yea thats what i suspected too. I will have to check.
Are those sensors expensive?

No idea, unless you installed it yourself take it back to the shop and make them replace it

About $150-$200 each for the parts. I think I paid just under $200 when I replaced mine.

alright, i have done some research in my decision of which ratio to go. here is the data ive put together. all of this data is with the manual transmission with sport package tires. hopefully this helps someone else out in the future as well

Stock redlines.
1st- 42mph
2nd-69
3rd-99
4th-126
5th-160
6th-202

3.9 final drive
1st-40
2nd-65
3rd-93
4th-119
5th-152
6th-191

4.08 final drive
1st-38
2nd-62
3rd-89
4th-114
5th-145
6th-183

4.36 final drive
1st-36
2nd-58
3rd-84
4th-107
5th-136
6th-171

if you want to know what rpm you would be at in any gear at any mph with any final drive just let me know and i can figure that out too.

here is the rpm at 70mph which i figure is highway cruising speed for most people

Stock FD- 2591rpm
3.9 FD- 2738 rpm
4.08 FD- 2864 rpm
4.36 FD- 3061 rpm

I would honestly just go with 4.08. I think that 4.36 is a bit much, unless you plan on making your Z a dedicated track car. I remember when I drove my 350z with 4.08 rear from WA to TX, my RPM's were getting way up there at cruising speed. I think at 75mph to 80mph I was almost at 4k rpm. It was basically like driving in 5th gear the whole way down there.

To fully utilize the 4.36 FD on the strip you're going to need slix, ECU reflash for a rev limiter @ or > 8,000RPM, and a Nismo oil pump. For the week end ST racer/garage queen, these gears are fun as hell and I wouldn't go to anything higher since the VQ don't make any torque. If you daily drive your Z and are slightly concerned w/gas mileage, then you better go for the 4.08 FD.

I finally just installed my 4.36 2 weeks ago, and wanted to give my input so far on them. Srm is nonexistent if you are driving spiritedly/tracking. If you are cruising under 4k there are no issues though.
The lower gears are soo much fun now, with my 305 pss I couldn't chirp the tires going into 2nd before the swap and now I feel like I could spin out into a ditch going into 2nd if I'm not careful.the difference is astounding. I live a few miles away from a dragstrip, raced my buddies 5.0 mustang before and after the swap. Before he murdered me by 5 car lengths and now we are neck and neck with him starting to pull away by the end of the strip.
Overall, I would not recommend the 4.36 over the 4.08 to anyone who cares about fuel economy or to anyone who cares about srm. But I personally have been known to do "because racecar" mods as evidenced by all my solid bushings and now this, and I love them. Best mod ever

FYI, with the new phase 2 rom from Ecutek, you should be able to get your SRM back.

Also a quick question, just out of curiosity, how short is 1st? Is it basically get off the line and shift in to 2nd?

I just bought uprev last fall so maybe this upcoming fall I'll switch to ecutek, I have seen some awesome things they're doing.
And yes, first is very quick, I find myself at 3k RPM halfway through intersections where I had to stop for red lights

Did you change LSD with the gear change or keep stock?

Stock vlsd. Couldn't stomach dropping another grand or so, especially since I don't track the car. The vlsd paired with nice tires are enough for my drag and spirited driving needs.

Looks like you and I have the same needs. I too am having a hard time stomaching the extra grand + . if stock vlsd can handle the gear swap that is great news. That mean I could get the swap done much sooner than I expected. Thanks for the info. Keep us posted on anything good or bad. Congrats on the swap.

Make sure to get some solid or poly differential bushings while you do the swap. That'll make a world's difference in helping you get traction on launches

That's Pretty Good-Maizenblue; i had previously done the same math w/my 7speed auto.
didn't know some of these guy's were pulling their Z's up to redline in Overdrive?

Nice review and congrats on the swap!

This would put the 7AT in full beast mode . :)