MANUAL SWAP 5SPD OR XTERRA 6SPD?

[PATHFINDER95NI]

The 4spd auto is dying on my '99. I hate the auto and I'd hate to put another in. I found a manual that shows pretty much how to do the swap. I've converted my '95 suburban to an LS/5spd combo, and I've replaced the carpet in my pathfinder so I'm confident I can take this on, especially since there is a manual for the manual conversion available.

A few questions remain:
1 - Will the autos transfer case be used with the manual?
2 - Will the autos driveshaft be used with the manual?
3 - Cant the Xterras 6spd be used if the Pathfinders bellhousing was retained?

Any help would be appreciated and Ill post pics along the way.

Thanks,

Nick

[Slartibartfast]

The transfer case from an auto truck should bolt to the five-speed without issue. The transfer the five-speed comes with is basically the same box apart from a lip under the input shaft seal. Not sure what it's for, haven't heard of anyone running into issues without it. Same driveshafts. I've read the bellhousing and transfer case bolts are longer for the manual than for the auto, so try and get those with the transmission. 

 

I didn't even know there was a six-speed in the second gen X. I would not expect it to bolt up. Different engine, different transfer case. Not sure about the six-speed but I don't think the five-speed has a separate bellhousing. 

[PATHFINDER95NI]

Yeah that’s what I figured. The wording in that manual had me wondering though. I’ll make sure I get those bolts

Yes, second gens had the six speed through their entire run. Sure would be nice to get that in the R50, but I did compare the mounting surfaces of the trannys and they are completely different, so without an adapter plate, there’s no way. It seems like it’d be worth it, I’m not sure why no one has done it yet.

Edited June 8, 2023 by PATHFINDER95NI

[PATHFINDER95NI]

I just ran across this, it’s an interesting read so far. It got me thinking about cutting the two engine mounting sides and welding the 5spd mount to the 6spd body. Of course it brings into question, why not just swap in the entire 2gen Xterra drivetrain? https://www.xterranation.org/index.php?threads/6-speed-swap-aka-project-pipedream.6959/

[Slartibartfast]

Cutting/welding might work if you've got the skills and time to do it right. I wouldn't tackle it myself, but after seeing this guy get away with far worse on a Ferrari engine, I'm sure it's possible.

 

I don't see why the VQ40 wouldn't fit, given they got the VQ35 in there. IIRC it's direct-injected, so you'd need pretty much the whole fuel system out of the X, and the electronics could be a struggle given how interwoven all the electrical systems are on newer stuff. If the transfer case output is on the driver's side, you could get driveshafts made to work with the stock running gear. 

 

 

[hawairish]

On 6/7/2023 at 10:45 AM, PATHFINDER95NI said:

1 - Will the autos transfer case be used with the manual?
2 - Will the autos driveshaft be used with the manual?
3 - Cant the Xterras 6spd be used if the Pathfinders bellhousing was retained?

 

1. Yes.  I run a t-case from an MT Xterra on my AT Pathfinder (04) so can at least confirm the mating pattern.  The lip on the front cover baffled me to; seems it was for seal lubrication since the cavity between the MT and t-case contains gear oil, whereas the AT cavity is dry (there's an output seal on the AT and an input seal on the t-case).  The lack of a lip from an AT unit on an MT seems inconsequential, but it may be the case that those TX10s also ran gear oil instead of ATF.  Nissan used both in the TX10, and considering there'd only be one seal separating gear oil from ATF, you'd probably want to considering flushing out the TX10 to run gear oil.
2. The driveshaft yoke will fit the output shaft all the same, but the real question is if the transmissions are the same length.  The FSM specs driveshaft lengths; as long as the rear (or front) drive shafts between an AT and MT for your model year truck are the same, then it's a pretty safe assumption the MT from a donor will be the same length as your AT.
3. Unless you want to be into things for the long haul, I'd not go this route.  I'd assume nothing bolts up, and everything needs to be brought over; just buy the Xterra.  Otherwise, the regular MT swap shouldn't be difficult.  My buddy converted a 00 Frontier AT I had to be manual; pretty much same exact job you're thinking of.  Keep in mind you'll still need more than just the transmission: clutch pedal, master and slave plumbing/parts, floor panels/covers, center console, etc.  Bypassing the shifter lock-out is trivial, and I don't recall if he had any issues after disconnecting the AT control unit.

[PATHFINDER95NI]

10 hours ago, hawairish said:

 

1. Yes.  I run a t-case from an MT Xterra on my AT Pathfinder (04) so can at least confirm the mating pattern.  The lip on the front cover baffled me to; seems it was for seal lubrication since the cavity between the MT and t-case contains gear oil, whereas the AT cavity is dry (there's an output seal on the AT and an input seal on the t-case).  The lack of a lip from an AT unit on an MT seems inconsequential, but it may be the case that those TX10s also ran gear oil instead of ATF.  Nissan used both in the TX10, and considering there'd only be one seal separating gear oil from ATF, you'd probably want to considering flushing out the TX10 to run gear oil.
2. The driveshaft yoke will fit the output shaft all the same, but the real question is if the transmissions are the same length.  The FSM specs driveshaft lengths; as long as the rear (or front) drive shafts between an AT and MT for your model year truck are the same, then it's a pretty safe assumption the MT from a donor will be the same length as your AT.
3. Unless you want to be into things for the long haul, I'd not go this route.  I'd assume nothing bolts up, and everything needs to be brought over; just buy the Xterra.  Otherwise, the regular MT swap shouldn't be difficult.  My buddy converted a 00 Frontier AT I had to be manual; pretty much same exact job you're thinking of.  Keep in mind you'll still need more than just the transmission: clutch pedal, master and slave plumbing/parts, floor panels/covers, center console, etc.  Bypassing the shifter lock-out is trivial, and I don't recall if he had any issues after disconnecting the AT control unit.

Hey, thanks for taking the time to answer some questions, I appreciate it.

After a bit of reading I did see that it seems that the AT TC will work, and that makes a lot of sense. Using two different TC's would have been pretty costly at the time. I also read that the driveshaft is the same, so that's cool.

I pretty much came to the same conclusion. It was just a passing thought anyway.

 

Now, the next thing Im thinking of is the cruise control. I did a 5spd conversion on my '95 Suburban and the wiring to make the cruise control work, was too intense so I never got the CC working. This manual doesn't cover the cruise control wiring, but I know from working on the Suburban that the CC cancel switch was on both the brake and the clutch. How the heck do I make this work on the Pathfinder?

 

http://overlandtrucks.com/system-f/Transmission Conversion Manual_final.pdf

[hawairish]

On 6/9/2023 at 2:36 PM, PATHFINDER95NI said:

Now, the next thing Im thinking of is the cruise control. I did a 5spd conversion on my '95 Suburban and the wiring to make the cruise control work, was too intense so I never got the CC working. This manual doesn't cover the cruise control wiring, but I know from working on the Suburban that the CC cancel switch was on both the brake and the clutch. How the heck do I make this work on the Pathfinder?

 

http://overlandtrucks.com/system-f/Transmission Conversion Manual_final.pdf

 

Looking at the 99 FSM wiring diagrams for cruise control (a.k.a., Automatic Speed Control Device, ASCD) the difference between the AT and MT isn't much.  Looks like all you'd need to do is replace the Park/Neutral Position Relay with the Clutch Switch, or wire it between the Brake Switch and the Hold Relay and bypass the PNPR.

 

Only other uncertainty is whether there were separate AT and MT ASCD modules, and whether disconnecting the AT TCM affects the signal on Pin 12.  My hunch is that the modules were the same and disconnecting the TCM won't be a problem.

 

 

 

 

[hawairish]

On 6/9/2023 at 2:36 PM, PATHFINDER95NI said:

http://overlandtrucks.com/system-f/Transmission Conversion Manual_final.pdf

 

And I didn't read through all this, but that's very awesome that it exists!  I'd love to MT swap my 04, but it seems extremely difficult to even acquire all the necessary parts.  MTs appeared to be far more common in Canada; donors are practically nonexistent in the US.

[Slartibartfast]

NissanPartsDeal lists three ASCD computers that'll fit a '99 (18930-0W000, 10/'95-12/'98; 18930-1W200, 7/'97-12/'98; 18930-2W600, 12/'98-01/'00), but all three are listed for MT and AT. So, yeah, swap the auto trans shifter safety for a clutch safety and you should be golden.

I'll bet pin 12 is how the ASCD tells the TCM to shift up or down. Might be straight-up commanding the TCM to shift, might just be feeding it the target speed so it can make up its own mind. I assume the ASCD doesn't expect a reply and so doesn't know/care if there's a TCM present or not. 

 

I remember someone came up with a rail shifter kit for the RE4R01A, but they were using it in a W/D21. I can only imagine how upset the VQ R50's electrical system would get if something else was controlling the slushbox.

[PATHFINDER95NI]

Hawairish

Hey man, thanks so much for replying, I really appreciate it. Posting those schematics is a huge help. I looked for the FSM and where it once was, its gone now. I think Nissan made them take it down or something. I bought one on Ebay, but the guy is taking his sweet time to ship it.

 

Sorry about the simple questions, but I want to be absolutely sure before I dive into this. When you write that I need to " replace the Park/Neutral Position Relay with the Clutch Switch, or wire it between the Brake Switch and the Hold Relay and bypass the PNPR". Are you explaining it like the manual is here on page 14 from the manual? 

 

Yes, as I was reading up on this I noticed in a few threads that the 3.5's had a power valve on them for the automatic equipped R50s. To correctly convert a 3.5 equipped R50, you have to replace the upper and lower intakes, amongst other items.

 

Once Im done with this, Ill gladly create an addendum to this manual to help any other R50 owners that are looking to convert their autos.

[PATHFINDER95NI]

16 hours ago, Slartibartfast said:

NissanPartsDeal lists three ASCD computers that'll fit a '99 (18930-0W000, 10/'95-12/'98; 18930-1W200, 7/'97-12/'98; 18930-2W600, 12/'98-01/'00), but all three are listed for MT and AT. So, yeah, swap the auto trans shifter safety for a clutch safety and you should be golden.

I'll bet pin 12 is how the ASCD tells the TCM to shift up or down. Might be straight-up commanding the TCM to shift, might just be feeding it the target speed so it can make up its own mind. I assume the ASCD doesn't expect a reply and so doesn't know/care if there's a TCM present or not. 

 

I remember someone came up with a rail shifter kit for the RE4R01A, but they were using it in a W/D21. I can only imagine how upset the VQ R50's electrical system would get if something else was controlling the slushbox.

Thats some good looking out there, thanks for doing that. Ill confirm my ASCD is the first part number, but I think you are correct. So that clutch safety would just be pulled from the donor vehicle and two wires ran to the PNSS relay spot right? Just put the two wires into the corresponding pin location?

 

If that is the case, would pin 18 on the TCM be telling the gauge pack to turn on the cruise light when cruise is enabled? Do I need to worry about that or does the ASCD also do that with its pin 13?

 

A rail shifter? Huh, yeah Im sure the electronics would go haywire if it was noticing a different input.

 

Thanks again for your help.

[hawairish]

The FSMs have been back up for a while now.  They were taken down the other year, but that's all been sorted.  The screenshots I posted were from accessing the 99 FSM that day.  It does appear that conversion doc is now no longer available, though.

 

Since that other guide already shows how to bypass the P/N Relay in the box (you're basically just jumping the connections), the easier route to incorporate the clutch switch would just be to put it on the same circuit as the brake switch above the pedals.  The ASCD module is just checking for any opening on the circuit, so if you add another switch there it won't know the difference.

 

As for that relay bypass, if you want to keep the installation clean (and safe), you could pop open that relay and solder the connectors in there instead of just jamming wires into the open relay port in the fuse panel.  Either way, make sure the wire is sufficient gauge, otherwise you're just putting a filament in place.  Other way is to just make short jumper wires using crimp-on terminals.

 

The FSM also confirms the following:

• Pin 18 is the signal to the Cruise lamp on the dash.  The TCM also uses this as an input signal/switch that CC is engaged.
• Pin 12 is a signal to the TCM to turn off overdrive.  This specifically occurs when the vehicle speed drops to 5 mph or more below the set speed, allowing the TCM to drop the transmission out of OD.  Once the truck is 2 mph over the set speed, then the signal is turned off and OD use restored.  The vehicle speed is detected by input from the gauge cluster ("Unified Meter Control Unit") on Pin 7, and speed is adjusted by the ASCD's control over the ASCD pump (Pins 8, 9, 10, and 14)

That said, removing the TCM should have no impact on cruise usage, and wiring up the switch looks super simple.  I'd bet if you can get the under dash wiring for the switch, you could just pop the terminals out of the harness and make it look like it was always there.

 

For reference, you can find this info on EL-163 in the 99 FSM Electrical System.  The first few pages cover the System Description, Schematics (shown above), and the Wiring Diagrams.