Shifting questions

[GTSBoy]

It's OK. When it dies, you just put a manual in.

[Dose Pipe Sutututu]

Let me hear it, Samsonas 

[DRoc81]

  On 02/04/2025 at 11:01 AM, GTSBoy said:

It's OK. When it dies, you just put a manual in.

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That'll be most likely down the road...  LOL

 

[DRoc81]

  On 02/04/2025 at 9:02 AM, dbm7 said:

...just a note of warning, you shouldn't drive it about with the TCU in limp mode with only 3rd gear available ~ apart from the fact you end up sheering the ATF at the torque converter interface, the high clutch in these isn't especially the strongest, particularly bolted to the RB25DE mill...which is likely a 4AX01 box with lighter duty high clutch (the RB25DET got the bigger high clutch)...be careful out there...

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Kinda something I have been thinking about.  To be honest, we bought it already driving like that.  So there's no telling how long it actually has been driving like this.  Hopefully damage is too bad when we drop the pan.  

I am having a hard time finding a site that sells the solenoid for the 5 speed auto, do you have any suggestions?

[joshuaho96]

  On 02/04/2025 at 2:54 PM, DRoc81 said:

Kinda something I have been thinking about.  To be honest, we bought it already driving like that.  So there's no telling how long it actually has been driving like this.  Hopefully damage is too bad when we drop the pan.  

I am having a hard time finding a site that sells the solenoid for the 5 speed auto, do you have any suggestions?

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RE5R01A is the transmission. Didn't realize they had a 5 speed for the NA cars but for some reason the turbo engines stuck to 4 speeds. Looks like the solenoid block is still available from Nissan directly at a somewhat reasonable price: 31940-60X01 https://www.amayama.com/en/genuine-catalogs/epc/nissan-japan/skyline/er33/6568-rb25de/trans/317

I would move sooner on this than later. The moment the de minimis exception for Japan goes away expect to be paying 25% tariffs even for stuff like this.

[dbm7]

  On 02/04/2025 at 10:44 PM, joshuaho96 said:

RE5R01A is the transmission. Didn't realize they had a 5 speed for the NA cars but for some reason the turbo engines stuck to 4 speeds. Looks like the solenoid block is still available from Nissan directly at a somewhat reasonable price: 31940-60X01 https://www.amayama.com/en/genuine-catalogs/epc/nissan-japan/skyline/er33/6568-rb25de/trans/317

I would move sooner on this than later. The moment the de minimis exception for Japan goes away expect to be paying 25% tariffs even for stuff like this.

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Ahh... it's an early RE5R01A box, that means the pinouts I gave are wrong (they were for the RE4R01A 4-speed box)... I'll have to dig around in my docs to see if I've got that schematic (they used the same gearbox plug, with the vacant pin wired to the direct drive clutch solenoid)...prolly hidden away in a supplement somewhere...

...there were 3 variants of the RE5R01A ~ this early schema was what we called the 'dumb' 5 speed ; it's what jatco called a 'medium duty' box, with torque holding up roughly ~200ft/lbs or so, which was good for NA from RB20/25DE and up to around VG30 output spec. With the RB25DET (and VG33/35 mills), the only options they had was the 4-speed 4AX00 box, which had been beefed up to handle the extra torque (primarily for the VG35, but it also suited the RB25DET mill and others)...and the RE4R03 box in large 4WDs a lot of the time...

...the next variant of 5-speed was redesigned, stronger, and 'smart'...first ones had external TCU with internal (on valvebody) Shift Control Unit, pressure switches, and 2 x TSS...and the last ones had internal TCU+SCU setup, with CANbus control etc etc.

@DRoc81 On the RHS of the box towards the rear, there should be a stamped silver ID tag -- what's the model number?

Oh...and with the early 5-speeds, the torque converter control solenoid assembly should be replaced as well (31940-60X00)...it's a bit Murphy's Law ....if one has failed, bet on the rest not being far behind ...

[GTSBoy]

  On 02/04/2025 at 11:17 AM, Dose Pipe Sutututu said:

Let me hear it, Samsonas 

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I might have to say it.

[Predator1]

  On 02/04/2025 at 11:17 AM, Dose Pipe Sutututu said:

Let me hear it, Samsonas 

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Better then PooPooG... or is it PeePeeG? 

Edited April 3 by Predator1

[MBS206]

  On 03/04/2025 at 5:00 AM, GTSBoy said:

I might have to say it.

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Sell it and buy something newer? 😛

[DRoc81]

  On 03/04/2025 at 4:55 AM, dbm7 said:

Ahh... it's an early RE5R01A box, that means the pinouts I gave are wrong (they were for the RE4R01A 4-speed box)... I'll have to dig around in my docs to see if I've got that schematic (they used the same gearbox plug, with the vacant pin wired to the direct drive clutch solenoid)...prolly hidden away in a supplement somewhere...

...there were 3 variants of the RE5R01A ~ this early schema was what we called the 'dumb' 5 speed ; it's what jatco called a 'medium duty' box, with torque holding up roughly ~200ft/lbs or so, which was good for NA from RB20/25DE and up to around VG30 output spec. With the RB25DET (and VG33/35 mills), the only options they had was the 4-speed 4AX00 box, which had been beefed up to handle the extra torque (primarily for the VG35, but it also suited the RB25DET mill and others)...and the RE4R03 box in large 4WDs a lot of the time...

...the next variant of 5-speed was redesigned, stronger, and 'smart'...first ones had external TCU with internal (on valvebody) Shift Control Unit, pressure switches, and 2 x TSS...and the last ones had internal TCU+SCU setup, with CANbus control etc etc.

@DRoc81 On the RHS of the box towards the rear, there should be a stamped silver ID tag -- what's the model number?

Oh...and with the early 5-speeds, the torque converter control solenoid assembly should be replaced as well (31940-60X00)...it's a bit Murphy's Law ....if one has failed, bet on the rest not being far behind ...

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Interesting.  Great info. thank you.  Give a few days to get that name plate.  I have a busy life most weeks.  I will be in touch.

[DRoc81]

  On 03/04/2025 at 6:22 AM, MBS206 said:

Sell it and buy something newer? 😛

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I mean, I am always taking donations for a newer model!!  If you'd like to sponsor me. I would gladly get something else!! LOL

[DRoc81]

  On 03/04/2025 at 4:55 AM, dbm7 said:

Ahh... it's an early RE5R01A box, that means the pinouts I gave are wrong (they were for the RE4R01A 4-speed box)... I'll have to dig around in my docs to see if I've got that schematic (they used the same gearbox plug, with the vacant pin wired to the direct drive clutch solenoid)...prolly hidden away in a supplement somewhere...

...there were 3 variants of the RE5R01A ~ this early schema was what we called the 'dumb' 5 speed ; it's what jatco called a 'medium duty' box, with torque holding up roughly ~200ft/lbs or so, which was good for NA from RB20/25DE and up to around VG30 output spec. With the RB25DET (and VG33/35 mills), the only options they had was the 4-speed 4AX00 box, which had been beefed up to handle the extra torque (primarily for the VG35, but it also suited the RB25DET mill and others)...and the RE4R03 box in large 4WDs a lot of the time...

...the next variant of 5-speed was redesigned, stronger, and 'smart'...first ones had external TCU with internal (on valvebody) Shift Control Unit, pressure switches, and 2 x TSS...and the last ones had internal TCU+SCU setup, with CANbus control etc etc.

@DRoc81 On the RHS of the box towards the rear, there should be a stamped silver ID tag -- what's the model number?

Oh...and with the early 5-speeds, the torque converter control solenoid assembly should be replaced as well (31940-60X00)...it's a bit Murphy's Law ....if one has failed, bet on the rest not being far behind ...

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  On 03/04/2025 at 11:42 AM, DRoc81 said:

Interesting.  Great info. thank you.  Give a few days to get that name plate.  I have a busy life most weeks.  I will be in touch.

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My plan is to replace both Shift Solenoids A and B, and good idea on the Torque Convertor Solenoid as well.  

[dbm7]

Those 2 solenoids in that assembly I mention, are the PWM solenoids for torque converter lock-up clutch & EPC (line pressure control) ~ when most folks hear of 'solenoid failure', the tendency is to think electrical failure...but fact of the matter is, especially wrt the EPC solenoid (which is moving/running all the time), you can have an electrically 'good' solenoid, that's absolutely broken/worn out mechanically inside...ie; valve plunger return spring rubbing against spring retainer plate, lowering preload pressure..

...and the solenoid armature extension limit spring wafer with bad wear/broken off petals...

...and if there's ever been any metal flying about, damage to the valve plunger end itself...

...the stuff one never really sees, unless you go the whole 10yards trying to answer the question "why is my line pressure screwy, but TCU isn't flagging any EPC solenoid fault?"...and carefully dissect the solenoid. Worst (and most probable) scenario is when the plate spring petals break off, they get held by the magnetic flux, get mashed up by the armature into little bits, which end up in the space between the armature & shading core bore, and things get stuck or randomly jam up, and your line pressure goes flat and doesn't change...and the TCU never sees it, as it doesn't actively monitor LP...

..then it gets into insidious land, if you end up with lower than expected line pressure...lets say high clutch..and the lower pressure causes it to slip ~ when I say 'slip', think say 2000rpm on the drive plates, and 1800rpm on the driven plates, because the slip is making them under-rotate by 200rpm ; you get all the usual nasties like heat and band/clutch wear, but even if it's only 20rpm slip the same thing happens...and... you'll hardly ever pick this up driving the thing with the torque converter active as it effectively masks these sorts of slippages that are line pressure related ...(the newer TCUs can detect clutch slip rate)...just  FYI as it were...

 

[DRoc81]

Thanks for all the information on this.  I tried ordering the parts from Amayama website and all 3 Solenoids are discontinued and not available.  Does anyone have any other websites to suggest that I could find the parts?

 

Separate issue-- I will start a new thread, but basically the vehicle is stalling when warmed up.

[dbm7]

That'd be right ~ the early RE5R01A is pretty much the same as the RE4R01A in many ways ; problem is they made lots more 4-speeds than 5-speeds.... I'm in AU, so you'll need apply the US supply scene...

https://www.alltranz.com.au/shop/drivetrain/automatic-transmission/Mazda/RE5R01A/#scroll-electrical_components

This'll give you the aftermarket parts listings -- you're looking for #56712 & #56713

[joshuaho96]

  On 07/04/2025 at 5:16 PM, DRoc81 said:

Thanks for all the information on this.  I tried ordering the parts from Amayama website and all 3 Solenoids are discontinued and not available.  Does anyone have any other websites to suggest that I could find the parts?

 

Separate issue-- I will start a new thread, but basically the vehicle is stalling when warmed up.

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I saw some online elsewhere: https://www.transmissionpartsusa.com/product_p/67393c.htm?gQT=2

No idea if it's real, how trustworthy they are, etc.

[dbm7]

I'll just reiterate that it's best to do all the wiring diagnostics, before even thinking about buying replacement solenoids ~ that is, be absolutely sure the solenoid is bad.....ie; bad connector(s), rodents chewed through a wire, etc etc. If you don't so this, you can fork out all the money for solenoids, only to find something else is wrong (this'll make you cry if you pull the valvebody only to find a broken wire is at fault...

...some more glue on the solenoid packs -- this is the RE5R01A shift solenoid assembly....

...these are all shift solenoids ~ ostensibly they're the same as the shift solenoids from the 4-speed auto....

...this is the RE4R01A solenoid set...

...with these, you have 3 shift solenoids attached to the plate, and the separate solenoid is the EPC solenoid (line pressure control) -- with both designs, the TC lockup clutch solenoid (also PWM so they could slide the clutch shut), is located on the lower valvebody half....

...(story time)...back in the 90's, it was a common fault that the EPC solenoid (or TC-lock solenoid) would fail, but Nissan only sold them as part of the assembly (think ~$350 at the time) ~ thing was, Isuzu also used these boxes in light commercials, and you could buy the PWM solenoid as a separate part, so it was possible to buy/use that solenoid (around $65), and make it fit (remove the circlip, fit to old plate and deal with wiring)...making it a more cost effective repair.

I've not seen the RE5R01A shift solenoid assembly, but with the 4-speed RE4R01A it was possible to hack/fit a single shift solenoid onto an other working set, using a donor solenoid from another set with failed EPC....(by rights the whole set should be replaced), but it ends up being a question of how much life is left in the box itself ; sometimes it's a viable repair to fix one solenoid, just to get another 100k of road miles out of it before it needs first overhaul...other times the box is that old/worn, you're as well doing first overhaul and replacing the solenoids and starting fresh...

What Nissan did here with the 5-speed, was relocate the EPC solenoid to the lower valvebody (next to the TC lockup solenoid), and stuck the direct-drive clutch solenoid (for the extra gear) where the EPC solenoid used to be on the 4-speed....I can only imagine they did this for serviceability ; the PWM solenoids are most likely to fail, and it's a doddle to drop the pan and change these out (as opposed to dropping the valvebody itself to get at a top mounted EPC)...

...also keep in mind, that some BMW 3/5 series & Mazda (and maybe some Ford/Mazda rebadges, not sure), also used the RE5R01A box under a different name/part number...not saying parts availability is any better, but sometimes it helps to know this when it comes to NOS floating about in the EU....

HTH

 

[soviet_merlin]

Purely out of curiosity, how do you know all this @dbm7? Do you work with automatic gearboxes professionally?

This goes way way way beyond "I've had an automatic Skyline once and did some mucking around"

[MBS206]

  On 09/04/2025 at 4:03 AM, soviet_merlin said:

Purely out of curiosity, how do you know all this @dbm7? Do you work with automatic gearboxes professionally?

This goes way way way beyond "I've had an automatic Skyline once and did some mucking around"

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Thanks for asking the question we were all thinking!

[dbm7]

  On 09/04/2025 at 4:03 AM, soviet_merlin said:

Purely out of curiosity, how do you know all this @dbm7? Do you work with automatic gearboxes professionally?

This goes way way way beyond "I've had an automatic Skyline once and did some mucking around"

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'Did' work on them is more accurate ~ on the R31 Skyline forum, you can spot me as 'Solder'... I've written quite a bit about the 4R01 boxes there, and I ended up reverse-engineering the older TCU type operations, so we could fudge a custom TCU to pull off other tricks...and like all things, when you do it a lot, see the failure patterns, have to find parts etc etc, your head ends up filled with whys and wherefores... there was a reason Nissan went with these in more than 60models over 16+ years... all in all, the JR401E based design is an interesting study, as Nissan changed things over the years in a never ending battle against them lunching on themselves <grin>...by the time the RE4R01A rev.C came out (often referred to as RE4R01B), they'd more or less perfected the design...