78 620 5sp....for my 521 need advice...

[jrock4224]

So this weekend after storing my sweet deal 5 sp tranny for close 6 months on a pallet with my l20... i was moving it with the forklift about 3 feet...raised it 4 inches off the ground, stopped to repostion my motor on the pallet better, heard a thud...walked to the other side and the tranny that was standing was now laying on its side on the ground...stood it up to find the input tail shaft seal...folded in against the splines...pulled the seal out to find the seal housing of the tranny tail haft folded in....tried to gently bend it back but it was already split...ended up removing over half the sealing surface of the tail shaft... now theres nowhere for the tailshaft sela to seat against.. so now i am asking for remedy's... I got a buddy that think's we can fix it even though I don't have all the pieces...so any suggestions i thought about buying a broke tranny and swapping the housing but not much of a tranny tech so still weighing my options

[jefe de jefes]

Install a new seal and build up some jb weld on the outside?

[jrock4224]

i will post pics soon..

[hessianben]

Motivated had to deal with a situation like this- he may have some tips

[jrock4224]

 

 

man i am so pissed the thing was on pallet racking 20 feet in the air never had a issue but the one time its 4" off the ground, boom... snapped off the corner...i wish it didnt shatter into tiny pieces could tigged it back in put a seal in it and smeared some jb on the outside to assure a seal...so is it feasable to swap out the tail shaft of a nother tranny, theres one on cl thats broke but i am sure its not casing issue like mine...i will contact motivated...

[jrock4224]

checked out motivated thread and i wish my tranny looked like that... thats a easy fix .. little heat till bead little worry... mines a friggin mess.. i think the best way is to swap out the tailshafts housing...was told wayno is a tranny guru ... sent him a message abou tit and to se if he had any recomendations...at least motivated could punch his brother for not catching the tranny....i had to punch myslef in my already fucked up face.. last weeks hit list... cresent wrendch to eye socket by employee monday...three 12' 2x4s smaked me in the forehead then drug down my face wednesday.. and saturday i f- up my best score...my 200.00 l20, 5 spd, and full 620 front suspension...i hope i can fix this damn thing...

 

and will some one verify from the pics its a 620 trnasmission... i bel;ieved him sinc the rest of the 620 was all there...i can take a better pic if needed...

[datzenmike]

It's consistent with a '77-'79 620 but also the same years 280z. If it only has the reverse light switch it may be a non California 280z.

 

If from a 620 there were two different ratios '77-'78 (mid ratio) and the '79 (wide ratio).

 

The old one was flush

 

 

 

The new one was thinner perhaps to have the seal touching further back inside the tranny to put on an unused portion of the spline. I've seen Chev front timing seals this way to put them on a fresh sealing surface.

 

You could carefully hammer it into place, degrease the exposed part and JB it. The drive shaft has a dust shield that covers this area so just enough JB to cover and support it.

 

 

 

 

 

You could try this to keep you going while you look for a replacement tail stock or tranny replacement. It must be a 5 speed from a 620/280z or 810 made before 1980. A 4 speed will not work.

.

[wayno]

Hey there jrock4224, I found the thread, I have at least one tailshaft from a 1980-86 long shaft 5 spd. transmission, maybe there the same as I can bolt up a diesel case to a 620 5 spd. but it does me no good as the 620 5 spd. tranny has useless gearing for the SD22-25 diesel engine. How about it "KINGRAT", will the 1980-86 longshaft tailshaft bolt to the 620 tranny, this is something I have had no need to find out. I also have a 620 5 spd. longshaft tranny with the 1981-82 diesel case bolted to it, that can be removed and a L casing can be put back on. wayno

[jrock4224]

you talked with my friend frank , phixius... about some gearing and he thought you had built a 5 sp that used the stock driveshaft and came through the floor in the stock location...really i am just looking for a solution.. my fabricator buddy swears he can build it back then pull the case off and machine the seal bore... seems like a lot of work, its a 78 620 trans at least i was told thats the vintage by the guy i bought it from it came with a l20 and front suspension off same truck and its a disc brake front end so i figure its late 70s....its all going in my 521 , i have limited 620 knowledge so i m not muh help... i do know it wont work this way... i think the most permenent fix is to swap cases... but is rank right in ssaying you built sme morph tranny that uses stock shifter location and a factory drive shaft... sounds impossible... but i am listening.. maube he jus punked me, and i look like a bigger idiot for suggesting thats doable as apposed to breaking my perfectly good 5 sp.... doooooaaahhhh

 

ps state capital olympia freaking wa..+.+ that last part was my 18 mo old daughter typing

[motavated]

My trans was like that. But it was not that much broken of... The guy added a bronze donut in the center and filler it in. Then I took tig and I filled it in from the inside. Then I grinder it down smooth. You have to take off the tail housing to do it no matter what.

 

remove the bolts from the center of the transmission, and the all the sensors and the shifter return spring. Then it comes out. Easy... Trust...

[jrock4224]

awww motivate spounds easy....um is there a thread with pics... i saw one you made about it broken in fact i posted on it to bring it back to the top in parts ... so i could reference it

[wayno]

If you use a long shaft in a datsun 521 pickup you will have to relocate the shifter hole, the driveline will have to be shortened and the tranny mount has to have something done to it I beleave, and the bench seat might have some issues, you might be able to use a notched 620 seat, and have fun getting it in there without moving the engine. My 1971 datsun 521 pickup has a normal truck 5 spd. in it and it has out lasted all the 200SX 5 spds.(3 of them) combined, and it bolted right in to the truck with no mods. But I have to say that when I bought the truck it had the 200SX tranny in it, so any mods. to the tranny mount and driveline yoke were done before I owned it. OK, here we go again. What you need first is a 5 speed out of a 1984-86 nissan 720 regular cab short box 2 wheel drive pickup(4X4s don't have the speedo drive in the trans.) with a napZ engine, the second thing needed is a 1980 datsun 720, L20B engine 5 speed longshaft transmission front casing with the front cover and all shims and clips, if unable to get the casing then the whole tranny. I did it differantly, I went to the wrecking yard that had both trannys and pulled them both and put what I needed together and paid for one transmission. You might be able to use the front casing off your 620 5 speed, I have never used it because I have no use for the 620 longshaft gears as they are unusable with the diesel engine, and the 720 diesel is the only truck I have left that uses a longshaft. The 1984-86 shortshaft 5 spd. has a larger cluster gear bearing on it that has to be pulled off and the smaller 1980 cluster gear bearing needs to be put in its place as you will be using the 1980 front case, in my opinion you should put a new bearing on the front cluster gear shaft since it is out there in the open, then it all needs to be put back together. If you go with the shortshaft then it doesn't matter that you ruined your longshaft tail housing as it is not needed, I think the cases are the same, as I said earlier, I have 620 transmission gears bolted to a 1981-82 diesel casing. I will help you put it together if you come down here. But we would need to talk before you buy the parts. wayno

[DanielC]

I did put a long 5 speed in a 521 pickup.

Shortened the front half of the driveline.

Had to have a slip yoke on the transmission end of the driveshaft to match the transmission.

Shortened the rear transmission mount.

Moved the hole in the floor back for the shifter.

The shifter did not hit the bench seat, it was just closer.

Used a speedometer cable from a 240 Z to reach the speedometer pinion on the transmission.

Did not hook up the neutral, or third gear switches. I did hook up the reverse light switch.

 

I used the "rally" 5 speed transmission, this transmission had about a 3.3 to 1 first gear ratio.

The stock 521 4 speed uses a 3.6 to 1 first gear ratio.

[jrock4224]

If you use a long shaft in a datsun 521 pickup you will have to relocate the shifter hole, the driveline will have to be shortened and the tranny mount has to have something done to it I beleave, and the bench seat might have some issues, you might be able to use a notched 620 seat, and have fun getting it in there without moving the engine. My 1971 datsun 521 pickup has a normal truck 5 spd. in it and it has out lasted all the 200SX 5 spds.(3 of them) combined, and it bolted right in to the truck with no mods. But I have to say that when I bought the truck it had the 200SX tranny in it, so any mods. to the tranny mount and driveline yoke were done before I owned it. OK, here we go again. What you need first is a 5 speed out of a 1984-86 nissan 720 regular cab short box 2 wheel drive pickup(4X4s don't have the speedo drive in the trans.) with a napZ engine, the second thing needed is a 1980 datsun 720, L20B engine 5 speed longshaft transmission front casing with the front cover and all shims and clips, if unable to get the casing then the whole tranny. I did it differantly, I went to the wrecking yard that had both trannys and pulled them both and put what I needed together and paid for one transmission. You might be able to use the front casing off your 620 5 speed, I have never used it because I have no use for the 620 longshaft gears as they are unusable with the diesel engine, and the 720 diesel is the only truck I have left that uses a longshaft. The 1984-86 shortshaft 5 spd. has a larger cluster gear bearing on it that has to be pulled off and the smaller 1980 cluster gear bearing needs to be put in its place as you will be using the 1980 front case, in my opinion you should put a new bearing on the front cluster gear shaft since it is out there in the open, then it all needs to be put back together. If you go with the shortshaft then it doesn't matter that you ruined your longshaft tail housing as it is not needed, I think the cases are the same, as I said earlier, I have 620 transmission gears bolted to a 1981-82 diesel casing. I will help you put it together if you come down here. But we would need to talk before you buy the parts. wayno

 

um my brain hurts...so if i fix this tail housing i have,(i believe long tail shaft) i will take a better pic tomorrow, then i wont be able to use the stock bench due to shifter location...thats not good i am 6-8" and use a severally worn out seat just fit in my girl...and dont wanna go buckets. sorry daniel c covered it...hmmmm anyone got a long tail housing they wanna part with

[wayno]

I am not saying it can't be done, as DanielC said, he did it, if your shifter stick hits the seat, find another one that is tilted forward or heat it up and bend it forward. The 620 longshaft trannys are good, there just hard to get in and out of a 521 and early 620 pickup, otherwise everyone would do it. I do have a long tailshaft for a 1981-86 5 spd. that I would trade you strait across for, it's just scrap metal to me. But I do live in vancouver wa. and I am not positive it will fit a earlier 620 5 spd. even though they look basicly the same, but the later 5 spds. have a 5th gear, reverse lockout and I don't know if the 620s 5 spds. have that. wayno

[jrock4224]

i think the seat interference wont be too much of a issue since i am cutting the frame down to get some more room..i got my junk yard connection searching those parts...probably end up swapping tail section even though i would love to have that morph tranny that fits in stock location... i am super anal...I said i am anal not into anal, so wayno, i will send you a pm about the tranny options as soon as my wrecking yard guy responds with what he has and how much..or can come up with...i think i understand your post and comprhend it after reading it a few times... sorry i am a dumb mini trucker... takes me a bit to sink in..

[jrock4224]

so wayno is "datzunking" the guy to ask if i can put the 720 short shaft tail section on my 620 bell? or i guess at this point i would experiemnt if i had the 84-86 tail section... the funny part is i have the l16 and 4sp. sold as soon as i pull it and i havent done a thing but move the motor and tranny around for the last 6 months... i got a jet boat to build... i aint got time for this....by spring i got have my 429 ford in my new 74 eliminator...oh and paint that eliminator and sell my old hull?

 

any one looking for a ford big block ready jet boat 1978 sundance..hull pictured is the one i am sellingafter swapping..

 

 

 

less motor and a different interior...oh yeah and a different trailer thats singel axle...( i cant let my brand new trailer i just finsihed powdercoating and dialing go with my old hull..) the hulls are almost identical so i wont need to mod the trailer to change hulls...

 

now back to my tranny problem... sorry just anxious and photobucket was open

[datzenmike]

How about it "KINGRAT", will the 1980-86 longshaft tailshaft bolt to the 620 tranny,

 

It must be a 5 speed from a 620/280z or 810 made before 1980. A 4 speed will not work.

.

 

Answered.

 

But yes it will bolt up but from '80 on the speedo is differently bolted and mounted and the 620 speedo won't work in it. You are stuck with whatever comes in it including speedo error.. Also the '80 and newer have a reverse check sleeve that the earlier 620's don't have. It's function I haven't completely figured out but was told that with it, you can't accidentally shift into reverse while the truck in in forward motion. I have one or two trannys with it but haven't gotten around to investigating this yet. How the reverse check sleeve interacts with the reverse gear or linkage I don't know. Weather it will work or interfere with a earlier tranny is unknown.

 

A 620/280z or 810 before '80 will work fore sure. Anything else is a maybe.

*If only the tailstock is damaged and this is a good 5 speed, the easiest thing is to clean and install the seal. JB around it. Second easiest thing is to replace the tailstock. You could try a 720/200sx or 280zx after '80 to see if it works. Bolt it up and select all gears and turn the input... see if the output spline turns. If it does shift into all gears your good to go.

 

____________________________________________________________

 

Yes the long tail is about 6" longer so the shifter will be about this much further to the back and the drive shaft and rear tranny mount altered, but it's a one time investment and if you have to change the tranny for another there are lots of long shaft ones that will now drop right in.

 

Yes there is a short tail 720 5 speed that can be converted over with an L 4 or 5 speed front case to allow it to work on an L series motor. The front case off your broken 5 speed will work but the rest of the tranny is a loss and you have to find one of these shorter ones. To be clear: In order to use the short tail stock tranny you have to use everything but the front case. Changing just the short tail stock won't work as the longer spline will just stick out of it 6".

 

(see * above)

[jrock4224]

I had no idea you were refered to as the king rat till i looked and you powned me and told me so .. sorry i will do better at recognizing the obvious... so will the 80-86 long tailshaft move the shifter back to the stock location or is it just a option...to fix my situation...i would entertain the long shaft later model tranny if it moved my shifter forward but if its the same i dont care either would work... sorry I asked redundant question...

[datzenmike]

Your 521 has a 4 speed that is about 26" long. Ideally, a 5 speed of this length would just drop in and very little would need changing.

 

The 620 5 speed that is damaged is 31.5" long. So the drive shaft will need shortening and the shifter will be about 6" further back. Just measure back 6" on your trans tunnel and see where the new location will be. Will it clear the seat ok?

 

I assume you want to keep the 620 5 speed and use it?, so repair or replace the tail stock.

 

Note: The 521 is unique in that the drive shaft spline is bolted onto the transmission output spline ans has a flange on the end. This flange bolts to a mating flange on the drive shaft. The drive shaft can be unbolted and the tranny removed with the spline attached.

 

This is your 4 speed with flange output spline bolted on.

 

 

The flange can be unbolted and will fit the 620 5 speed transmission but the hole where the nut is now will leak oil. A 40mm freeze plug will fit to seal it up.

 

 

Now continue to shorten the rest of the drive shaft as you normally would.

 

I am............... The KING.

 

 

 

 

 

.

[jrock4224]

and that my friends is why he is the king... mike i am your beotch... thanks ... i was trying to see if waynos morph tranny with short tail would work on my 620 tranny bell... so basically if i source the short tail section gears and all an bolt to (What you need first is a 5 speed out of a 1984-86 nissan 720 regular cab short box 2 wheel drive pickup(4X4s don't have the speedo drive in the trans.) with a napZ engine) and bolt it to my 620 front half bell and i will have a stock lengthish transmission thats a 5 sp, that comes through the floor in stock location..as far as the flange drive shaft, I have the stock 620 driveline it came with my l20 and sorts.. so i have a factory output yoke...and eventually I am gonna go to a one piece drive shaft even if the stock length two piecer drive shaft works...i will run the two piecer till i find a shop that isnt gonna shove a drive shaft in my rear for a grand...I have gotten a couple of quotes one 850 the other 200 clearly i am a little nervous being such a price descripency.. i had one built for a old mazda i had, and i paid 250 back in the late 90's.... if i can source the late model 720 tranny i will go that way ... i like where my shifter mainly cause i am gorilla tall....but if i cant source that model i will find a 5sp tail shaft to swap on ...i never have seen a 521 with a napz engine swap...any reason... ,ost epople just skip right to fuel injection...

[datzenmike]

Here's one of the short 720 transmissions. It could have been made by swapping an L front case on or may be stock from an L powered '80 710. (if they had them)

 

 

Here's mine from an '83 4X4 and has the Z series bolt pattern

 

 

 

jrock, would you humor me and measure the 521 tranny length from bell to the end of the aluminum case for me when you get a chance?

.

[jrock4224]

ok i am on it ... you gonna compare the over length of the top tranny to my 521 4sp. ... do u want a length of front face to the shifter too? that would tell me if it hits the holes in the factory location.....

[jrock4224]

26 and a 1/4ish....I will get a exact measurement since phixius wont let me use a forklift to pick up his truck so i can measure it....

[jrock4224]

26 inchs...plus or minus 1/8....in the truck its hard to get a good measurement...