Anyone put a 6spd on a 3.5L in a 4th Gen? Of course it bolts right up to the engine, but is there space for it? Mounts? Any custom fabbing neccessary?

 

vslamov (?) supposedly does. The 5M would be more effecient .. IMO

 

Well there's been cases of the 6-speed connected to the VQ30, and that's the same block, so I'd assume there's space.

NMex, I'm not trying to be an @$$, I'm seriously asking you why would the 5-speed be more effecient when attached to a VQ35?

 

Well, the 5spd does get more power to the wheels, but the 6spd is better for highway cruising which I do a lot of.

 

The 5spd is more efficient because it just has fewer moving parts, and that means it transfers the engine's power to the wheels better. Its ratios are virtually the same as the first 5 gears on the 6spd, and same goes for the final drivev, so the 6spd doesn't have any advantage in gearing (except for cruising at highway speeds). The 5spd is lighter than the 6spd too, which of course helps things as well.

Go to www.howstuffworks.com and look up manual transmissions. They'll show you how in a manual transmission, all gears are always connected and always turning -- the gear selector just chooses which one the input shaft is connected to. More gears means more stuff that has to turn in the transmission, and that means more power loss.

 

Thanks for the detailed explanation, I appreciate it. I wasn't aware that all gears were constantly moving. See, you learn something new every day

 

yes i have the 6 speed tranny connected to the vq35. the tranny mount is the only thing that you have to mess with. you see on the 4th gen that are 5 speed, the tranny mount is welded to frame just like the engine mount on the passengers side. so basically it is the same mount on both the passengers side and drivers side. now on the 5.5 gen that have the 6 speed, the mount is different. the mount is bolted to the frame with 2 bolts. so basically what i did was cut the spot welds on the old mount and grind everything down. then i sprayed the bare metal so it wouldnt rust. drilled the holes for the bolts and bolted the mount down to the frame. that is all that is involved. everything else is the same.

now about the 5 speed, yes it is lighter and yes there is less moving parts in it and yes there will be a difference in performance between the two but that difference is going to be so small that to me it wasnt worth putting a 5 speed in. i do alot of highway driving so a 6 speed was a plus for me.

 

Just a quick thought, are there any final drive re-gear kits for the 6-spd? If such a kit was available, might it be more advantageous to use the 6 spd for racing because you'd be able to actually use all the gears?

Personally I do a lot of highway cruising too, so I wouldn't be interested in that...but it was just an idea for overcoming the inefficiency of the 6spd and maybe using a little more of its potential.

 

You can change out the final gear I believe, but that wouldn't be ideal. What would be ideal is if Nissan pulled their head out and made the 6th gear a higher gear and made the rest of the gears closer. 3300rpm in 5th gear in a 5spd @80mph is rediculous. Hell, my 96 altima was geared higher with 3000rpm @80mph in 5th gear.

 

It is kinda sad that my 93 pathy auto w/ overdrive runs lower in top gear than my maxima. But, it's no dog through any of the gears.

 

You can't just throw a 6 speed into a 4th gen and call it a day. Only a few people have done it and they'll all tell you how much of a PITA it really is.

Donate and search, all of these questions have been specifically answered before.


The 6 speed is less efficient than the 'old' 5 speed because it has slightly larger gears and it has 8 pairs of constantly meshing gears as opposed to the old 5 speeds 5 pairs (not including the final drive).