nevada 620 Posted June 21, 2013 Report Share Posted June 21, 2013 I am trying to find the right transmission to change my short 4-speed 620 to a 5spd, I have read the old threds and from what I gather the car transmission has a wider spread between the gears plus the extra gear. I have found 200SX and 77-79 510 transmissions but they measure about 31' long will these bolt in and what mods are needed? also does anyone have or know of any closer to Sac. everything I have found is way north and most guys wont ship. Quote Link to comment
yochase Posted June 21, 2013 Report Share Posted June 21, 2013 I just put a five speed out of a 79 620 in my 74. Quote Link to comment
bananahamuck Posted June 21, 2013 Report Share Posted June 21, 2013 I think if you have the front driveshaft off a longtail 620 the long tail fits right in,,,,,,,,, i think... (disclaimer) not a 620 guy. Don`t rule this out either,, not as complicated and scary as it looks.. http://community.ratsun.net/topic/28473-how-to-put-together-a-shortshaft-5-speed-for-a-l20b/ Quote Link to comment
datzenmike Posted June 22, 2013 Report Share Posted June 22, 2013 The '73 has a 26" long 4 speed and a proportionally longer front driveshaft. '74 and on 4 and 5 speeds are 31.5" long and with a proportionally shorter front driveshaft. So get a '74 and on 4 or 5 speed and the proper shorter front driveshaft and you're in business. I don't know if the '73 rear mount and cross member can be turned backwards to fit the longer 4 or 5 speeds or not so get the cross member from the later 620 as well just in case. The hole in the floor for the shifter may need to be enlarged to the rear slightly also. Keep your clutch release bearing collar, it's matched to your current pressure plate, but replace the bearing. Just clip it to the 4 or 5 speed clutch arm. Quote Link to comment
619brosbulletside Posted June 22, 2013 Report Share Posted June 22, 2013 I got a 5 speed out of the 280 from the junkyard bolt right on... Just swap the speedo n backlight Quote Link to comment
nevada 620 Posted June 22, 2013 Author Report Share Posted June 22, 2013 thanks for the help is the clutch assembly and throw out bearing the same from the 4-speed to the 5-speed, If I order the 5-spd rear mount will that make up the off set? I found a trans in Fresno yesterday but it has no rear mount, so if I have to I think I can modify the rear mount to fit, the drive line will be no problem I'll just chuck it up in the lathe and shorten it. Thanks for all of the help..... Quote Link to comment
datzenmike Posted June 22, 2013 Report Share Posted June 22, 2013 Clutches don't care what transmission you use. The clutch and release bearing and release bearing housing (or collar) that holds it, are matched to and part of the clutch assembly and must be kept together. The only other connection is the splined input shaft on the transmission and all L series 4speeds (there are at least 3) or 5 speeds (there are at least 4) are the same. Quote Link to comment
nevada 620 Posted June 22, 2013 Author Report Share Posted June 22, 2013 cool that works, i will let you know how it goes I'm looking forward to having my little truck back running again. I found the truck in Carson city sitting in a side yard I had one when I was in high school I gave the door a rattle and the lady told me it was bought new by he r husbands father and had been sitting there since 97, when I asked if she was interested in getting rid of it she said if I can get it out of there I could have it..... really I didnt even hesitate it was pretty strait I figured even if it didn't run its still a score. I drug it home and started to take inventory the bed was full of leaves when I cleand it out it was cherry not one dent on the bed or tail gate when I started nosing through the burnt up interrior I looked at the speedo holy crap really no way 37,000 miles!!! na this cant be right the nissan muffler was still there along with all of the original cloth hoses hmmm ok I look some more and duck under the bottom and its spotless. To make a long story short there was tons of recipts in the glove box and everything jives, so with the way it runs and the way the valve train looks when I adjusted the valves I have to believe it. I love it whe you get a good score. Quote Link to comment
datzenmike Posted June 22, 2013 Report Share Posted June 22, 2013 The '73 has a 26" long 4 speed and a proportionally longer front driveshaft. '74 and on 4 and 5 speeds are 31.5" long and with a proportionally shorter front driveshaft. So get a '74 and on 4 or 5 speed and the proper shorter front driveshaft and you're in business. I don't know if the '73 rear mount and cross member can be turned backwards to fit the longer 4 or 5 speeds or not so get the cross member from the later 620 as well just in case. The hole in the floor for the shifter may need to be enlarged to the rear slightly also. Keep your clutch release bearing collar, it's matched to your current pressure plate, but replace the bearing. Just clip it to the 4 or 5 speed clutch arm. Should have mentioned that this is all related to the 620 4 and 5 speeds from later years. There are several other 5 speeds that are available but these are the most common and easiest as they were used in the 620. Quote Link to comment
]2eDeYe Posted June 22, 2013 Report Share Posted June 22, 2013 cool that works, i will let you know how it goes I'm looking forward to having my little truck back running again. I found the truck in Carson city sitting in a side yard I had one when I was in high school I gave the door a rattle and the lady told me it was bought new by he r husbands father and had been sitting there since 97, when I asked if she was interested in getting rid of it she said if I can get it out of there I could have it..... really I didnt even hesitate it was pretty strait I figured even if it didn't run its still a score. I drug it home and started to take inventory the bed was full of leaves when I cleand it out it was cherry not one dent on the bed or tail gate when I started nosing through the burnt up interrior I looked at the speedo holy crap really no way 37,000 miles!!! na this cant be right the nissan muffler was still there along with all of the original cloth hoses hmmm ok I look some more and duck under the bottom and its spotless. To make a long story short there was tons of recipts in the glove box and everything jives, so with the way it runs and the way the valve train looks when I adjusted the valves I have to believe it. I love it whe you get a good score. I think pics and a project thread are in order. :D Quote Link to comment
datzenmike Posted June 22, 2013 Report Share Posted June 22, 2013 I think so..... Quote Link to comment
Janksun Posted June 22, 2013 Report Share Posted June 22, 2013 Pics or it didn't happen. Also nothing wrong with the 4 speed. Have one in my truck and I can do 80mph just fine. And it's not too loud either. Idk if gear ratios for 73-75 differ though. Quote Link to comment
datzenmike Posted June 22, 2013 Report Share Posted June 22, 2013 You'll likely go faster in 4th than 5th. All standard 620s have a 4.375 rear end except the 4.11s in the '79. It may sound like it's going to blow up but the L20B is red lined at 7K. For the above 4.375 axle, that's 112 MPH. 6k is 96 MPH, 5k is 80 MPH. NOTE this is on stock 23.65" tires. If you are like most and run say a 195 75R14 then even higher... 7k @ 121mph 6k @ 104MPH 5k @ 86MPH 4k @ 69MPH Quote Link to comment
nevada 620 Posted June 23, 2013 Author Report Share Posted June 23, 2013 ok I will get some pcs together for all ifI can figure out how to get them attached. my trans should be here next week and Im looking forward to the switch to a 5 speed. Quote Link to comment
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