!Need help! T56
 

Aright I'm gonna try my best to explain what's going on.

First Ill start with some background. '97 LT1 6-speed. Purchased the car with 64k on the clock. I'm the second owner, so I couldn't tell you if the clutch had be replaced or not, so mystery clutch/mystery miles on it. Never actually roasted clutch, although I did love tap a gear twice. Think that covers it.

So brought the car to college for the last month, a 6.5hr/410 mile trip. This would be the longest trip Ive ever taken it on. It ran great, cruised 70ish out here, did hit some traffic, did not ride the clutch very much. Up until then everything was fine, shifted smooth, no vibrations or other noises. I get off 79 to do a bit of back road driving and I noticed that when I went to put it in 5th (around 40mph so 15-1600 rpm), clutch pedal to the floor, I could feel what I think was grinding? but not nearly as loud like when you miss a shift. First I figured it was a fluke.

Well went back to neutral, then put it back into gear, and same thing happened in 5th, although it didn't happen every time. Also, nothing out the ordinary when I shift back to neutral (no grinding, doesn't jump out of gear).

First thought was a bad syncros in 5th, but I did note that it did it to me when I down-shifted into 2nd (around 20mph, rpm match). I made it to school let it cool down for a few hours thinking maybe it was running hot (70mph 6hrs you know). Was making a left, car was in 2nd, turned saw some kids so I nearly had to stop, low enough for 1st but as I put it in first I also got that grinding feel/noise

Basically to sum it up, car made a grinding noise/feel (pedal and shifter) after a long road trip. Does not happen consistently, every once and a while. Also note that it doesn't happen in every gear, nor is it consistent (doesn't happen more or less by consecutively going through gears or picking at random)




Open to questions so ask away!

I'm not gona use it much because I don't want to worsen whatever it is :-x

Could be the throw out bearing or just clutch chatter? With the car in Neutral does the grinding start/stop when you push in or left out the clutch?

How is the fluid level in the trans? I'd suggest changing the trans fluid.

I've had good luck using Redline, allot of people like Royal purple as well. FYI, the T56 uses automatic trans fluid = stock Dexron III. So either Redline D4 AFT or Royal Purple MAX ATF is the right upgrade.

You'll need 4 quarts

So I took it out for a bit of a run, gave it a full 24hrs to cool down and sit. Drove it for about 40 mins, with some stop and go as well as a little bit of highway to get some speed. I did NOT notice anything this time. Shifted smooth, no noise, no grinding feel or anything like that.

To answer your ?s, honestly clutch doesn't make any noise really, would clutch chatter just start randomly? Also it seemed as though if I played with the clutch the noise/grinding went away. If it was in neutral or any gear, the noise/grinding stopped

Checked the hydraulic fluid seemed to be a bit over half (read somewhere it should be about 2/3s full). Fluid looked normal, no real discoloration.

I had my dad talk to my mechanic (since he knows the car pretty well) and he also suggested changing the fluid, so if everything is well, when I get back thats what I'm doing.



Could this thing have happened from gettin' hot? I mean 7hrs worth is a lot of driving... maybe she was just too hot? I'll keep my eye on it though

Probably, I'd guess the throwout bearing was making the noise. Still a good idea to change fluid in the trans. 64K on the clutch on the clutch isn't really that much but that also depends on how the car was driven. I replaced my stock clutch at 36K because the chatter was driving me nuts! Still held find, but had to keep explaining the noise to people every time I gave some a ride!

Grinding sucks, but if its only occassional, then I wouldn't worry too much about it. Now if it was happening a lot then I'd be more concerned. Is it the stock shifter? If its aftermarket, maybe you can just adjust the stops...

I'll trade ya my good ol' 4l60e for it Josh!

The fluid hasn't been changed in 45k miles, has no torque management, car makes within 5rwtq of the transmissions max rating, I autox it, manually shift it on occasion (for gear holding purposes, not drag), and it has 106k miles on it. It doesn't grind or slip though, ever, and the fluid is still nice and pink :nod:

In neutral I can slightly hear the TOB when stopped with my head under the car :lol: Oh I failed to mention it currently has 78,9xx miles on it if that makes a difference

Nope, stock shifter... needs a short throw though haha

Keith, I'd never go to auto in a car like this! It's far too much fun and sounds wayy better :wink: But your trans is def not bad for the amount of abuse I've seen you give it haha but you need to slap a manual in there !

hopefully by next summer it'll be a 6 speed. the auto works surprisingly well for autox and it's alright for daily driving but if i start doing track days i think the heat will kill it.

UPDATE:


So i had the trans flushed and filled with fresh fluid. Mechanic said it was brown, probably has never been changed before. Said the magnet was pretty much clean, so at least that was good news.

However i just took it round town quick, not enough to heat up the trans. I noticed that slight grind again. Happened when i pushed the clutch in and put it in 2nd after shifting from 2,500rpms and 3rd. Although i tried again and if i let the clutch up slower it acted normal...

Any other ideas?

maybe i got an air bubble in the clutch line?

I saw you driving around at 8:15ish haha

more info, hopefully this isnt too confusing lol but i took my dad along to show him make sure i wasnt hearing/feeling things. and i had my foot to the floor with the clutch, coasting about 25mph ish at idle and i put it in and out of 3rd a few times and it started to almost grind. more of when you release the clutch too early and bang off a gear.. anybody following here?

this doesnt always happen everytime i shift, but could this be a bad TOB ? or other bearing?

man I hate to say it...but it seems like it may possibly be your opti spark going bad. Very common in the LT1 cars.

ok ok ok...on a serious note, very strange what you are describing. Have you taken it to a trans shop and asked them their opinion?

My mechanic thinks i could be the synchro beginning to wear out.. im going to a trans shop on monday see what they can do for me

anything i should know so i dont get ripped? is it necessary/a good idea to replace everything while its out?

Lucas transmission fluid FTW!!

Have you bled your clutch master cylinder? I would do that just to do it and go from there since you already drained the fluid in the trans and put fresh stuff in it.

I say that sounds like a pilot bearing getting mashed up..That happened to me only found out when I pulled my tranny to get rebuilt.