Need to find what 5sp tranny has lowest 1st gear

[lonwlf]

I am trying to find out what tranny I can get for my 78 620 4x4 conversion, that will bolt to my L20. Hoping that it is the short 4x4 84-85 ,but can't find much info on what gear ratio's the different years have? Looking for the lowest first gear.

[datzenmike]

Need more info. You should be able to fit the common 31.5" 5spd. in. Why are you looking for a shorty? Is this a home made 4X4 or a 'conversion' with jeep/dana parts?

 

 

Also fill out your profile location, someone may live near you and have what you need. Pictures of your Datsun are also nice. Also:

 

http://forum.ratsun.net/showthread.php?t=703

Edited November 28, 2009 by datzenmike

[lonwlf]

This was a 4x4 conversion. I bought it from the original owner that had the dealer send it out to be done before he picked it up new. So it has the Jeep/ dana 20t-case. I have since removed the front and rear suspension & axles. Now changing it to suite my needs. Narrowed chevy 44 front with 5.89 gears and a lock-rite, shackle reversal with new hangers, Toy rear spring in front and a long travel front drivelive. For the rear I put a 88 Grand Waggy 44 with 5.89's and a spool, and Waggy front 7-leaf sping packs for now. The reason I want a different tranny is to get the gearing lower in low-range. The shorter tranny will make more room for the "Jack-shaft". They only have a single u-joint in it for some odd reason? Have owned several of these and never came across this wierd setup.

[datzenmike]

31.5" long FS5W71B 5spds with 3.592 1st gear ratio were used in the '79 620 and the '80 720 with 4wd. Both will have the correct L series bolt pattern.

 

All 720 4wd have this same low 1st gear but slightly different 2nd and 3rd ratios.

 

All 720s after '80 use a Z series engine bolt pattern.

 

Some come in the short 26.3" length but I'm not sure which models got it. I did get one from an '83 4X4 KC that was short so maybe only long wheelbase trucks?:

 

http://i138.photobucket.com/albums/q251/datzenmike/Tranny/83FS5W71Bshorttail001Large.jpg[/img]"]

 

I have a picture of one with a speedo cable so must be from a 2wd and also an L series bell so it's either from an '80 720 (the only year with the L series motor) or, someone swapped the front case. I've heard a rumor that there was a short competition non overdrive 5spd that would drop into the 510 car. If this is the case it would explain the speedo on the left side.... either way the 1st gear ratio is way to high for what you want being at least 2.818 or lower. Here's the pic:

 

http://i138.photobucket.com/albums/q251/datzenmike/Tranny/trannyFS5W71Bshort0ne.jpg[/img]"]

[RGB]

I can't find it now, but I saw a chart somewhere that listed the diesel transmission in a 720 as having the lowest first gear ratio. The difference was not much though.

[lonwlf]

A chart would be great. I saw a post on another site where a guy was doing dual cases on a TBI v6 4x4 truck and had the first gear listed as 4.0. It would be nice to know. I may still be able to get a motor, tranny ,and T-case out of a 92 4x4 4banger.

[greybeard]

I've been looking into a BW T5 on a turbo 280ZX bellhousing.

The T5 trans is from an S-10 and 1st is lower than any datsun trans I could find. 1st in the truck the T5 is about 4-1

 

The trans bolots to the housing, the center locating diameter needs to be opened, this can be done by any machine shop.

there are some input shaft issues to work out still.

 

another option I was considering is a Muncie SM425, a small 4 speed

from GM trucks from the 60's (I don't remember exactly the years)

This trans is small but HEAVY, and 1st is a compound low granny gear,if I remember it somthing like 7-1, lower than the larger and REALLY HEAVY

SM465 so that makes it a 3 speed for street driving..

 

I was loking at this with the turbo ZX bell and making an adapter

 

 

 

here is a chart I found, no sm425 or 465 on it

 

http://users.erols.com/srweiss/transc.htm

[datzenmike]

Wow, what about going from your 4.375 to an 4.875 rear from a 521 J13?

 

Find a '79 620 5spd, any 720 4x4 or diesel 2wd 5spd, or '84-'86 200sx 5spd. All have 3.592 first gear. The 720 and the 200sx will need the front case swapped to the L series bolt pattern but this has got to be easier and lighter than the other idea.

[lonwlf]

Does the KA 4x4 truck have a lower first? Is there any way to put it on my L -series motor? I would have to come up with a custom adapter for a passenger side front output case but it would be worth it to have it all married.

[datzenmike]

If it does it does not have the divorced transfer case. The D-21/Pathfinder has a transmission and transfer case in one:

 

http://i138.photobucket.com/albums/q251/datzenmike/Tranny/PathVG5spdandTcase001Large.jpg[/img]"]

Edited December 1, 2009 by datzenmike

[lonwlf]

I know that. I can have a friend build me an adapter to change cases. My plan was to put a KA in the truck next summer Then a friend gave me a VG 3.3 so now I'm trying to figure out which one to do. Want to keep the truck light but still have more power than a L20b. I'm going to remount the T-case and run it until then, but a lower geared tranny would be nice for the time being.

[lonwlf]

So my new question is, will the KA tranny bolt to my L motor but just be tilted?

[Guest DatsuNoob]

So my new question is, will the KA tranny bolt to my L motor but just be tilted?

 

It should work. I'm pretty sure the motor will lean to the pass side instead of the driver's.

[datzenmike]

Mr. Noob is correct. The tranny will be tilted 12 degrees over to the passenger side. You will need a wedge in the mount to properly support it, the shifter needs a bend in it to make it sit more vertical and the shift hole in the floor may need to be opened up a bit.

 

Also the FS5W71C from the KA will be longer by 1-2" if from a D-21 to 4-5" if from a 240sx. The drive shaft will need shortening.