6 speed swap AKA Project Pipedream

[Prime]

Gen 1 5-speed manual transmission. PN: FS5R30A

Gen 2 6-speed manual transmission. PN: FS6R31A

Those part numbers are really close.

Possible interchangeability? Discuss.

 

[drbandkgb]

hmmmm....
Whats your idea with this? Seems like the Gen 1 is pretty under powered as is so what would be the benefit of the 6th gear?

 

[Prime]

It's not just the 6th gear. It's all the other ratios. Every gear is shorter. Except for the overdrive. Which is longer. But only by a little bit. I think it'd make the driveability go way up.

 

[drbandkgb]

Could..
Im guessing shorter throws.. You would need to either use the current shifter or enjoy that short stick

 

[Prime]

I would have no problem with that. But there's so much research to be done. Shifter is the least of my concerns. Mainly input shaft/clutch and output to transfer case. Those are the big ones.

 

[Prime]

What I really need is good photos of the input and output sides of the transmission with it removed from the truck. Which, unsurprisingly, is proving difficult to find.

My #1 concern is that the bell housing is manufactured as part of the transmission. So something would have to be done to address that issue.

 

[Prime]

The 6 speed ratios:


. . . . . . . . . . . 1st. . . . 2nd. . 3rd. 4th. . . 5th6th
FS5R30A 3.5802.0771.3601.00 00.811

FS6R31A 4.368 2.5181.743 1.2831.00 00.769

Yeah. Bettah.

 

[caseycamby]

This is interesting. I'm looking forward to info on this.

 

[Dbrown016]

Also intersted in this topic. my 5th gear is at 3.5k at 70 mph and I constantly say I need a 6th gear to bring it down to 2k. Plus my first gear is like non existent because I'm in it for like 2 seconds.

 

[Prime]

This swap would result in a slightly lower interstate RPM. but not too much.

The lower gears will actually be a lot quicker because of the higher gear ratios.

 

[Jbat]

Really what you need to find out is diameter of 6 spd clutch vs 5 spd clutch and diameter of both flywheels. You also need to find out the diameter of shaft where it rides on the pilot bearing in the flywheel. You might get lucky and be able to use a 1st gen 5spd flywheel with 6spd clutch. Then the only thing you have to worry about is bellhousing bolt pattern. The input shaft actually engaged the clutch so that's why the clutch/flywheel compatability is what I would be looking at first

 

[Prime]

Yeah. I've considered all that. I've been digging and trying to find specs for two days now. There isn't a lot of information out there.

I'm sure there's something different about the input shaft. As the aftermarket clutch kits for both trucks differ by one number as well. But it could also be clutch diameter.

That being said, clutches can be custom made for diameter and drive spline dimensions. It's another question entirely weather the input shaft will go into the VG pilot bearing or conversely if the VQ pilot bearing will fit into the VG crank.

This is why I need shop space. I'd just buy one of each from a junk yard and dive into them.

 

[Prime]

Provided the pilot bearings were in some way interchangeable, and the clutch fit under the pressure plate for the VG flywheel, then yeah, it's just the bolt pattern.

Of course the output shaft is a whole different can of worms.

 

[Prime]

So here's the bolt patterns on the bell housings.

6-Speed:

5- Speed

So there's that problem to overcome as well.

 

[Prime]

Further reading. So apparently the "bellhousing" as I know it from american cars is not the same here.

I'm used to a sealed transmission unit, with a bolt on bellhousing that bolts to the engine. Making this change easy.

On the Nissan, the bellhousing actually holds the gear train. so the part pictured here

is the bellhousing. and the actual gear train of the transmission lives in the narrowed section of that.

The above picture is from Nico Club. A guy pulled the guts from a Pathy FS5R30A and swapped the gear train into a KA24 bell housing.

That being said, the gear train can be removed from this housing.

as shown in the FSM:

So that gives me an idea. Can I pull the gear train from the FS6R31A and put it into the casing of the FS5R30A?

I NEED TWO TRANSMISSIONS AND SPACE TO PLAY WITH THEM!

 

[Prime]

And apparently the Overdrive gear train lives in the same section of the housing that the shifter bolts to. Which sandwiches between the main case / bellhousing and the transfer case.

 

[Jbat]

And apparently the Overdrive gear train lives in the same section of the housing that the shifter bolts to. Which sandwiches between the main case / bellhousing and the transfer case.

I would swap the 6spd tranny and everything bolted behind it including the t-case. The flywheel bolt pattern can easily be overcome with an adapter and a flywheel spacer on the crank. With that you could actually make the spacer custom to hold both the 6spd flywheel and the 6spd pilot bearing. Just another adapter of sorts

 

[Prime]

Which increases the length of the gear box and would affect shifter location. Not to mention the selector on my transfer case is manual. Not electronic as the 2nd gen case.

 

[Prime]

Also, in doing this I'd more likely try to swap to the earlier Pathy transfer case that has a thicker chain and available crawler gears.

 

[Nd4SpdSe]

Hows the Pathy T-Case different for crawler gears? I got a T-Case from an 01 Frontier and I've read is the same deal/same thing.

 

[Nd4SpdSe]

http://www.twinturbo.net/net/viewmsg.aspx?forum=technical&msg_id=1000850

 

[Prime]

http://www.twinturbo.net/net/viewmsg.aspx?forum=technical&msg_id=1000850

That's interesting.

 

[ryandavenport]

That's interesting.

http://www.thenewx.org/forum/showthread.php?t=160042

Found this for you


Sent from my iPhone using Tapatalk

 

[Prime]

Heh. Thanks. If only I had the room to mess with it.

 

[Prime]

Always good to see new ideas and folks thinking outside the box.

Is this "possible", sure, everything is with enough money and knowledge.
Is it practical, that is up to the individual doing it. My opinion, not in the least. I think you would be time and money ahead to just swap the motor with the tranny if you really want that 6th gear. I honestly think it would be cheaper that way then just the tranny.

As for adapting a TX-10 to a Next Gen tranny, several have looked into it, and come to the conclusion that the cost outweighs the benefit, by A LOT. I'm not talking one-off's with this one either. If someone could effectively make a kit to swap the two, think of the market for it.....and that still wasn't enough to justify it.

Now, there are folks looking into crawler gears for the next gens, so gearing might just be available by the time you swap everything, so keeping the T-case isn't as bad then. So that's a plus.

Good luck, and keep on thinking outside the box.

Cheers,
JP

So I would need the 2nd gen transfer case. Which means figuring out how to throw the relays for the different modes. And replacing the manual linkage with an electronic setup.

 

[Prime]

Hows the Pathy T-Case different for crawler gears? I got a T-Case from an 01 Frontier and I've read is the same deal/same thing.

It was my understanding that the older Pathy T-case was different in a few ways. One being the larger drive chain, the other being availability of gears. If I'm wrong about the, I'm wrong.

 

[hfunkhouser]

Just FYI, that 2nd gen website has a member selling a complete 6speed with all the trim etc for 850....just so you know.

 

[Prime]

Yeah, I've already been linked to it. If I had the room, I'd jump on it.

 

[J Everett]

Always good to see new ideas and folks thinking outside the box.

Is this "possible", sure, everything is with enough money and knowledge.
Is it practical, that is up to the individual doing it. My opinion, not in the least. I think you would be time and money ahead to just swap the motor with the tranny if you really want that 6th gear. I honestly think it would be cheaper that way then just the tranny.

As for adapting a TX-10 to a Next Gen tranny, several have looked into it, and come to the conclusion that the cost outweighs the benefit, by A LOT. I'm not talking one-off's with this one either. If someone could effectively make a kit to swap the two, think of the market for it.....and that still wasn't enough to justify it.

Now, there are folks looking into crawler gears for the next gens, so gearing might just be available by the time you swap everything, so keeping the T-case isn't as bad then. So that's a plus.

Good luck, and keep on thinking outside the box.

Cheers,
JP

Tell me more! Though if it's not relevant to this thread, maybe just PM a link to another thread? I don't want to hijack Prime's thread any further than I am with this post.

 

[Mirage]

Its would be a complicated swap, there are adapter plates to get the 6 speed to bolt up to other nissan motors, but you would be coming up with your own for the VG33. The measurements to center the input shaft have to be precise in order not to cause bearing failure in the transmission (and/or clutch/flywheel issues). Then do you use a thick bolt on type spacer and with a flywheel spacer, or do you machine the trans case to take the thickness off from the spacer?. Then if the top mount shifter hole (from the 2nd gen trucks) isn't close you gotta deal with locating the shifter (an issue on S chassis cars with a 6 speed swap because the car trans use a cast aluminum v to locate the shifter off the tail), this becomes more an issue if you space the trans back with an adapter plate as well.

To me it isn't worth it, like already stated, you would be better served to swap in a VG40 with the 6 speed and transfer case already attached. If you had the time and space to play you could frankenstein the FS5R30A with different gear ratios from different trans etc. The 96+ Japanese 300ZX TT (made until '99 in japan, we stopped getting them in '96) also have more improved parts in the transmission, I believe they have better synchros (triple cone on 1 and 2 and double cone all the way into 5th IIRC)

 

[Prime]

Party pooper.

Heh.

Some of those questions can be answered with measuring. I really want to get both side by side so I can do a spot on comparison.

Maybe I'll have room in the next house.

 

[Prime]

Honestly, having the extra gear wouldn't be my big plus. It'd be having the ratios of the 6 in the 5. Specifically 1st, 2nd, and 5th be closer to 1st, 2nd, and 6th.

 

[Prime]

Maybe instead I should be looking at other gear ratio options that the FS5R30A came in.

 

[Mirage]

I had looked at ratio's before, I don't remember specifics, I'll try and do some research if I get a free moment but i'll spout off some chassis that I know of/think used the big 5 speed transmission like those in our trucks to get you started. The obvious Z32 (TT and NA are the same, I have a NA trans behind my VH45) Early R32 GT-R (AWD of course), R33/R34 GTS-T (the RWD RB25DET powered cars, not the GT-R), Late Z31 turbo (early turbos possibly too, I think early NA's had a T5 variant), V6 WD21 Pathfinders and Hardbodys. I'm sure i'm missing some, I know there are some rare/obscure JDM only cars that had them as well like the Cefiro but that doesn't help too much.

 

[Prime]

The only thing I can find that would be an improvement is that the z32 FS5R30A had a 0.711 overdrive. All the other ratios are lower. Which would suck.