How to put together a shortshaft 5 speed for a L20b

[jrock4224]

I see what I did there ..... Get a couple trannies and DO it....hahaha

[datzenmike]

When I put a long 5 speed in my short 4 speed 710 I should have measured down from some point on the tunnel to the driveshaft so that when the tranny was lifted into place it could more closely match the original. This would have returned the motor/trans to roughly it's original position in the car. As it was, the longer tail forced the driveshaft to tilt up more anyway. But if a short 5 speed like yours was used this would have eliminated any driveshaft vibration from a changed angle.

 

BTW on most cars (if not all) the rear tranny crossmember is removable so the tranny simply just lifts up into place. I changed a 4 speed in a 521 once and I seem to remember removing one of the torsion bars for some room.

 

Anyway, good write-up and good to know that the theory of a homemade short 71B 5 speed fitting a 521 is a fact now. I always wondered if the 4 speed clutch arm from a F4W63A and a 71B clutch arm were interchangeable. When I did my swap I kept the 71B arm anyway but I did wonder. They are very similar looking.

[mklotz70]

I see what I did there ..... Get a couple trannies and DO it....hahaha

 

Took me a min to figure this out.....then I looked back at my post..... I was certainly thinking about transmissions when I wrote that!! LOL

[datzenmike]

I have a dirty mind too.

[jrock4224]

Yes d mike when I was under there I saw removing torsion bars wOuld make more room.... I wanted to try it with out first to see if it could be done.... U can but it much easier with pulling torsion bars out..... I didn't so I can had to lift the tranny up on its side clocked a little then twist and I lifted to get the starter bulge up in there..... And trust me I thought about cutting crossmember and making it bolt in bu since I will be removing torsion bars and that crossmember eventually I decided against it....yes the clutch and pressure plate install after tranny was in place was a little intimidating but actually was easy but took a good bit of time to get it all tightened torqued and re checked....as far as what mike was saying about driving angle after making second lower mount mod I removed my carrier shims as it was obvious that it was the high point of my driveline...... U never want a driveline to both incline and decline at the same time..... Anyway two more days on it still

Perfect..... Not sure on the ratios but 2 nd and third feel taller as I stay in them longer and they build power as apposed to the 4 sp feeling like I was over revving.... On the 4 sp I used to shift 1 st , 3rd 4 th as I felt I was too through second very quickly..... On the 5 sp I use 2nd alot and don't skip it

 

MkoltZ figured it was uninternional but when I was typing earlier post everytime I wrote tranny in the back of my mind I was thinking I was opening the flame window....... I like trannys there it's out there ...... Transmissions

[EricJB]

I tend to make things difficult for myself. I moved the motor forward to make room. If I have to take it back out,( and I'm sure I will) I am going to cut the tunnel out, and make it so it bolts or dzus fastens back in.

[EricJB]

Hey Jrock, How does a guy your size fit in a 521? It 's a squeeze for me and I'm barely 6.0.

[jrock4224]

Butt first legs second and I better not have to get my wallet or my phone.....it's a blast once I'm in there but it's definately kinda a nesting doll feel

[jrock4224]

Check my goon thread for front seats placement..... Definately will be roomy like a caddy.....I don't have that option in the 521 and Wayno won't give me a glass rear window ext cab..... Wayno how tall u? Must be bigger with your addiction to ext cabs

[datzenmike]

Anyway two more days on it still

Perfect..... Not sure on the ratios but 2 nd and third feel taller as I stay in them longer and they build power as apposed to the 4 sp feeling like I was over revving.... On the 4 sp I used to shift 1 st , 3rd 4 th as I felt I was too through second very quickly..... On the 5 sp I use 2nd alot and don't skip it

 

 

Here are the old and new ratios

 

4 speed, 5 speed

3.657..... 3.321... 1st

2.177..... 1.902... 2nd

1.149..... 1.308....3rd

1.000..... 1.000....4th

[jrock4224]

Mike if I wasn't a dude I would ask u to marry me....

[Sealik]

Mike if I wasn't a dude I would ask u to marry me....

 

Never to late for another 'swap'............ :lol:

[datzenmike]

:o :D :lol: :rofl: just found this.

[wayno]

Check my goon thread for front seats placement..... Definately will be roomy like a caddy.....I don't have that option in the 521 and Wayno won't give me a glass rear window ext cab..... Wayno how tall u? Must be bigger with your addiction to ext cabs

 

 

I am 6'1" tall, I have been driving the 521 work truck almost daily since 1995, I made the 521KC to have something differant, after I bought that first 720KC, I came to realize that I liked having legroom, and the 521 kingcab was born.

[jrock4224]

I'm 6-7" and it's tough to fit in anything

[datzenmike]

I've 6"-7" and it's tough to fit in anything

[jrock4224]

wow...i wish more 8"-10"... that's bend it in half length

[djpapo]

hi i have a big question i found a 5 speed transmission in a 1986 720 sort bed n i need to know if t can some how make it fit my 1973 620 sort bed

I've been told n seen all the postings  about the 720 transmissions leaning to the side n all the modifications need it

so can i swap the bellhousing so it can bolt in to the L16 in my truck n if the answer is yes pls help me  do i need the driveshaft   

n or anything else i want my truck running already n 5 speed transmissions that fit right in with out cutting n or driveshaft modification are hard to come by thank u 

[datzenmike]

First is the 720 transmission 26" long? If so an L series front case can be put on it and it will fit your '73 without having to shorten the driveshaft. (you may have to mod the rear mount)

 

If the 720 transmission is 31.5" long you can still swap an L series front case onto it but you will need the front half of the two piece driveshaft from a '74 and up 620 to make this work. (the front driveshaft is already shorter) Maybe get the later tranny mount from the 620 as well.

[jrock4224]

i got a 620 two piecer laying around...i love my shorttail...

[DeviousPsycho620]

I believe i have a dogleg in my truck. Is there an easy way to tell? I'm still learning about my Frankintruck. I believe it came out of an 83 200sx.

[wayno]

I believe i have a dogleg in my truck. Is there an easy way to tell? I'm still learning about my Frankintruck. I believe it came out of an 83 200sx.

 

If you have a dogleg 5 speed, that would mean that reverse is where 1st would be on any normal floor shift transmission.

As far as I know, the L block dogleg transmission only came in the 1977-79 200SX, any other year would not be a dogleg transmission.

[DeviousPsycho620]

Ok. No dog leg then. Thanks man.

[Docsis510]

Will this work on a 510??

[datzenmike]

Yes the 720 shorty with a L series front on it will be the same length as the 510's 4 speed. I doubt the rear mount will fit without mods but this sure beats shortening the driveshaft. This gives you in effect a six cylinder or truck transmission.