greenthumb Posted July 17, 2021 Report Share Posted July 17, 2021 Was that 5th gear synchro giving you trouble before? Like Mainer says, that’s an odd one to have go. Not many slammed shifts into 5th. I’d be inclined to run it if it worked before 2 Quote Link to comment
datzenmike Posted July 17, 2021 Report Share Posted July 17, 2021 1 hour ago, mainer311 said: Also, don’t forget: brass synchros use gear oil as friction modifiers to work correctly. That’s part of the reason that these transmissions call for GL4. GL5 oils have extra additives that may affect the rate at which the synchro accelerates. You did. 2 Quote Link to comment
datzenmike Posted July 17, 2021 Report Share Posted July 17, 2021 15 minutes ago, mainer311 said: How did you turn this into an oil discussion? You did 2 Quote Link to comment
datzenmike Posted July 17, 2021 Report Share Posted July 17, 2021 18 minutes ago, mainer311 said: How did you turn this into an oil discussion? You did 1 hour ago, mainer311 said: Having a 5th synchro wear out seems really strange to me though. That would be the least likely one to wear out. Also, don’t forget: brass synchros use gear oil as friction modifiers to work correctly. That’s part of the reason that these transmissions call for GL4. GL5 oils have extra additives that may affect the rate at which the synchro accelerates. 2 Quote Link to comment
Crashtd420 Posted July 17, 2021 Author Report Share Posted July 17, 2021 10 minutes ago, greenthumb said: Was that 5th gear synchro giving you trouble before? Like Mainer says, that’s an odd one to have go. Not many slammed shifts into 5th. I’d be inclined to run it if it worked before I had used the transmission before but at the wrong angle with the z bellhousing... I dont remember having an issue getting into 5th other than having to reach to do it.... But that was over 16 years ago ... Long story short I used a 4spd instead to get back on the road. Then ratsun helped me realize I could actually use my 5spd properly... In order to do it I had to do a bellhousing swap and change the bearing to the smaller size to fit the L series case..... I found one bearing in the center plate split in half but had not completely separated... other than that I though everthing else looked good.. So I replaced all the bearings and put the 5spd in the truck... right away getting into 5th was an issue.... So Yes it's been giving me trouble for a while.... it was never right and I was probably making it worse and probably caused the shift fork to break... 1 Quote Link to comment
datzenmike Posted July 17, 2021 Report Share Posted July 17, 2021 3 hours ago, Crashtd420 said: Next up on the question list is will the 5th gear synchro from the z car 5spd 71b work in my short tail 71b? https://zcardepot.com/products/synchro-transmission-5th-gear-oem-240z-260z-280z This was an '80 and on 5th synchro. Thee were a lot of changes to the 71B in '80. All 720 5th use 32604-E9801 synchro. As does the '80 and up 280zx, '80-'83 S110 200sx, '81 '84 Maxima, '84-'89 Z31 300zx, S12 200sx and pretty much any RWD 71C using truck or car after '86 The 240/260 didn't have a 5 speed but the '77-'78 280z did but not the same part 32604-P0100 and was in the 'first year '79 280zx but changed for '80 to the E9801. All 5 synchros in the 5 speed are the same part so a first gear synchro will work on 5th. 3 hours ago, Crashtd420 said: And last the dumb question..... Does the gear in the back come off if I remove that nut and bearing ? I'm just hoping I don't have to remove everything from the other end of that shaft...... I'm hoping that synchro can replace by just undoing what you see..... Yes once the mainshaft nut is off there is a washer, bushing and a needle bearing the 5th gear hub rides on. Then the synchro. The early 5 speed the mainshaft nut wasn't staked and coud loosen and back off loosing 5th gear. 2 Quote Link to comment
Crashtd420 Posted July 17, 2021 Author Report Share Posted July 17, 2021 (edited) Thanks again for the assistance datsunmike.... Placed my order this morning... I ended up buying the baulk ring and the mainshaft nut and that other one that needs to staked when reassembled... If I'm lucky I'll get the transmission disassembled down to the synchro, ready to put it back together when parts show up..... I still have 2 weeks till we leave.... Edited July 17, 2021 by Crashtd420 1 Quote Link to comment
Stoffregen Motorsports Posted July 17, 2021 Report Share Posted July 17, 2021 Yes, you can remove the rear stacks of gears without removing the shafts from the center plate. Be careful that the shafts do not move from the center plate though. If they do, the thrust washer could move and the tiny ball that locates it could fall, or worse, get sandwiched between the thrust washer and the bearing. I always put a dab of vaseline or grease on that ball (or pin in some cases) to keep it in place during assembly. I'm pretty sure all 5th gear synchros from that era were the same. Remember the broken shift fork? That might have had something to do with the worn 5th gear synchro. Probably not a coincidence. 2 Quote Link to comment
Crashtd420 Posted July 17, 2021 Author Report Share Posted July 17, 2021 5 hours ago, Stoffregen Motorsports said: Yes, you can remove the rear stacks of gears without removing the shafts from the center plate. Be careful that the shafts do not move from the center plate though. If they do, the thrust washer could move and the tiny ball that locates it could fall, or worse, get sandwiched between the thrust washer and the bearing. I always put a dab of vaseline or grease on that ball (or pin in some cases) to keep it in place during assembly. I'm pretty sure all 5th gear synchros from that era were the same. Remember the broken shift fork? That might have had something to do with the worn 5th gear synchro. Probably not a coincidence. I found an exploded view while searching for the part.... Looks pretty straightforward, I'll rent a puller tomorrow and be ready for the new parts to arrive .... Oh and its definitely not a coincidence, probably cracked the shift fork over time trying to get into 5th..... cause and effect.... I should have pulled the transmission out right away but I was so happy to have the 5th gear and it was into the driving season for the datsun..... one thing leads to another and here I am fixing 2 issues instead of 1.... 2 Quote Link to comment
Crashtd420 Posted July 19, 2021 Author Report Share Posted July 19, 2021 Still cant get a good picture of the synchro... I do see flat spots and some damage so I'm crossing my fingers this is the issue..... I was able to get everything neccessary disassembled, now I just need the replacement parts..... 1 Quote Link to comment
banzai510(hainz) Posted July 19, 2021 Report Share Posted July 19, 2021 (edited) crap i just deleded the link i had for the 5 spped sycro repair cobra transmission Edited July 19, 2021 by banzai510(hainz) 2 Quote Link to comment
Crashtd420 Posted July 19, 2021 Author Report Share Posted July 19, 2021 1 hour ago, banzai510(hainz) said: crap i just deleded the link i had for the 5 spped sycro repair cobra transmission All good, I saw cobra transmission, they had full rebuild kits, didnt see just the synchro.... I opted for oem because it was still available, I have been ordering some oem stuff from here.... https://www.nissanpartsdeal.com/ Got the synchro for $57..... 1 Quote Link to comment
Stoffregen Motorsports Posted July 20, 2021 Report Share Posted July 20, 2021 You don't already have the front case glued to the center plate, do you? 1 Quote Link to comment
Crashtd420 Posted July 20, 2021 Author Report Share Posted July 20, 2021 1 hour ago, Stoffregen Motorsports said: You don't already have the front case glued to the center plate, do you? Of course I do.... I had the whole thing ready to go back in, then I didnt like the way 5th was acting.... Luckily I haven't disturbed the front bond, I have a spot on the tail housing I can use a screwdriver to break the bond to get that end off.... I know its risky..... 2 Quote Link to comment
Stoffregen Motorsports Posted July 20, 2021 Report Share Posted July 20, 2021 It will probably be fine. 2 Quote Link to comment
Crashtd420 Posted July 20, 2021 Author Report Share Posted July 20, 2021 43 minutes ago, Stoffregen Motorsports said: It will probably be fine. I'm hoping.... I'll make sure before I bolt the tailhousing on... 2 Quote Link to comment
Crashtd420 Posted July 22, 2021 Author Report Share Posted July 22, 2021 Damn, while the parts did ship they wont be here till Monday..... we leave the following Saturday.... My only hope of success is to disable the truck Sunday and pull the transmission out..... Reassemble transmission monday... Hope the hell I'm correct and the synchro fixes the shifting issue... And stuff the 5spd back in there before the weekend... preferably with some time to test drive before we have to leave..... 2 Quote Link to comment
Stoffregen Motorsports Posted July 22, 2021 Report Share Posted July 22, 2021 Not to sound patronizing or anything, but I wish for a time when problems were that simple. I moved to the country to have the simple life, but the way my business has gone, the problems are anything but. Do a bench test to shift the gears before it goes in, and hell, if you have the rear slip yoke available to plug the tailshaft, you could even fill it with fluid before install. Aside from those issues, what else is there? You got this. 2 Quote Link to comment
Crashtd420 Posted July 22, 2021 Author Report Share Posted July 22, 2021 1 hour ago, Stoffregen Motorsports said: Not to sound patronizing or anything, but I wish for a time when problems were that simple. I moved to the country to have the simple life, but the way my business has gone, the problems are anything but. Do a bench test to shift the gears before it goes in, and hell, if you have the rear slip yoke available to plug the tailshaft, you could even fill it with fluid before install. Aside from those issues, what else is there? You got this. Your not patronizing, I get what you mean.... trust me I prefer life to be without drama but i am not always that lucky.... I just try to take it all in stride..... I'll definitely be bench testing it.... I'm about 95% confident, its the 5% unknown that i hope doesn't bite me in the ass..... Just hoping I'm not creating more work for myself or jinxing myself by pulling the 4spd early.... 2 Quote Link to comment
Crashtd420 Posted July 23, 2021 Author Report Share Posted July 23, 2021 This just figures..... After getting home from work I put the truck in the garage... I was going to give it a check over really quick.. pull the plugs and maybe double check the valve lash in preparation for our trip next weekend.... When I opened the hood I found a broken air cleaner mount.... fun, something else to deal with...... 1 Quote Link to comment
Crashtd420 Posted July 23, 2021 Author Report Share Posted July 23, 2021 Luckily another easy fix.... Few spot welds and back in business.... Just checked the plugs and nothing concerning there so I'm happy with that..... Next up is valve clearance check.... 1 Quote Link to comment
Crashtd420 Posted July 23, 2021 Author Report Share Posted July 23, 2021 Valve check went good, found an old remote starter switch I made, which I used to bump the motor over, that was so much easier than using a wrench... Only 2 out ... 1 intake was .002 loose 1 intake was. 001 tight... Rest were perfect...... 1 Quote Link to comment
Charlie69 Posted July 24, 2021 Report Share Posted July 24, 2021 It is good to see some general maintenance done. Nice work. 3 Quote Link to comment
Crashtd420 Posted July 24, 2021 Author Report Share Posted July 24, 2021 8 hours ago, Charlie69 said: It is good to see some general maintenance done. Nice work. I keep a good eye on everything with how much I drive it.... Knowing I have a long drive coming up I just wanted to make sure .... Pretty confident it will survive the trip without issue but a quick once over doesnt hurt...... 2 Quote Link to comment
Crashtd420 Posted July 24, 2021 Author Report Share Posted July 24, 2021 Got a shipping notification that my parts should be here this afternoon.... so I should have the transmission fixed today... And start the swap back to the 5spd tomorrow...... 2 Quote Link to comment
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