Anyone with 4.08 gears and 7AT?
 

Looking for help on the 4.08 gears for the 7AT

I know you need a 3.6 from the manual transmission (g37 or 370z if I recall correctly) and then the 4.08 gears.

Can just leaving the 3.6 from the manual be done, without using the 4.08 or will it not work?

Please post your experiences. Again, this is for the 7AT and I know that cruise control will be lost.

Man Alfredo your ambitious with your modding brother. I like your style

Subbed for results/answers.

I'm not sure but you may need a whole diff from a manual transmission and a MT drive shift to make it work.

Check out this thread

https://www.myg37.com/forums/engine-...ml#post3820810

lol thanks I guess.

Thanks! Been reading and trying to figure it out. Apparently the 5AT g37 has the 3.69 FD. Still trying to understand if it would be a bolt on or swap into the 7AT, while still maintaining the cruise control.

From what I have read, the 4.08 is too much gear for the 7at. Basically makes 1st and 2nd gears useless, the 3.69 on the other hand would be a nice upgrade. I think all you would need to do is change the flange on the diff for the 7at and your good to go. As far as the cruise control, I think you need to get a tune to have that adjusted but don't quote me on that. Whatever swap you decide on, please report back to this thread to give us your impressions.

Edit: if you are getting the rear end from a 5at 08 g37,it may be just a bolt on and go, I'm not sure if the flanges where the driveshaft meets the diff are the same.

I agree on the 4.08 being too much. That 3.69 gear would be much better. I dont know much about gearing so still searching on what would be required to swap.

I've been thinking about the 3.69 for my Sport. Seems it's pretty easy to swap, just finding a 3.69 MT diff that isn't full of wear is the issue.
From what I searched all you need is the Diff, & either swap the flange or get the rear section of the MT drive shaft & new bushings.

Do you know if it would be the same as using the 3.69 from a 5AT G37?

Not sure....
I actually just got a 2012 6MT diff off Ebay. Local to me too.

Search for SharpByCoop and see how he did it. He had a 5at however he got many responses from doing it.

Alfredo,
I have all the parts needed in various hidden spots around the house. I have a 12 coupe and the driveshaft is one piece and nor bolted so I had to buy two 08 shafts. The front from a 5AT and the rear half from a manual. I also went ahead and got a whiteline bushing kit. The only other necessary item is for me to flash Uprev so that after the installation I can eliminate the P0500 code. I'm guessing I'll have it done in the next month if not sooner. I got info from posts by N'beond , Coop, Sam and a lot of experiences posted on the 370 forum. The cruise control issue can be solved. I also have a thread that I plan to post my review on.

Im still trying to figure out all the terms about the differential. I know what the flange, differential, VLSD and FD are but don't know much about how it all comes together.

Thanks. Will do.

I subbed to your thread. Thanks.
Also rereading various threads that could be helpful.

Should also look into changing your differential bushings while that pumpkin is out... No more wheel hop...

Yep. Already read about the whiteline bushings.

OP, i believe you have a one piece ds. should you buy a diff from an 08 or a manual G, be careful of what you'll need to get. it may be as simple as a yoke or locating an entire ds and then piecing something together. That's what solidus has done, and what I am doing. I didn't get enough even tho solidus warned me... :eek3: I ended up getting a 2012 diff from a 370z with VLSD and an 09 ds from a MT sedan. will still need to piece that damn thing together... :52:

Guess you never rode in a car with 4.08 gears!!
they are not to much at all if you know how to drive and once you get use to them you will be glad you put them in.. I have had them for over a year now and love them I wouldn't put any other gear in but 4.08..

yes you are correct you need the differential from a Manual..

if you want to use the 3.69 you will have no issues..the reason you need the Manual differential is because the housing for it is for the bigger gears of the 4.08..

you do not need a half drive shaft off of a Manual.. they took the flange off of my differential for the Auto and put it on the Manual differential with the 4.08 gears in it..i have had 0 issues since install over a year ago..

sounds like a PITA tbh..I'm not worried about the process and parts, but what worries me is starting the install/process and then having to leave the car collecting dust at a workshop, while some other part that I would need to arrive or even worse, having to look around different websites and junkers for the part to be available.

why would you have to leave the car at the shop if you order the differential you have all the time in the world to work on it until you get ready to install it on your car.

this is all you need to get stated and finished

http://www.ebay.com/itm/03-04-05-06-07-08-Nissan-350Z-Locking-LSD-Differential-3-538-Ratio-36801-/281444050051?pt=Motors_Car_Truck_Parts_Accessories&hash=item41875f6483&vxp=mtr

Differential Final Drive Gears Ring and Pinion 3.9, 4.08, 4.36

chuckie,

should the op go with 4.08's, you're correct regarding the yoke in the rear, but if he purchases a manual diff and uses it as is, 3.692 and hopefully VLSD, their are differences that just a yoke change will not fix.
https://www.myg37.com/forums/engine-...-on-awd-g.html

check this thread out...

But what about the install process? I was told that a driveshaft from a 6MT sedan (in my case since I have a sedan) was also needed.

op, since you're going to 4.08, get a manual transmission rear diff with VLSD and have the gears installed. doing this yourself isn't an option unless you have all the tools and know how. Once this is done, the yoke from your original diff should be used as chuckie stated. There will not be problems... cost will be gears, oil, diff rebuild kit, shims and labor for the install. Speak with mechanics and find someone you're comfortable with....

Going off Coops install I decided to use the Manual shaft because the 6MT diff doesn't have the centering pinion and putting an AT flange there without a means of positively centering it is kinda winging it , you may get it right but you may not. With an MT flange there's no doubt. It's been done yes but if Coop felt the need to change it regardless of power I chose to just do mine that way from the beginning.

you do not need a drive shaft I don't know why everyone thinks you do.. mine was done without replacing a drive shaft only the flang was changed...if you look at the ebay listing I sent you you will see that there is no centering shaft I bought the rear differential that did not have one..mine was from a 2008 g35..
look here is a pic of the flange on a 350z see how there is no centering shaft..

You're right there is no centering pinion on the 6MT because the 6MT uses a centering ring on the surface of the driveshaft flange. The AT flange does not have this and you rely on the rubber coupling to stabilize without the benefit of a universal joint that's found only on the MT driveshaft. It can be done for sure but I personally like to benefit from the experience of others and when Coop did his initial install it didn't take long for him to see the light.

You're right there is no centering pinion on the 6MT because the 6MT uses a centering ring on the surface of the driveshaft flange. The AT flange does not have this and you rely on the rubber coupling to stabilize without the benefit of a universal joint that's found only on the MT driveshaft. It can be done for sure but I personally like to benefit from the experience of others and when Coop did his initial install it didn't take long for him to see the light.

I won't be doing this myself as I don't even understand what is being said here lol. I will talk later with a mechanic and show him this thread to see if he understands better than me about what parts are required, optional, recommended, etc.

Alfredo you can simply swap the flanges and run the 3 point AT differential but when Coop did it he had some vibration probably due to alignment of the driveshaft at the flange union. He opted to change the rear half of his driveshaft to the MT and it was all good. Not necessary but the safest bet outside a custom carbon shaft. On a side note I spoke with Mark at PST today about making me a Carbon shaft. He told me he was using the same slip yoke on the MT and AT shafts as far as he knew. I'm going to pull all mine tomorrow to see the spline count for all interested.

Bumping this thread.

I'm a bit closer to doing this mod and just making a final checklist for things to buy.

For now, I have on my ebay watch list a 6MT diff from a 10 G37S Sedan, which means LSD and 3.692 gears. Also planning on getting the Whiteline differential bushings.

If I interpreted the information correctly, I could just buy these parts and let my mechanic do the rest?

What about the flange where the driveshaft meets the diff? Is it a direct bolt on? Maybe do sway bars while your back there.

I'm not sure. That's why I'm asking :p

I might do sway bars later on, but no need to it with this. It's a pretty easy install that I can DIY.

Just do the flange swap and call it a day. Several other members had this done and have zero issues. One had issues but he was boosted and was putting down over 500wtq. I personally have had zero issues with my 3.90 swap.

Thanks! Good to know. I'll be doing the 3.6 swap with the whiteline bushings for now. Hopefully very soon.