p7x

Ya gonna take a break but I’ll have to open it up and confirm what’s going on and gears

Sucks

Took the half shafts off today and found very little to no play in them. Took them to a driveline shop and they also confirmed the same. Played the shop the videos below and the general consensus was the Diff is in bad shape. thoughts from this community?

Driveshaft installed!! There's good news and bad Good: Acceleration clunk reduced by 30% to put a number to it Clunk seemingly no longer happens on deceleration Shifting into each gear is smoother (unexpected) Taking up on the clutch better aka the clunk doesn't happen when releasing clutch mid speed Acceleration seems somewhat smoother Bad: Still have a noticeable clunk in the rear end under quick acceleration or quick release of the clutch. Overall: The driveshaft (prop) u joint was definitely part of the problem but not the full solution. Also noticed that when I was reversing quickly as part of my testing that there a rumbling noise coming from the rear. Next Steps: Remove the half shaft to check those u joints Play with the differential some more.

Really? I had clunking with the stock diff mount that was worn (thought that was the problem because the diff moved up and down) so I went to the solid mount and it actually made the clunking worse. which is starting to make a little more sense if the diff is the issue, bolting it down with a solid mount would exacerbate the issue...more and more thinking its the diff itself.

Need to swap the dust cover / sleeve from the old to the new shaft to cover the exposed gap then I'll be driving it to see if there is any change in the clunk.

^^^^ Jebus! Mine might not be that bad but maybe not far off. From the video below what to you guys think? I just installed the new driveshaft but haven't driven it yet. Regardless there's still a good amount of play in the diff but is it too much. The play is shown is the movement before the diff starts spinning the wheels. I've been beating around the bush based on what ive read in the community but the bush (Diff) might 100% be the problem.

I've check the bushing, mustache bar, bolts etc and things seem to be in good shape. Honestly starting to worry that my tranny or diff are actually the issue.

So moving the car around in the garage and 1) when backing the car out of the garage and a full second of grinding coming from the rear end while in reverse. This metal grind and moaning noise happens at very slow starts in first as well but this was the loudest i've ever heard it. 2) forcing the clunk to happen in 1st gear and then shifted into reverse and the clunk happen with no power going through the driveline. WTF

Driveshaft (prop) is going in this weekend and honestly am only at 50% belief the could be the issue. The other 50% makes me think its the diff itself.... Hunt continues.

Hey man, ya be good to meet other owners.

New drive shaft (prop) is ordered and last night went through the whole back end and tightened everything to spec. Something I should of done from the beginning ... lesson learned. Pretty much everything was spec except the inner and outer lower control arm bolts those were pretty loose. gonna take the car out today to see if tightening things helped at all. Once the new driveshaft is in I’ll update the thread.

Hello Everyone, In May I bought a 1978 280z 5 Speed with 250,000 miles on it. Been in California for 41 years until now, California spec car. I've always loved the S30s and been wanting one for years. My plan this year is to get it into very good mechanical shape and over many years to come to slowly restore / mod it. Thanks in advance for your help / advice.

Ya there’s a good shop near by that I’m gonna call this week talk to them and see what they’ll charge. I feel I could do a driveshaft (prop) swap just no clue about the balancing of the driveshaft (prop)

Ya just to be clear I’m talking driveshaft(prop shaft) between the tranny and diff, not half shafts. From what I can find from multiple sources is after 75 you can’t replace the u-joints on the driveshaft easily. In my hunt I’ll probably take the half shafts off as well to inspect them.

Research tells me that you can't replace the U-joints or not easily anyways. Nissan changed them in 75 and it looks like if I were going down the route to fix it i'd have to replace the whole driveshaft...

Started a new thread on my hunt for the clunk.

Hey Everyone, So I replaced my front diff mount with a solid unit and now the clunk in the car is louder more pronounced than before. Worn diff mount might have contributed but now with the solid mount its exacerbated the clunk. I'm new to the S30s so with all the experience on this forum I was hoping you all could help me in determining if there is too much play in the drive line and what might be the source of the "Clunk". Assuming the old rubber diff mount absorbed some of teh slack and now with a solid unit the play in the driveshaft is now more pronouced. Videos below showing some play in the driveshaft U-Joints at the tranny and very little play in the U-Joints at the diff. Based on the last video I think the driveshaft -Joint at the tranny is potentially the source of the clunk. ***REPLACED: 1) transmission mount (oem replacement) 2) front differential mount (solid unit) 3) Half shafts checked and U Joints are in good shape transmission to driveshaft play Driveshaft to Diff play Driveshaft twist and clunk I'd appreciate your thoughts / advice

Ya I was tracking but replaced it as it was simple to do. UPDATE / Another lesson: The clunk is louder more pronounced than before. Worn diff mount might have contributed but now with the solid mount its exacerbated the clunk. Time to dive into the thread posted above and find the next item that needs tightening / replacing.... Thanks again for chiming in.

Yes they were... were as in I made a 3 foot breaker bar and that did the trick. Loud snap and I thought I broke the head off the bolt but once got about a quarter turn they were loose and hit them with the impact and came off / out no problem. Installed the new Mount easily and strap easily. Thanks for the replies and info.

Gents you are bolder than I am. Slowly building my skills and know how with basics tools. Was hoping the mount swap would fix the clunking in the rear end. Just got the car and This year I just need to keep it in running / driving condition until next year when I can actually start restoring it. Thanks for the replies. I’ll update the thread on how things go.

That might have to be the next step. Because in wrenching on the bolt head vice the nuts I'm worried about applying that much pressure

Stock front diff mount - the long bolts that bolt the mount to the diff with the nuts on top of the diff and the head of the bolts facing down. The mount was toast so I torn it apart to access the heads on the bolts

Hey all, The search function on here crashes on me constantly so pardon if there's a thread on this but didn't find it. I'm replacing the Diff mount with a solid billet unit on my 78 280z but the mount bolts in the Diff will not break. I've used a smallish breaker bar and my 18v Impact and I cant break the torque on the bolts. I've used my larger torque wrench to see how much torque i'm putting on them and its showing im put over 65 lb/ft and the aren't moving. I believe the torque spec for the bolts is 58 lb/ft and ready to get a impact wrench but concerned ill snap the head right off the bolts. Any tips / tricks / advice for a new S30 owner?