1980 720 4x4 specs needed

[frank1669]

hello everyone:  I am brand new to this forum and this is my first post.   I Just bought a 1980 Datsun 720 4x4 from a local car dealership in non running condition.  the body is shot but that’s ok I wanted the engine tranny and t-case. to use in a Suzuki build ( please Don’t hate me) 

I ordered a  factory service manual but I haven't received it yet. I am ignorant the tranny and transfer case model numbers

The fender tag is completely  blank apparently it was just painted not stamped  like what I have seen on here. So my questions are? 

Its a 4 speed which one is it? and what are the gear ratios for 1st 2nd etc. ?  is the 5 speed stronger or have a deeper first gear? 

who makes the t case and what gear ratio are the in high and low range?  It is a divorced  t-case.

The under hood emissions label says it’s a T20B engine family is this the same as an L20b?

I am sure I will have lots more questions later but this should get me started. thanks

[datzenmike]

The tag should be embossed those first few years but....

 

 

Engine............... L20B There is no T20B, it must be some emissions thing.

Transmission...... F4W71B 4 speed optional FS5W71B 5 speed

1st....... 3.592

2nd...... 2.246

3rd...... 1.415

4th....... 1.000

 

The 5 speeds for this year are the same strength and gear ratios with a 0.882 overdrive 5th 

Earlier L series transmissions in other vehicles came with a 3.321 and a 3.062 first gear.

 

T-100 transfer case with 2.074 low ratio. Who makes them? Probably who makes all the Nissan transmissions. I often see an Hitachi emblem  on trans part castings. Perhaps Fuji Heavy Industries. Nissan used to be a co-owner.

[MikeRL411]

The "painted" fender tag is a prime example of what happens when unscrupulous owners/resellers  order  "reproduction"tags in order to legitimise their counterfeits.  It's fraud no matter what the buyers say.  You can doctor a tag to say that your 1968 510 came with a V6 if you want to.

[frank1669]

Thanks for the fast replies,  I kind of doubt it being a repo tag as I doubt the truck was ever worth enough to go through the bother, but who knows.  Thanks for the model numbers now I think my searching will provide far better results. 

[frank1669]

I just read a post on "mystery 5 speed" and  it was a "L" series case on a later FS5W71B transmission. 26" instead of 31.5"   

For my application this would be the perfect tranny. the shorter I can keep everything the better as I am dealing with an 80" wheelbase.  is there a How to write up anywhere on building this tranny?  would I be able to use any of the parts from my F4W71B 4speed ?  Maybe a list of suitable donor vehicles?  and would it still have the 3.592 first gear ratio.   See I told you I would have a bunch more questions.  Thanks

[datzenmike]

The 26" is found on later 720 trucks. (get a 2wd as it has the speedo cable in it unless yours is from the trans case) ... then any 4x4 'shorty' will work.

 

Your 4 speed front case will fit it with minor mods. I have to go to work but can list them tonight (if I remember) and maybe post some links to swapping the front case so you know what problems you might face.

[frank1669]

that would be awesome, I appreciate it. thank you.

[datzenmike]

The '74 and up 620 and all the 720 trucks used either a F4W71B  four speed or an FS5W71B 5 speed. They came with different front cases to reflect the bolt pattern used between the L and the Z series motors they were bolted to. But other wise were pretty much the same transmission. Later 720 trucks only came with 5 speeds and also in two different lengths. The most common was the 31.5" but there were later shorty 26" lengths. I've never figured out which models or years got which but you can tell by looking at the console length. Doug, (Sealik http://community.ratsun.net/user/2344-sealik/ can probably provide a picture of what to look for in a 720 to quickly tell if it has a short transmission.

 

Here is some info on removing the front case from any 71B transmission... http://community.ratsun.net/topic/8809-how-to-remove-tranny-front-case/

 

Now that you can remove the front case there may (or may not) be some slight differences. One is that later 5 speeds (after '84)  got rid of the 56mm counter bearing and upgraded to a 62mm one. Naturally this larger bearing will not fit the 56mm hole in your four speed front case. So two ways to go. Have the case milled to take the larger bearing or just remove it and hammer on the 56mm one. Two the 1st/2nd shift rod diameter may have been increased from 14mm to 16mm. If so the 16mm rod end won't fit your 14mm hole. So get your Black and Decker electric drill and make the hole larger.

 

Your 4 speed front case will look something like this inside. Note the distance between it and the bearing hole above it. Note also the three shift rod holes on the right are the same size.

 

This is a later 71C for example only. Note the holes appear closer because the bottom one is for the larger 62mm bearing. Note also that the top 1st/2nd shift rod hole is also larger.

 

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