oneslick720 Posted May 16, 2014 Report Share Posted May 16, 2014 I have an 86 720 z24, it has a 5 speed but REALLY need to put an auto in it, question is what trans do I need to look for.. I'm not really wanting the stock 3 speed auto, what are my other options? And what will indeed to get with it?.. Tail shaft length, cross member and mount locations does not matter being that it is a full frame build I know this has been touched on before but I never really rear a for sure answer Quote Link to comment
datzenmike Posted May 16, 2014 Report Share Posted May 16, 2014 What's not to like with the stock Z24 3N71B automatic? Has torque converter lock up. The '86.5-'89 D-21 Hardbody with the Z24i motor uses an L4N71B 4 speed automatic. Same 1,2,3 but with a BIG 0.686 4th gear. You may have to shorten your driveshaft slightly as it's an inch or so longer. In both cases you will need the coolant lines and an automatic rad or a transmission cooler for an RV. Get the auto flex plate and the small round adapter plate that fits over the end of the crankshaft. Quote Link to comment
oneslick720 Posted May 16, 2014 Author Report Share Posted May 16, 2014 The stock trans just seams to need one more gear at highway speeds.. What about any computer or wiring? I have a brand new 21 circuit painless wiring going in and ditching all stock wiring Quote Link to comment
datzenmike Posted May 16, 2014 Report Share Posted May 16, 2014 Unless there is something wrong with the stock wiring leave it alone. Painless? is pain in ass and you'll give up and sell the truck. The stock Z24 auto has a torque converter lock up. Check that it's working. Doesn't really matter if it seems like it needs another gear it's just an impression. Seems like doesn't mean it does. Billions were made and they run just fine. It won't blow up.... Quote Link to comment
ggzilla Posted May 16, 2014 Report Share Posted May 16, 2014 By that logic, the 4-speed is great and no one needs a 5-speed. Quote Link to comment
oneslick720 Posted May 16, 2014 Author Report Share Posted May 16, 2014 The original wiring was trashed! This is a show truck, chevy billet steering column and all billet nobs, (wipers, headlights new ignition. ECt ECt ECt ). Everything is new... Full air ride full frame, from the wheel tubs I do not have room for a functional clutch pedal witch is pushing me towards an auto. Quote Link to comment
oneslick720 Posted May 16, 2014 Author Report Share Posted May 16, 2014 I also saw that a 240 trans will fit but the guy had done the 5 speed andcouldntspeak for the auto Quote Link to comment
tr8er Posted May 16, 2014 Report Share Posted May 16, 2014 Also consider a different differential. It may quench your desire for one more gear. Not sure what you have though. A show car doesn't need to drive well. But I understand wanting to enjoy driving it anyway. I think you need a paddle shifter. Skip the mechanical clutch all together. Quote Link to comment
ggzilla Posted May 16, 2014 Report Share Posted May 16, 2014 Oops, show truck done wrong, no room for a clutch pedal. Yes I'd go for a fully automated transmission. Quote Link to comment
oneslick720 Posted May 16, 2014 Author Report Share Posted May 16, 2014 We have thought of air actuators or even a hydraulic hand clutch but wanted to go with an automatic from the beginning And trust me there is no oops and nothing at all gone wrong Quote Link to comment
q-tip Posted May 16, 2014 Report Share Posted May 16, 2014 If you need more gear the 3N71B is definitely not what you want, try to find the L4N71B, it will give you the highway capability you need. Quote Link to comment
izzo Posted May 16, 2014 Report Share Posted May 16, 2014 I've been wanting to do a 720 4x4 auto conversion sometime. Glad to see you on the way to doing this. You shouldn't need any computer wiring junk. Really, there is a modulator that is on the side of the trans that hooks up to a vacuum line via the intake for kick down. Should be a pretty simple swap. Just grab the cooling lines, make sure the kick down is hooked up, and swap radiator from manual to an automatic one. Should be a bolt in affair. you will need the flex plate as mike said and the sandwich plates for it. (make sure and mark which one goes where and what way they point). And the drive line may need swapped off with another one... Take pics, i wanna see. Quote Link to comment
q-tip Posted May 16, 2014 Report Share Posted May 16, 2014 Another thing to keep in mind is how much bigger the L4N71B is than a 3N71B, might have to make some modifications to make it fit Quote Link to comment
oneslick720 Posted May 16, 2014 Author Report Share Posted May 16, 2014 If you need more gear the 3N71B is definitely not what you want, try to find the L4N71B, it will give you the highway capability you need. And what would I find this trans in? That's where I'm at with it as of now Quote Link to comment
oneslick720 Posted May 16, 2014 Author Report Share Posted May 16, 2014 Making it fit isn't an issue at all.. It's just what trans will actually bolt to the block and will work Quote Link to comment
izzo Posted May 16, 2014 Report Share Posted May 16, 2014 have a link to show truck so we can see it? 1 Quote Link to comment
ggzilla Posted May 16, 2014 Report Share Posted May 16, 2014 The 4N71B 4-speed automatic came in * Nissan Maxima 1983 (L-series bell housing) * Nissan Pathfinder 1986-1989 * Nissan Van 1987-1989 (the 'rare as' USA Vanette) * Mazda 929 1988-1990 * Mazda B2000\B2600 1987-1991 ** 1987-1988 has Mitsubishi bell housing? * Mazda Miata 1991-1997 (Mazda N4A-EL) * Mazda RX7 1984-1988 * 1984–1988 Nissan 200SX * 1984–1989 Dodge/Plymouth Conquest * 1984– Mitsubishi Starion * 1986–1989 Nissan pickup * 1989–1995 Mazda MPV Quote Link to comment
datzenmike Posted May 16, 2014 Report Share Posted May 16, 2014 And what would I find this trans in? That's where I'm at with it as of now Already answered.... What's not to like with the stock Z24 3N71B automatic? Has torque converter lock up. The '86.5-'89 D-21 Hardbody with the Z24i motor uses an L4N71B 4 speed automatic. Same 1,2,3 but with a BIG 0.686 4th gear. You may have to shorten your driveshaft slightly as it's an inch or so longer. In both cases you will need the coolant lines and an automatic rad or a transmission cooler for an RV. Get the auto flex plate and the small round adapter plate that fits over the end of the crankshaft. I don't get this... The stock trans just seams to need one more gear at highway speeds.. What about any computer or wiring? I have a brand new 21 circuit painless wiring going in and ditching all stock wiring The 5 speed needs another gear?????????? How will going to an automatic help? Quote Link to comment
bryant2482 Posted May 17, 2014 Report Share Posted May 17, 2014 this would be a good swap. i use to have the 3 speed auto in mine, i didnt like it! it shifted through all 3 speeds by the time i hit 20 mph's and couldnt even burn out on wet pavement! my friend has the L4N71B in his hardbody and im very impressed with the performance, especially at highway speeds in 4th gear! it cruises at 75mph's at about 2700 rpms Quote Link to comment
ggzilla Posted May 17, 2014 Report Share Posted May 17, 2014 The LN371B is a great transmission. It'll cruise at 75mph @ 3500 rpm going up hills even. Very tough and reliable transmission. Keeps the engine in the powerband. The LN4 will return better fuel economy. Quote Link to comment
q-tip Posted May 17, 2014 Report Share Posted May 17, 2014 What you want is a L4N71B, the three speed just doesn't cut it on the highway, or over 50 for that matter Quote Link to comment
oneslick720 Posted May 21, 2014 Author Report Share Posted May 21, 2014 Already answered.... I don't get this... The 5 speed needs another gear?????????? How will going to an automatic help? The 3 speed trans needs another gear which is why I'm trying to figure out what 4 speed I need Thank you for all the help guys ... I'll be on the hunt now Quote Link to comment
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