Donor 5-speed question

[raggmann]

Ok, I searched but didn't really find what I wanted.........

I have a '72 PL521 that's pretty much stock as far as the running gear.

I found an '83 720 with a 5-speed that I can get the tranny out of for pretty much nothing (along with the gas tank).

Will it work with my L16?

What do I need to look for if there are different versions of the 5-speed?

I figure I'll need to shorten the drive shaft(s) in the 521 but that's no big deal.

What else needs to be done?

I'm pretty sure I'll have to modify the mount but I'm a little mixed up at this point.

This "donor" is about 1-1/2hr drive away and I don't wanna bother if it'll end up just being more scrap around the yard to add to my D21 parts that I don't even have a truck for.

[datzenmike]

It can be made to fit and work but as it is now... no.

 

First the length, the 521 is around 26". Measure the 720 5 speed. (some are short some are long) it would be good to know.

 

The 521 uses a bolt on spline with a flange that bolts to the rest of the driveshaft. You can use this spline but it will have a hole in the end where the nut used to be and it will leak oil. You can plug with a 40mm frost plug or maybe you can get the end of the 720 driveshaft?

 

Bolt on spline with flange...

 

Flange removed, bolt on end of mainshaft...

 

 

Hole where bolt was plugged.

 

 

If possible get the speedo cable from a '74 and up 620 for extra length.

 

Keep and use the release bearing collar that is on the 521 and put on the 720 tranny's clutch arm.

 

Hole in floor will need to be opened up further back and the cover pan moved back and bolted down.

.

[raggmann]

Mike to the rescue once again.

What 5-speed donor am I looking for?

What if I got the drive shaft, etc off the 720, would that help or???

I'm thinking that for $50 I may as well try it.

Thanks

[datzenmike]

Your 521 has a two piece driveshaft. The very back of the first half is supported by a carrier bearing to keep it from 'flopping around' in the middle. The front half can be removed and shortened slightly to fit a longer transmission in there. The 720 driveshaft is likely two piece as well, but unlikely to be the correct length, but the spline fits the 5 speed. Better to keep the 521 and shorten it because the 720 carrier bearing may not fit the 521 perfectly.

[wayno]

Ok, I searched but didn't really find what I wanted.........

I have a '72 PL521 that's pretty much stock as far as the running gear.

I found an '83 720 with a 5-speed that I can get the tranny out of for pretty much nothing (along with the gas tank).

Will it work with my L16?

What do I need to look for if there are different versions of the 5-speed?

I figure I'll need to shorten the drive shaft(s) in the 521 but that's no big deal.

What else needs to be done?

I'm pretty sure I'll have to modify the mount but I'm a little mixed up at this point.

This "donor" is about 1-1/2hr drive away and I don't wanna bother if it'll end up just being more scrap around the yard to add to my D21 parts that I don't even have a truck for.

Hi there Raggmann, I have never seen a shortshaft 5 spd. in a 1983 datsun/nissan 720 PU, that doesn't mean they didn't put it in it, I just haven't seen one, so that would likely mean that Datzenmike has explained most of what you need to do to install a longshaft 5 spd.(31 inches) except that the donor truck more than likely has a napZ engine, and will have the napZ transmission bolt pattern, this means you will also need a 1980 datsun longshaft 4 or 5 spd. front caseing from a L20b block 720, as this will have the right transmission bolt pattern, otherwise your tanny will be tilted badly. There is a lot involved to make a shortshaft truck 5 speed that will bolt into a 521 without a lot of modifacations. As for the fuel tank out of the 720, you would have to fabricate mounts if it is a kingcab fuel tank, and it would likely need to be installed on the pass. side, unless you do some creative plumbing as the filler is pointed towards the pass. side. The regular cab 720 tank is to big to fit between the cab and axle on the 521 PU under the box as far as I know. wayno

[Sealik]

Hi there Raggmann, I have never seen a shortshaft 5 spd. in a 1983 datsun/nissan 720 PU, that doesn't mean they didn't put it in it, I just haven't seen one, so that would likely mean that Datzenmike has explained most of what you need to do to install a longshaft 5 spd.(31 inches) except that the donor truck more than likely has a napZ engine, and will have the napZ transmission bolt pattern, this means you will also need a 1980 datsun longshaft 4 or 5 spd. front caseing from a L20b block 720, as this will have the right transmission bolt pattern, otherwise your tanny will be tilted badly. There is a lot involved to make a shortshaft truck 5 speed that will bolt into a 521 without a lot of modifacations. As for the fuel tank out of the 720, you would have to fabricate mounts if it is a kingcab fuel tank, and it would likely need to be installed on the pass. side, unless you do some creative plumbing as the filler is pointed towards the pass. side. The regular cab 720 tank is to big to fit between the cab and axle on the 521 PU under the box as far as I know. wayno

 

 

Ya...I don't think there were any 2WD 720s with a short tail.....?

4x4s started using them in 83

One quick way to determine trannie length without getting under the truck...is....the console.

 

 

 

[wayno]

Hey Sealik, 85 and 86 nissan regular cab shortbox 720 pickups had 5 speed shortshafts in them with the console on the left in your photo above, 4 wheel drive trannys are almost useless without a speedo drive, but I have seen a few 2wd shortshaft trannys in 4X4s, I suspect that was all they could find at the time to replace there bad tranny. You right also, it's a lot easier and faster to just glace in the cab to determine the tranny size, than crawling under the truck. :D

[Sealik]

Hey Sealik, 85 and 86 nissan regular cab shortbox 720 pickups had 5 speed shortshafts in them with the console on the left in your photo above, 4 wheel drive trannys are almost useless without a speedo drive, but I have seen a few 2wd shortshaft trannys in 4X4s, I suspect that was all they could find at the time to replace there bad tranny. You right also, it's a lot easier and faster to just glace in the cab to determine the tranny size, than crawling under the truck. :D

 

 

Ya...I can see that...don't have any 2WD to compare, although....did have a 85KC ST...had a long tail.

Cab space....shorter trannie for the smaller cab I guess.

Just swapped a 31 long tail for my 26", in my 84 4x4 reg cab.

Had to pull the bench seat to install the longer console... :blink: .... :D

[datzenmike]

Would love the tailstock from a 2wd shorty. Only takes a few min to remove it. Actually the whole tranny as it has better ratios for a car that the 4x4 one.

 

Here's one with an L front case on it. Perfect for the 510, even has the speedo on the correct side.

 

[HowlerMonkey]

Does anybody know if the guts from a fs5w71g transmission from the 1986.5 to 1995 trucks can be fit to the fs5w71b transmission case.....or any other mixture between the two?