# VLSD Rearend Question?

**URL:** <https://forums.speedlife.net/t/vlsd-rearend-question/81426>\
**Category:** SON240sx Automotive\
**Created:** [August 12, 2004, 12:20pm UTC](https://forums.speedlife.net/t/vlsd-rearend-question/81426 "2004-08-12T12:20:16Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![papapump](https://avatars.discourse-cdn.com/v4/letter/p/8dc957/32.png) [@papapump](https://forums.speedlife.net/u/papapump)\
**Post date:** [August 12, 2004, 12:20pm UTC](https://forums.speedlife.net/t/vlsd-rearend-question/81426/1 "2004-08-12T12:20:16Z")

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I have a 1990 240sx Fastback 5 speed and I want to do a vlsd rearend swap. I was told there are three different gear ratios and a speed sensor. What ratio should I choose, and is the speed sensor only for automatics?

Any input would be greatly appreciated.

P.S. I heard I will also need a new driveshaft, is that true?

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**Author:** ![mr200](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/mr200/32/5495_2.png) [@mr200](https://forums.speedlife.net/u/mr200)\
**Post date:** [August 12, 2004, 1:22pm UTC](https://forums.speedlife.net/t/vlsd-rearend-question/81426/2 "2004-08-12T13:22:25Z")

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gear ratios are ratios.

the 4.10 gears that come stock in your 240 multiply the torque of your engine 4.1 times.

This is a steep gear. This is a gear set that muscle cars tend to stick to. Any higher (numerically) will kill your top end.

It’s a trade off.

Lower numerical gear sets will give you more top end, but hurt your torque.

The 240s came with 4.10s to make it accelerate with a fairly anemic engine.

So if your motor is stock … keep the 4.10 gears, and just swap a VLSD carrier in.

If you have a decently worked motor, the 3.7s out of a 300ZX would be a nice match.

If you have more power, and are sick of shifting gears every second, the 3.5s out of a Q45 would be nice.

But you don’t need to swap the entire pumpkin, just the carrier.