'80 720 5spd into 620

[Farmer Joe]

so it gettin to be that time where i get to puttin the 5 speed in the 620. so now i just need to get all the facts straight.

 

so first off. ive measured the automatic vs the 5 speed. there both 31.5in long, and both trannymounts are at like 27 or something i think?? they both have the same tranny mount position. so i know the driveshaft is the right length.

 

nwo i just need to make sure i could use like a 'z' series 6 bolt flywheel on my l20b.

 

and then i have one more question...

 

how far off will my speedo be with the 720 5 spd and the 76 auto 4.375 gears?

 

thanks!!

[bonvo]

are you putting in the z motor as well or continuing to run the l? if your running the l the transmission will lean to the passenger side

[datzenmike]

The '80 720 will have an L series motor in it. This was the last year the old L20B was used before the 'new' NAPS Z series were introduced in '81.

 

You mention a Z flywheel... so check what motor is in the '80. Either you have the year wrong or the motor has been replaced. As bonvo stated a Z tranny when bolted to an L motor will lean 12 degrees to the passenger side and the shifter will be leaning against the passenger seat.

 

BTW you can use either an L or Z flywheel on your L20B. Must be 6 bolt of course.

 

NEED TO KNOW:

1/ Is this 720 2 or 4 wd? .... a 4X4 won't have a speedo drive in the tranny, it's driven from the transfer case.

 

2/ Does it have an L20B in it? .... If it does have a Z22 in it, the tranny will still bolt up. The shifter could be bent to the left to bring it up-right. The tranny mount may need a wedge shaped shim to allow for the tilt to the right.

 

The speedo cog in the tranny is matched to the rear end in ANY vehicle. If you swap trannys and you don't know the doner vehicle's rear end ratio or tire size, simply take your old speedometer drive pinion and cog from the old tranny and install in the new one. This keeps the matched cog and rear end together, and there is no speedo error introduced.

Edited February 8, 2009 by datzenmike

[Farmer Joe]

well i guess i didnt fully explain what i was doin.

 

anyways, the tranny is from a 1980 2wd 720 that had an L20b.

 

im puttin it behind the l20b in my 76 620, but i dont have a manual flywheel anymore.

 

so im just making sure i can put a 6bolt flywheel from a Z20/22/24 on the L20b. L series motors around here are pretty slim pickins. the Z motors are alot more abundant around here.

 

and then the speedo question.

 

so all i need to do is take the speedo cog from the auto tranny i have now and put it in the 5 speed, and itll keep my speedo correct?

 

thanks for the help everyone!

[datzenmike]

Your current auto speedo into the new tranny.

 

Measure the '80 tranny length just to be safe. Should be 31.5" in order to fit the '76. 720 had two lengths and I don't know what one was on it. All I have ever seen were long tails like the 620 but I know that there were short tails as well.

 

All six bolt flywheels will bolt up to your motor. The flywheel, however, determines what clutch size you can use. There are three different pressure plate bolt patterns for the three different clutch sizes: L20B cars are 200mm, 620 truck L20Bs are 225mm. 720 Z24 use 240mm all 4X4 no matter the engine size use 240mm, not sure what size the Z22s are, 225mm at least. Best to measure across the face to be sure.

 

This is a 240mm from an '80 720 4X4 L20B.

http://i138.photobucket.com/albums/q251/datzenmike/Tranny/flywheel240mmthree2Large.jpg[/img]"]

Edited February 9, 2009 by datzenmike

[Farmer Joe]

alrighty then!

 

yeah the 80 5 speed is 31.5in long.

 

im gonna go grab a flywheel from a z24 720 at the yard thats got the tranny yanked already.

 

thanks for the help!

[datzenmike]

OK, now you need to find the collar or housing that holds the release bearing. Like the speedo cog and rear ratio, the collar is matched to the size of clutch used. Try to find the one that was on that tranny. If you are buying a new clutch see that you get a new one with it.

 

 

Here's some examples. The difference is small but important.

 

http://i138.photobucket.com/albums/q251/datzenmike/Tranny/transreleasebearings2Large.jpg[/img]"]

 

http://i138.photobucket.com/albums/q251/datzenmike/Tranny/transTOBearings.jpg[/img]"]

Edited February 11, 2009 by datzenmike

[Dime Dave]

Here are some links to additional throw out sleeve dimensions and part numbers.

http://datsun510.com/photopost/showphoto.php?photo=6980

 

and

http://datsun510.com/photopost/showphoto.php?photo=6981