260z u-joint question/ bad tranny noise.

[2sixTZombii]

I haven't been on any Z forums lately, because for the most part google has not failed me much lately. a couple weeks ago I noticed a metallic noise when going into gear, my brother thought it was a u joint, and did sound about right so I googled it and searched a few forums and kept seeing stuff about the 280 u joints not being intended to be replaced and needing to press them out, use some other method to remove them. Then found threads where talked about replacing their 240z u joints like it was just a normal u joint job and found a write up on biopatient where he just pulled the c clips and drove it apart, then installed the new ones. this would lead me to beleive that the 280 and 240 u joints are different, now heres the issue, I have an early 260z So I'm not sure that leaves me, ore what the situation is. and while taking a friend to a to a doctors apointment today it started making all sorts of bad noise back there when taking off, and a weird metallic slapping while deaccelerating, I think its totally toast and I'm almost sure its a u joint now.

Tranny Noise

Now for the noise from the tranny. when shifting from 1-2 it makes a kind of nasty chirp noise that gets worse the higher RPM I'm at. and shifting to third it only makes the noise at high RPM shifts but it makes it again when going to fourth. and worst when shifting to reverse. now heres the thing sometimes when I haven't driven for several hours and its a cooler day it makes no noise no matter the RPM and shifts feel perfect, until I've been driving for about 20 minutes and then its back to making the noise. So when the tranny is at its coolest it feels great, but when its warm it makes a bad noise. I wondered if maybe when its warmed up the trans oil thins out to the point where it can't properly lubricate? I also thought maybe my clutch is getting weak. changing the gear would be good idea either way, but if I need to drop the trans to do the clutch It might be better to wait till thats done to do the gear oil. for the record the shifter bushings are brand new brass items.

Edited September 15, 2014 by 2sixTZombii

[EuroDat]

You should have the replacable type in the early model 260Z. It is easy to check by checking for circlips on the inside of the yoke flange. The "280Z" model had indents on the outside to hold the caps in place. The caps are also smaller in diameter than the 240Z type.

Spider cap diameter: 240Z to 260Z nov 74 are 25mm. 280Z 22mm and non servicable.

Does the tranny noise reduce or change when you put pressure on the gear shift? You mentioned brass bushings in the selector. A lot of people like changing the plastic bushes for brass, but if they wear they can rattle. Its almost unbelievable how much noise can be generated from two metalic components chattering.

Its could be possable after the tranny warms up and the oil thins, transfering your uni-joint vibration through to the selector. I think it was Grannyknot that had a similar rattle noise caused by the gear knob. Something to check.

Chas

[2sixTZombii]

the brass bushing were installed last week so there very new yet. it makes no noise once in gear, only on shifting. I checked the u joints and there worn but not enough to warrant real concern. I actually noticed I had a low tire which I think was what caused some of what I heard today. but I'm starting to think I need a new clutch, ugh don't wanna drop my tranny.

[beermanpete]

Perhaps a problem with the throwout bearing or pilot bearing?

[EuroDat]

If its a throw out bearing or pilot bearing problem, you could test it by warming up the engine with it in gear and the clutch disengaged. That will heat the two bearings without heating the transmission. Shouldn't take more than a couple of minutes. Then take it for a drive while the tranny is still cold.

While your under the bonnet, climb under and pull back the rubber boot on the clutch fork back. It helps the noise escape and you can hear the bearings a little better. Its a dust cover, but it also does a good job muffling the sounds in there.

Could also be the clutch plate torsion springs, but seems unlikly they would wear out before the clutch starts slipping.

Chas

[2sixTZombii]

Alright, last night, got a wild hair at about 10:00 and decided to try adjusting my clutch pedal, I didn't have very high hopes but figured I'd try something simple(and free) before gashing my wallet open to bleed money all over my car again. The first thing we fixed on this beast was the clutch master, in a dark cramped dirt floor garage. And I guess I hadn't really thought about it but we likely did a crappy job of adjusting then considering the circumstances. Started it up, pushed the clutch all the way in, and ran the shifter through all the gears. Before it felt like my shifter was connected to an 80 pound weight, and reverse was a total mess to shift into. Now it felt like it was connected to a stick of butter, and no gear including reverse made any noise. I took for a spin and felt worlds better, much much less shifting noise, and no stiffness or fight from the gear lever on shifting like before. It makes a slight chirp into second and fourth but it's mild now, and only when moving. I think maybe the fourth and second sychros are weak(possibly from inproper clutch release). I am hoping that fresh trans oil will cure this.

[2sixTZombii]

I at first was just gonna get valvoline or whatever gear oil in the trans as I plan to swap in a 5 speed later down the line anyway. But valvoline was nearly 16 bucks a quart, and there's no point redoing it if I just buy crap anyway. I can order redline in for about 15 bucks a quart. Which everyone says is great. But I also read that pennzoil sychromesh is great for problems like mine. Than also read it may eat the trannys insides overtime?!? Sycromesh can be had cheap locally so if that will work well, great but if it eats my trans than I'll go with the redline.

[EuroDat]

Before it felt like my shifter was connected to an 80 pound weight, and reverse was a total mess to shift into.

That sentence might have been handy in the first post. Hard the get into reverse is a sign the clutch disc it not disengaging properly.

Most common cause is the clutch hydraulic system or its adjustments. There are other problems like siezed spigot bearing, cracked clutch fork or dry/binding clutch disc splines not allowing the clutch disc to move away from the flywheel.

Anyway good to see you found a simple fix with the clutch hydraulics. Maybe fresh oil and replacing the worn uni-joints will be all it needs.

All the good quality oils that are suitable for our brass type synchros will generally cost more than oil for a modern style tranny. Im using red line fwiw.

Chas

[2sixTZombii]

I read the write up on alantic Z for doing the trans oil. He says he ordered two quarts but also said the tranny takes 2.5 which confused me. It if takes 2.5 wouldn't I need to buy three quarts? Also actually just finally realized that Blue is the guy in almost all the alantic z car tech tips. I am surprised it took me so long considering the car in his sig pic is the car in the tech tips. I have used that page as a guide for so many things on my z it's truly crazy.

[Captain Obvious]

I have used that page as a guide for so many things on my z it's truly crazy.

I'm with ya! I've lost count of the number of times now that I've studied the heck out of something and taken lots of pics... Only to find out later that I just reinvented the wheel and Blue already has the same analysis on his site from years ago!

[EuroDat]

Same here, if that website was a paperback, I would have worn it out by now and be looking for a new one. Priceless.

Hats off to Blue for all the effort.

Chas

[2sixTZombii]

I never updated this but a shortly after starting this thread I called around to all the parts stores and as it turned out the local independent parts store had the best price for moog and could get them in the next day. I pulled the drive shift replaced the u joints and got back in, easy job actually, only bad part was I filleted my arm and caused a leak at the glass pack, but it's just as well, my arms about healed and I needed to replace that glass pack anyway. Car is 100% nicer to drive, still a noise on second, but It's not a huge deal. I want to swap to a five speed in the near future anyway.