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Help! 1981 Datsun 720 King Cab Transmission

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I became the new owner of a 81 king cab 4x4 that has a 0 mile rebuilt z22 engine but no transmission. Are there any 5 speed transmissions that are direct bolt ons and if so what vehicles are they from? I have access to a 4 speed 720 transmission, would that fit and if so would I even want to put in a 4 speed when it should have a 5 speed?

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Welcome :)
 

Is the transfer case there?

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1/ the 720 had three different series of engines.The L20B the Z20/Z22/Z24 and the SD22/25 diesel.

L20B........................... '80

Z22............................. '81-'82

Z20 and Z24.............. '83-'86.5

SD 22 and SD25........ '81-'86.5

 

2/ As they are*, the L20B and the SD (diesel) transmissions won't bolt to your Z22 but the Z20 and Z24 ones will.

 

3/ You are lucky as a 2wd transmission will work in a 4x4 but not so well the other way round. This is because there is no speedometer drive in a 4x4 transmission, it's in the transfer case.

 

4/There were two 5 speeds, identical, but for their length. If buying one, it would be best that it match yours for length. They were 26." and a 31.5" long. So find out.

 

 5/ Four and 5 speeds. (this applies to 4x4s as well) Five speeds were an option on L20B and Z22 engines but there were no 4 speeds on the Z20, Z24 and the SD diesels, in fact there were no 4 speeds after the '82 model year. There's nothing wrong with a 4 speed and it will bolt to your Z22 if.... 3/ is the same length. If you do a lot of highway driving a 5 speed would be nice, but not required. It's really meant to lower highway RPMs and save a little gas. It does NOT make you go faster.

 

6/ Other Z series transmissions are the '80-'83 S110 200sx car. These are all 31.5" long.

 

7/* What makes a transmission fit your Z22 is the front case with the engine bolt pattern. So if you have a 4 or 5 speed front case you can swap it onto an entire host of other 71B transmissions and 'convert' it to a Z series. Say you find an old destroyed 4 speed for nothing. You remove the front case and save it. Later you find an '85 S12 CA20E transmission. You put the Z series front case on and now it fits your Z22. Doner vehicles with the 71B transmission are...

 

31.5" long

'78-'80 810

'81-'84 Maxima

'80-'83 S110 200sx

'84-'86.5 S12 200sx

'77-'78 280z

'79-'83 280zx

'77-79 620 truck

 

Could be 31.5" or 26"

'80 720 truck L20B engine

'81-82 720 truck Z22 engine

'83-'86.5 720 truck with Z20 or Z24 engine.

'81-'86.5 720 truck SD22 or 25 diesel

 

 

 

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3 hours ago, datzenmike said:

1/ the 720 had three different series of engines.The L20B the Z20/Z22/Z24 and the SD22/25 diesel.

L20B........................... '80

Z22............................. '81-'82

Z20 and Z24.............. '83-'86.5

SD 22 and SD25........ '81-'86.5

 

2/ As they are*, the L20B and the SD (diesel) transmissions won't bolt to your Z22 but the Z20 and Z24 ones will.

 

3/ You are lucky as a 2wd transmission will work in a 4x4 but not so well the other way round. This is because there is no speedometer drive in a 4x4 transmission, it's in the transfer case.

 

4/There were two 5 speeds, identical, but for their length. If buying one, it would be best that it match yours for length. They were 26." and a 31.5" long. So find out.

 

 5/ Four and 5 speeds. (this applies to 4x4s as well) Five speeds were an option on L20B and Z22 engines but there were no 4 speeds on the Z20, Z24 and the SD diesels, in fact there were no 4 speeds after the '82 model year. There's nothing wrong with a 4 speed and it will bolt to your Z22 if.... 3/ is the same length. If you do a lot of highway driving a 5 speed would be nice, but not required. It's really meant to lower highway RPMs and save a little gas. It does NOT make you go faster.

 

6/ Other Z series transmissions are the '80-'83 S110 200sx car. These are all 31.5" long.

 

7/* What makes a transmission fit your Z22 is the front case with the engine bolt pattern. So if you have a 4 or 5 speed front case you can swap it onto an entire host of other 71B transmissions and 'convert' it to a Z series. Say you find an old destroyed 4 speed for nothing. You remove the front case and save it. Later you find an '85 S12 CA20E transmission. You put the Z series front case on and now it fits your Z22. Doner vehicles with the 71B transmission are...

 

31.5" long

'78-'80 810

'81-'84 Maxima

'80-'83 S110 200sx

'84-'86.5 S12 200sx

'77-'78 280z

'79-'83 280zx

'77-79 620 truck

 

Could be 31.5" or 26"

'80 720 truck L20B engine

'81-82 720 truck Z22 engine

'83-'86.5 720 truck with Z20 or Z24 engine.

'81-'86.5 720 truck SD22 or 25 diesel

 

 

 

 

Great information. Thank you. I purchased a 4 speed transmission from a 81 4wd 720 off of Ebay before I realized that a 5 speed is what is supposed to be in the truck. Since the donor truck is the same year and also a 4wd it should just bolt right in correct? I have the engine, divorced transfer case, and both drive shafts but none of them are installed on the truck. Without them in place is there any way to find out what length transmission (26 or 31.5) that I am supposed to have? 

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The truck might have had a 5 speed but it doesn't have to have one. It was an option.

 

The 4 speed will work if the lengths are correct. I think only the 5 speeds could come in the 26" length so it will be 31.5" long.

 

JZxpsJG.jpg

 

This short driveshaft to the transfer case would work with the longer 31.5" transmission.

 

 

 

Xu5DybA.jpg

 

This longer driveshaft to the transfer case works with the shorter 26" transmission.

 

 

Sorry I can't say what 720 got the short or long transmissions or why.

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Have a look at the VIN or maybe the driver's door plate or the engine plate on the inner fender under the passenger side hood hinge. Look for his grouping of letters...  KMLY 720 FU

 

This would be a king cab Z22 engine left hand drive 4x4 720 DX (long wheelbase) and the F would denote a five speed installed when built, (a T is for 4 speed)... U is federal emissions.

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I just went out and checked and I have the shorter drive shaft. I also ran out and checked the truck but its raining and wasnt able to be too thorough. The only plate I could find was the one with my vin number JN6MD06Y8BW

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Before '82 manufacturers made up their own VIN and there was no standardization. From around '82 on there was the 17 digit VIN.

 

J..... made in Japan

N.... Nissan?

6........truck

M......... Z22

D......... truck

0......... model change.

6........... king cab

Y............ 4x4

8........... check digit

B........... 1981

W........... Kyushu plant

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Do you know if all the 4 speed transmission were standard lengths and if so were they 31.5 inches or 26? I know the truck is a 81 4x4 DX and thats about all I know. I now own 9 vehicles but I'm mainly a vw guy. This is my first datsun so apologies for any amateur questions. To be honest until last week I didnt even know what a datsun 720 was. A kid from oriellys saw that I had some motorcycles and the truck is what he had to trade. So I traded 3 not running motorcycles and a not working winch for the truck. I paid $280 for the motorcycles and he was trying to sell the truck for $800 so I traded. 

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I've never heard of a shorty 4 speed. Not that there aren't any just I don't think there are.

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So i need a 31.5 inch transmission and the 4 speed ebay transmission I bought that didnt list a length is more than likely 31.5 inches and should bolt right in? The only difference Inbetween my truck and the ebay parts truck that I see is that mine is a king cab and the ebay one is a standard. Thanks again for all the information.

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