sick620 Posted January 24, 2016 Report Share Posted January 24, 2016 Datsun Mike probably has an answer. I just swapped trannys in a truck. The truck has a l20b in it. Not sure of year. Probably a 76-78 620 l20b. It had a blown up 4speed in it (long tail). We got a Longtail tranny at junk yard out of a 78 kc. Not sure if it was original to that truck or not. Anyways when we swapped trannys we left the flywheel, clutch, pressure plate un touched, we used our fork, collar, and throwout bearing on our tranny on the replacement tranny. We went and purchased a new slave cylinder for a 78 620, maybe a 79 620.dont recall which..... Well the truck starts and runs in neutral, but when you press clutch won't go in gear. As if the throwout bearing doesn't hit pressure plate, like it's not long enough. Did I need the collar that came with this tranny? Fork? Possible our slave cylinder doesn't have a long enough rod? I bled the shit out of the system, and the fork moves what looks to be the full range of motion that the slave cylinder is capable of. Ideas? Quote Link to comment
Pacific coast Datsun Posted January 25, 2016 Report Share Posted January 25, 2016 I believe the TO bearings are transmission & or clutch specific. Meaning...use the TO bearing that came with the transmission. Quote Link to comment
john510 Posted January 25, 2016 Report Share Posted January 25, 2016 Does it go into gear if the motor ISNT running ? Quote Link to comment
datzenmike Posted January 25, 2016 Report Share Posted January 25, 2016 Datsun Mike probably has an answer. I just swapped trannys in a truck. The truck has a l20b in it. Not sure of year. Probably a 76-78 620 l20b. It had a blown up 4speed in it (long tail). We got a Longtail tranny at junk yard out of a 78 kc. Not sure if it was original to that truck or not. Anyways when we swapped trannys we left the flywheel, clutch, pressure plate un touched, we used our fork, collar, and throwout bearing on our tranny on the replacement tranny. We went and purchased a new slave cylinder for a 78 620, maybe a 79 620.dont recall which..... Well the truck starts and runs in neutral, but when you press clutch won't go in gear. As if the throwout bearing doesn't hit pressure plate, like it's not long enough. Did I need the collar that came with this tranny? Fork? Possible our slave cylinder doesn't have a long enough rod? I bled the shit out of the system, and the fork moves what looks to be the full range of motion that the slave cylinder is capable of. Ideas? Correct. The old release bearing collar goes on the new transmission. Did you put a new bearing on the collar? Clutch slave should move 1.18" of travel. One inch is fine. What was the problem with the old 4 speed???? What was it doing? Was truck stored outside without the old transmission on it, for a long time between transmission swaps? 1 Quote Link to comment
sick620 Posted January 25, 2016 Author Report Share Posted January 25, 2016 We pulled the tranny at the junk yard, and it sat for about a week or two before we installed it in our truck. We pulled our old tranny and installed this one all in the same day. So no sitting. We sat the 2 trannys next to each other, then swapped the complete throwout bearing assembly from our old tranny to the new one (bearing, collar, and fork). Never separated bearing from collar or anything. The problem with old tranny was that one of the tabs that holds shifter in with the shifter bolt was busted off, someone tried driving it like that for a while and messed up synchros, as well as it would get stuck in gear and wouldn't come out. We drove it a while with a bolt snugged into the other tab with a bolt on each side so the shifter had something to get leverage on. It drove. and clutch did its thing correctly, it was just super frustrating when it got stuck in a gear. Slave appears to have full range of motion. Havent measured, just eye balled. Quote Link to comment
datzenmike Posted January 25, 2016 Report Share Posted January 25, 2016 You say the tranny would stick in gear? Ever parked on a hill in gear engine off and tried to take out of gear without using the clutch??? Very difficult because there is a load on the gears. Also a dragging or rubbing clutch disc will wear out the synchro rings or grind when shifting. Was it hard to shift???? Quote Link to comment
sick620 Posted January 25, 2016 Author Report Share Posted January 25, 2016 No it was easy to shift. And it only stuck in gear sometimes. If I remember right only 2nd gear. It shifted as it should. Quote Link to comment
sick620 Posted January 25, 2016 Author Report Share Posted January 25, 2016 Now when you press the clutch in it doesn't feel like the pressure plate ever even makes contact with the throwout bearing. Quote Link to comment
sick620 Posted January 25, 2016 Author Report Share Posted January 25, 2016 It didn't feel like load from the clutch was what was getting it stuck in gear, it felt like broken internals in the tranny. You'd be driving in second, come to a stop, press and hold clutch down. Truck would idle fine and roll backwards if there was a hill or incline of any kind and you couldn't get it out of gear without really applying force to the shifter, a lot of force. But if you came up to the stop in 3rd or 4th, it would come right outta gear no problem. For all intensive purposes, if we had just drove the truck in 3rd and 4th and reverse the tranny was operating perfect. Quote Link to comment
datzenmike Posted January 25, 2016 Report Share Posted January 25, 2016 Well then everything seems like it's correct. If the clutch arm is moving then the clutch should be releasing. What happens if in gear and you try to start the engine??? Quote Link to comment
That4doorKiD Posted January 25, 2016 Report Share Posted January 25, 2016 Yeah sorry man you're probably gonna have to experiment with this yourself cause people always give fuckn different and mixed answers. Anyways, Mine 510 uses only the OE bearing that matches to my clutch/pressure plate and I put the fork+collar on that is OE from my tranny I had a problem like you once when I put the wrong/shorter collar, you need to lengthen you slave rod. I just added a socket that fit in there. But NOW I have the correct set-up what I told you above. Just improv cause if you'r like me cause I really hate taking out my transmission, done it about 5 times and gonna do it again this week sadly Quote Link to comment
sick620 Posted January 25, 2016 Author Report Share Posted January 25, 2016 Mike, if you start it in gear it lurches forward like it should. Except it Doesn't matter if clutch is pressed in or not...4doorkid, that's a good idea for a temporary fix. Quote Link to comment
sick620 Posted January 25, 2016 Author Report Share Posted January 25, 2016 And john510 it shifts smooth and normal when truck is off Quote Link to comment
datzenmike Posted January 26, 2016 Report Share Posted January 26, 2016 To make it simple, what Nissan did was for all the different pressure plate heights they had a matching release collar. This keeps the clutch arm and the slave always moving through the same position. Yes in a pinch, and if the difference isn't too great the slave push rod length can be altered but now the arm (in your case) is farther back and could bottom against the transmission outer case. There's no substitute for the correct collar length to match the pressure plate height. 1 Quote Link to comment
toylet Posted January 26, 2016 Report Share Posted January 26, 2016 I just dealt with this same problem last night...turns out when I was joining the transmission to the engine, i used a bolt to get the case to meet up to engine which jammed the input shaft back into transmission. So now I have transmission out of car and it only moves in neutral.so time to open it up and see. Quote Link to comment
banzai510(hainz) Posted January 26, 2016 Report Share Posted January 26, 2016 above L20 620s all had the same T/O bearing and sleeve I bet. You re bleed the slave cylinder??????? and 4 door kid just should use the stock 510 stuff.Pretty simple really Quote Link to comment
sick620 Posted January 28, 2016 Author Report Share Posted January 28, 2016 Yeah we re bled the system with a brand new slave cylinder after everything was put back together. The slave cylinder moves a lot, and so does the fork Quote Link to comment
banzai510(hainz) Posted January 28, 2016 Report Share Posted January 28, 2016 I would think you grabbed the same stuff from the other truck. maybe the slave rod is a different size?????????? I dont know what you have or took from the last vehicle to the newer one. compare the parts photos I guess and go from there compare the slave cylinder rods Quote Link to comment
cruznude Posted January 29, 2016 Report Share Posted January 29, 2016 Iknow, that I grabbed one off another truck not thinking much about it, and when I started up the truck for the first time, I also recall having shifting issues. so looking through all the parts I came across another slave cylinder and put it on and I guess it had a longer rod and it all worked good after that. 1 Quote Link to comment
sick620 Posted January 29, 2016 Author Report Share Posted January 29, 2016 So today I adjusted clutch pedal and now it works fine. Engages about half pedal. Now I'm gonna have to post a thread regarding wiring problems haha. Baby steps... Thanks for helping me try to figure it out.. Quote Link to comment
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