Hi guys

Has been hard to find info on this topic, so appreciate any input and/or useful links.

Looking at retaining the factory CA18DET auto box, with upgraded clutch pack / modified automatic valve body / small converter.

Firstly I'm wanting to know if anyone can definitely advise if the box will be the Jatco RE4R01A or the Jatco L4N71B as I have been told that it could be either.
Secondly I'm wanting to know if the factory trans control will cope OK with this and/or how best to modify shifting behaviour - again noting that it is staying full-auto.

Thanks for your input*

* a free kick in the nuts to the first person that tells me to go for a 3sp or to change it to manual shift.

I'll take that kick in the nuts.

Shifty, not sure I can help with the answer, but perhaps can help others to answer...

Just so I can get my head around this:
1. Are you asking how to tell the difference between the two boxes, or
2. Which box would usually be on the back of a CA18?

Do you have the box already?
Sounds like the RE4R01A is usually mated to RB motors as it's considered a 'medium duty' box.
What car is the CA18 you have out of?
Are you asking because you want to know what kind of parts to buy?
Perhaps speak to an auto reconditioner? Where abouts are you located?

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1972 Datsun 1600, S14 SR20DET Engineered (204rwkW @ 17psi.)
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#SR20Datsun @SR20Datsun

Two things I want to know:

1. What auto box is behind the CA18DET (or were both available at different times).
2. Is there any knowledge on modifying shift behaviour by modifying/changing/piggybacking the auto computer.

Done heaps of searching but no clear answer. Some sources (eg. Wiki) suggest that it is definitely an RE4R01A but others suggest it is the L4N71B. Obviously autos aren't the standard choice for these engines so knowledge seems to be very patchy & the people who retain autos tend to go to the Jatco 3sp using the Bluebird/910 bellhousing & convert to manual shift.

Obviously it is very hard to do any further research on upgrades if I don't know what box I'm working with. As the box is in the car, it is near impossible to identify (for me, anyway).

I have consulted a well-respected auto shop and they were unsure which of the two boxes it would be - they don't pull them out of cars, they just get them on the bench and work their magic.

So far I have been able to confirm that if it was an S13 CA18DET, then it will have the RE4R01A box. Also after further Googling I was able to establish that the RE4R01A has a rectangular sump /sump gasket, whereas the L4N71B has a rectangular sump / sump gasket with an extra rectangular section on one edge.

Based on all of this I have been able to establish that my box is the RE4R01A & therefore that my engine must be ex-S13.

So that solves the first part

Now just need to know if there's anything I can do with the control box to change shift behaviour (or, if the control box will cope with a few mods & the upgraded valve body). Not many people interested by the looks so I might just give it a bash and see how it goes!

RE4R01A gasket:



L4N71B gasket:

Not sure how the computer controls the auto gearbox, and if it does much at all? Have a look into the automatic transmission module in the wiring diagrams and see if you can pull.anything from it. I believe there is a wire in it that monitors engine temp.

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910 S3 Bluebird - FJ20ET, E85, IRS, 5 Speed, 4.4 LSD
910 S3 TRX - RB25DET, Coilovers, S13 Front end, Power Steering
RA23 Celica - 18RG, Twin 40mm Webers, Coilovers, rolling on SSR mesh 15x7 0s.

Best I have been able to figure, it changes gears based on (perceived) road speed. If you could tap into that signal with some electronic trickery to pull it up/down perhaps it would allow some degree of agricultural adjustment?

If it's the RE4R01A, then have a chat to some of the Skyline guys. They may have run kits through theirs?
Another contact which may be helpfull is Pete from PLMS in S.A.

_________________
1972 Datsun 1600, S14 SR20DET Engineered (204rwkW @ 17psi.)
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#SR20Datsun @SR20Datsun

In all honesty theirs no use talking to the skyline guys as everyone throws the auto in the bin for a manual or a 3 speed for drag. I have never really heard much modifications in the way of these boxes but I also know that they don't reliably hold the power of the turbo motors. What you might want to look into is the vl boys because they can't understand how to use a clutch. Therefore lots of worked autos and I know they're jatco's to just not sure on the model. Also unsure if they have electronic overdrive or not I know the 31's do.

Look up KEAS automatics(can't post a link from my phone)
They are JATCO freaks, mate ran one of his box's in his VL turbo it ran mid 9's.
Never broke either.

Thanks for your input, although it's fair to say that both boxes in question can reliably handle 'the power of turbo motors' with the normal upgrades. Plenty of VL guys have the earlier 4sp Jatco into the 11's (which is about the limit of their reliability) and the later boxes, as per an email from Keas, are fantastic boxes and able to handle ~600hp with minor upgrades.

Agh fair enough mate had one in a rb30e original turbo box but when he wound the boost upto 12 the bands started slipping to the point of undrivability and heard a fair few flaring out auto's at skyline cruises. Sorry if it was misinformation just personal history around them.

I was having a look at an old ZOOM magazine and found an advertisement from BMS
www.bmsproducts.com.au in sydney.
They were suggesting they had shift kits for both the boxes you are referring to.
The valve bodies they are referring to supposedly remove electronic control and go completely manual.
Not sure if this is what you are after, but i'm sure you can have a chat to them about other bits and pieces!

_________________
1972 Datsun 1600, S14 SR20DET Engineered (204rwkW @ 17psi.)
viewtopic.php?t=6579
#SR20Datsun @SR20Datsun

Yes there are some mods to correct this so it can handle 500hp. One, is the shift modulator from a 280sx automatic I believe. The spring needs shimming for the oil pressure modifier valve. This may, who am I kidding? this will very likely make the shifts very harsh for street use.







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