

There are several different tailshaft lengths on the TH400. I've seen some people claim they were able to reslot the stock M6 tranny cross-member to mount the TH400. On mine, we had to reinforce and extend the stock M6 cross-member.

I don't know the details of the actual TH400 that ended up in the car. I know absolutely NOTHING about auto trannies, other than the fact that I needed one. The shop that built my stroker had a reliable trans builder nearby. They worked together on the details.

If you plan to street drive the car, you're going to have to like the high rev's you get at highway cruising speeds, because of not having the O/D gear. I ended up adding a Gear Vendors O/D unit. Engine was pulling almost 4,000RPM at 70MPH with my 4.11 gears and 315/35-17 street tires. The GV dropped it closer to 3,000RPM. GV = shorter DS.

I also run a SFI-rated flex plate, a JW UltraBell, and an ATI trans shield. All are required by NHRA depending on how quick you plan to run.