not sure if this should go in technical

[Nizmotastik]

im in the middle of buying a 280zx from this guy for $500. Its a really good deal since the engine is running really well. theres a few rust spots but i can fix that. theres 1 small problem with the car tho. When you shift theres kinda of a clunk from the back(i think). When you clutch in and shift its fine, but when you let go of the clutch, it makes the clunk noise. wut do you think it might be? would it be a serious problem or does it just need more transmission fluid?

ps: i know this is the 240sx forum, but i think the transmission should b aabout the same on both and i cant really find any good z car forums.

[Nizmotastik]

i just checked out the z car forums on the board and its totally dead. no posts at all.

[psyclone69]

I have this same type of clunkng in my 240, did you ever figure out what it was?

[leper421]

For the 280zx it has something to do with the differential, mounts I think. VERY common problem

[psyclone69]

Does anyone know about this problem with a 240sx?

[AunVoh]

it's the u joint must likely, replace it and you'll be fine

[psyclone69]

How hard is a ujoint to replace?

[AunVoh]

easy, and cheap

[psyclone69]

Where might I find instructions? I looked at the autoparts store for a chiltons guide for a 240, and can't find one, how do I check the u joint?

[89sxRCR]

go post on hybrid Z's forum boards. while its not a hybrid those guys know everything about Zs and could help you out. Rust is a major problem with those older z cars...not good. Anyways i know fo sho that hybrids forums are active as hell.

[FatMans240]

The clunking in the rear end of a 280Z or ZX on hard accelleration is caused by a kinda crappy setup with the differential. The front of the diff is real long, and to keep it from popping up when you get on it, they put these straps across the front of the diff...they're rubber and they wear out. They do make a solid mount for them, very easy to install and cost about $100... but it makes for a kind of noisy ride...Definitely better than that clunking bull****. It gets LOUD. Totalled my 78' before I had a chance to change mine. Hope I Helped ya out....

Tod

[SWSpiers]

The FATMAN240 had it right but only for the 70-78 Z car. They use a crappy rubber mount that likes to break. However, in 79 Nissan changed to a trailing arm rear suspension that doesn't use the same mount. I'd still check to see if the bolts are tight at the nose of the diff, and rear attachment, and while under there rotate the drive shaft for play at the rear joint. ZXs might have permanent u-joints, so that would be a driveshaft shop repair (sometime in there Nissan went from replaceable joints to permanent ones).

Also check the rear subframe mounts.