80LS1T Posted September 18, 2005 Share Posted September 18, 2005 Well I was going to do some engine tuning today but I think I have some issues with my tranny(T56). When I put it in gear and release the clutch there is some grinding right as the car starts to move. There is also a knocking noise when the clutch is not pushed in. I had that same noise when I had the centerforce dual friction clutch in there. I also have a very harsh vibration when I rev the engine up. The flywheel and clutch are new. Its a Fidanze alluminum flywheel with a SPEC stage 3 clutch. The clutch and flywheel were balanced before the install. However I couldnt put the small washer on one of the bolts(it was used to make it balanced) for the flywheel to pressure plate because the bolt was too short. I ended up stripping the hole on the flywheel and having to helicoil the hole. I didnt put that washer on that bolt head because the bolt was obviously too short. Do you think that missing washer would cause a really bad vibration? I could see some but this vibration that I have is really bad. Also would it be possible that the flywheel isnt balanced for my engines rotating assembly? When I rebuilt the engine the whole rotating assembly was balanced together, including the flywheel. Is it possible that the new flywheel is throwing it out of balance? I have a really bad feeling that the tranny will be coming back out! I thought all that noise that I had previously was just clutch chatter but as it turns out that wasnt all of it I guess! I know some of it was because the flywheel had about a billion hotspots on it. This was probably due to an improper break in, aka too many burn outs. If I do pull the tranny back out it will get rebuilt. It has about 100,000 miles on it so its probably due. Right now Im think it needs some bearings internally, like an input shaft bearing. If I do rebuild though it will get all new bearings and syncrows. Damn just when I thought I had all the bugs worked out! This tranny noise is really bitting me in the ***! Any ideas what is causing the grinding noise? or vibration? or noise? LOL Anyone ever rebuild one of these? What did it cost for parts? Guy Quote Link to comment Share on other sites More sharing options...
Guest FasterbyFosta Posted September 20, 2005 Share Posted September 20, 2005 Well I was going to do some engine tuning today but I think I have some issues with my tranny(T56). When I put it in gear and release the clutch there is some grinding right as the car starts to move. There is also a knocking noise when the clutch is not pushed in. I had that same noise when I had the centerforce dual friction clutch in there. I also have a very harsh vibration when I rev the engine up. The flywheel and clutch are new. Its a Fidanze alluminum flywheel with a SPEC stage 3 clutch. The clutch and flywheel were balanced before the install. However I couldnt put the small washer on one of the bolts(it was used to make it balanced) for the flywheel to pressure plate because the bolt was too short. I ended up stripping the hole on the flywheel and having to helicoil the hole. I didnt put that washer on that bolt head because the bolt was obviously too short. Do you think that missing washer would cause a really bad vibration? I could see some but this vibration that I have is really bad. Also would it be possible that the flywheel isnt balanced for my engines rotating assembly? When I rebuilt the engine the whole rotating assembly was balanced together' date=' including the flywheel. Is it possible that the new flywheel is throwing it out of balance? I have a really bad feeling that the tranny will be coming back out! I thought all that noise that I had previously was just clutch chatter but as it turns out that wasnt all of it I guess! I know some of it was because the flywheel had about a billion hotspots on it. This was probably due to an improper break in, aka too many burn outs. If I do pull the tranny back out it will get rebuilt. It has about 100,000 miles on it so its probably due. Right now Im think it needs some bearings internally, like an input shaft bearing. If I do rebuild though it will get all new bearings and syncrows. Damn just when I thought I had all the bugs worked out! This tranny noise is really bitting me in the ***! Any ideas what is causing the grinding noise? or vibration? or noise? LOL Anyone ever rebuild one of these? What did it cost for parts? Guy[/quote'] From your name and info, Im assuming you have a lt1. Is the motor stroked, or built up? A lot of times people will internally balance a rebuilt LT1, but that means you have to balance the flywheel accordingly. The stock lt1 flywheel/flexplate is weighted for balancing. If that weight was removed for the new motor setup, you will have a bunch of vibration/noise issues. I had a similar problem with my 396 lt1, since the previous owner didnt tell me that the flywheel was balanced to neutral, instead of weighted, and I changed it out for a weighted one, and suddenly had very similar problems to the one you are, so I re-balanced the new one to neutral, and had no more issues. Quote Link to comment Share on other sites More sharing options...
Jeff Posted September 20, 2005 Share Posted September 20, 2005 Sounds like a flywheel balance issue to me as well. I'm running a Spec aluminum flywheel in my LT1 powered Trans Am and the stock bolts were too short since the aluminum flywheel has a thicker flange. I picked up new bolts and washers from a local machine shop so you may want to do that while you have it apart. I haven't rebuilt a T56 but there is a good write up here. Quote Link to comment Share on other sites More sharing options...
80LS1T Posted September 20, 2005 Author Share Posted September 20, 2005 Yeah Im thinking the vibration issues is deffinetly the new flywheel. The engine was internally balanced. I am going to pull the tranny this weekend rather than start on the body work. I was really excited about starting my first body work but it will have to wait now. As for the knocking, still not sure what that is. Im going to have one of the guys I work with have a look at it and see what he thinks. We'll see where I go from there. Guy Quote Link to comment Share on other sites More sharing options...
Danno74Z Posted September 21, 2005 Share Posted September 21, 2005 80LT1 Here are a couple of emails I kept from Centerforce on this very subject. Dear Danno, Our sources and expertise have confirmed that the LT1 engine is an externally balanced engine. With that said, a replacement flywheel, ours or another, would have to have the factory counterbalance specification in order for the flywheel to be a bolt on part. The 700170 is a flywheel with a counterbalance which offsets or counteracts the engine's internal out-of-balance condition. A ZZ4 crate engine is also an externally balanced engine. The reference to having your LT1s internal rotating assembly balanced and thus needed a zero or neutral balanced flywheel was to provide awareness to you that if you did have or planned on having your LT1s internal rotating assembly zero balanced, our 700170 and 700160 would NOT be appropriate. Our 700170 and 700160 flywheels are designed as direct bolt in replacements for factory (OE) original equipment engines with factory balance specifications. Also, if you are using an aftermarket crankshaft, you may have to obtain a zero balanced flywheel depending on the balance characteristics of the crankshaft itself. If you have any more questions or need any more clarification, please feel free to give us a call. Thanks! Rick Mard Technical Representative Centerforce Clutches, A Div. of Midway Ind. 928/771-8422 x36 Dear Danno, Thank you for submitting your technical question with us. Unless you are having your LT1s rotating assembly rebalance, a counterbalanced flywheel with the OE (original equipment) specification will be necessary. The following combinations of flywheels and clutch assemblies should work: 153 Tooth w/ 10.5" Clutch 700170 Steel billet 153 tooth flywheel DF161675 10.5" Dual-Friction clutch w/ 26-spline 1-1/8" input shaft 168 Tooth w/ 11" Clutch 700160 Steel billet 168 tooth flywheel DF148552 11" Dual-Friction clutch w/ 26-spline 1-1/8" input shaft The flywheels are both .950" thick, measured from the friction surface to the crank flange surface. If you have any more questions we suggest calling us directly and speak with one of our technical representatives. Thanks for considering Centerforce! Quote Link to comment Share on other sites More sharing options...
80LS1T Posted September 21, 2005 Author Share Posted September 21, 2005 Well Im pulling the tranny this weekend. I am going to run the engine with the flywheel bolted on and then with it off. I will know for sure if thats the issue then. I am pretty sure it is. Then Im going to have it balanced at the machine shop that I had the rest of the rotating assembly balanced at. The guy I bought it from said it was balanced but if it was balanced to the OEM specs that would explain why its not balanced for my rotating assembly, since mine is internally balanced. I wish I would have thought of this when the tranny and engine were out. Its a lot easier to install the engine and tranny together rather than pulling the tranny by itself. Oh well live and learn I guess. I know I will never do this again! LOL Then I have to figure out what to do about the knocking from the tranny and the grinding noise. But I will handle it one step at a time! Guy Quote Link to comment Share on other sites More sharing options...
80LS1T Posted September 27, 2005 Author Share Posted September 27, 2005 Well I have the tranny out and it will be getting torn down probably late next week. A guy that I work with will be doing to rebuild for me. I cant wait to find out whats wrong with the bastard! LOL I just want it fixed! So anybody know where to get parts for these things? And as for upgrades? I know its rated for 400ft-lbs but is there anything that is the weak link in these beasts? I have found rebuild kits for them for about $250-300 for all the bearings and syncros. I hope that i dont need any shafts for it because they sure are expensive! Guy Quote Link to comment Share on other sites More sharing options...
Mike kZ Posted September 27, 2005 Share Posted September 27, 2005 I hope that i dont need any shafts for it because they sure are expensive! Guy Your telling me! I had to replace the 5,6 shaft, and one of the shift forks in my T56.The 5,6 rail was bent, and the shift fork was broken in two. It cost me $800! That was in 2001. Quote Link to comment Share on other sites More sharing options...
jbc3 Posted September 27, 2005 Share Posted September 27, 2005 Let me know if you need any of the T-56 tranny parts. I have many/most of the spare parts in the garage. Jody Quote Link to comment Share on other sites More sharing options...
80LS1T Posted September 27, 2005 Author Share Posted September 27, 2005 Let me know if you need any of the T-56 tranny parts. I have many/most of the spare parts in the garage. Jody Ok sounds good! Mike what was your tranny doing when you had to fix it? Guy Quote Link to comment Share on other sites More sharing options...
80LS1T Posted September 27, 2005 Author Share Posted September 27, 2005 Just got back from the machine shop. Bad news for me. Turns out that I wont be able to use my alluminum flywheel because they cant balance it unless they have the crankshaft. Since my old flywheel was not neutrally balanced neither is my engine. The post 86' engines use counter weights that offset the counter weights on the flywheel. If my engine was out on the stand I could just pull the crankshaft out and bring it in but Im not going to pull the motor when I could just sell this flywheel and get one that has counter weights on it. Well one problem has been solved atleast! Guy Quote Link to comment Share on other sites More sharing options...
Mike kZ Posted September 28, 2005 Share Posted September 28, 2005 Mike what was your tranny doing when you had to fix it? Guy I backed out of the garage, on to the street, put it in 1st, let the clutch out, and the car stalled like the brakes where on. I tried all other gears, and neutral, same thing. I had to push the clutch in to move it. I guess 5th or 6th gear was in, but the shifter didn't do anything. 5,6 rail must of bent when the car my tranny came from wrecked. Quote Link to comment Share on other sites More sharing options...
Mikelly Posted September 28, 2005 Share Posted September 28, 2005 D&D performance is my recommendation for parts for your T56... They have everything to beef it up, including the forged strut pins and 3/4 shift fork, as well as the Kevlar Syncros from C5 supplied T56s... Prices aren't that bad considering... Mike Quote Link to comment Share on other sites More sharing options...
Danno74Z Posted September 29, 2005 Share Posted September 29, 2005 80LT1, McLeod Industries makes both an aluminum and steel flywheel for the LT1 with counterbalance weights. http://www.mcleodind.com/cgi-bin/fccgi.exe?w3exec=w3ezmenudriver&menuvalue=38&currmenuid=WMM&src1=/catalog_htm/2003cat.htm&w3hostname=MCLEOD If the link does not work go to page 18 in the cat. Danno74Z Quote Link to comment Share on other sites More sharing options...
80LS1T Posted September 29, 2005 Author Share Posted September 29, 2005 Well my machinist suggested going back to the stock flywheel because thats what my crankshaft was balanced with. I didnt really want an aluminum flywheel, it just came with the clutch when I bought it off of ebay. I just figured I'd try it and see if I liked it. I am selling the Fidanza flywheel on ebay and them Im going to buy a new stock one from GM. Thanks for the info though. Guy Quote Link to comment Share on other sites More sharing options...
zeeboost Posted October 13, 2005 Share Posted October 13, 2005 I don't know if that balanced flywheel was even your problem in the first place (although I'm sure it didn't help). I'm having similar problems like you, but I have pre-86 350. I even have the Spec Stage III clutch to boot (actually, I think you were the one that recommended it to me ) Anyways, here's my problem. If I start the car in neutral and then try to put it in gear, it won't go in. However, if I start the car in gear with the clutch in, it will begin to surge forward and I hear some metal to metal clanking and grinding noises, but after a couple of seconds it will go away and I can drive the car like normal. However, as soon as I turn the car off, I'll have to do it all over again. IT'S FREAKIN FRUSTRATING!!! Usually right after that happens and when I drive in 1st gear, it will shake horribly, like you're describing. But as soon as shift out of it, it will feel normal. I'm going to replace the slave cylinder within the next hour with the factory T-56 slave from GM (I was using an O'Reilly slave before, so I'm just ruling out a faulty slave) It's weird, because I never had this problem before with the Centerforce dual friction clutch, but then when I switched over to the Spec Stage III, after about a thousand miles (mostly highway, and VERY light driving) it started doing this. I just got in the car one day, after it had been sitting for about a week, and it did this. I talked to the transmission mechanic at work, and he's never heard of any problem like that. He told me I was doing the right thing by ruling out hydraulics. I'm wondering if this could be a problem with the clutch. I've yet to pull the tranny back out, but it seems inevitable. Did you find anything else wrong with yours, or notice any kind of scratches or scores on any of the contact points? Looks like we'll be going at this together. Quote Link to comment Share on other sites More sharing options...
80LS1T Posted October 13, 2005 Author Share Posted October 13, 2005 Oh trust me mine vibration was a balance issue, my machinist assured me of that. He knew right away when I told him what I had going on. I just sold that flywheel and I am going back to the counter balanced factory flywheel. As for your problem, sounds more like either internal tranny problems or yeah possibly a clutch/throw out bearing? Not too sure. I havent got my tranny ripped down yet. I know that once it is I will find out what that figgin knocking noise that I have been chasing since day one is though! Guy Quote Link to comment Share on other sites More sharing options...
zeeboost Posted October 13, 2005 Share Posted October 13, 2005 Hmm...well, it's 1:00 a.m. over here, and I just installed the new slave cylinder. I bench bled the m/c, connected the slave, installed it on the Zx, and then had my g/f pump the pedal while I bled it out. Interestingly, I started the car in neutral, pumped the clutch pedal three times, and slid it into first...the only thing different was that the front of the car was jacked up. As soon as I dropped it back down and took it out, I could tell that the system still needed to be bled out a little more. I would bleed it again, but like I said earlier, it's late enough. But, this at least gives me a new hope. Have you thought about your hydraulics being the culprit to the knocking / grinding noise? Does it have trouble going into gear, or is it just when you're letting out on the pedal? Quote Link to comment Share on other sites More sharing options...
Nissan-Fan Posted October 13, 2005 Share Posted October 13, 2005 sorry if this is sort of off topic, but i dont think its right to start another thread. Me and a friend are starting another project car, a 1978 Datsun 280z. Our plan is to put in a rebuild 350SBC, and use the Jags that run mounts and headers. We want to use a T56 tranny from a wrecking yard, but i would like to know if there would be any issues with the tranny and those mounts fitting correctly. Also, can anyone reccomend what i should be using for a diff? is the stock r200 enough to support a mild carbed 350 with a 6spd? thanks, and once again, sorry for the highjack. Quote Link to comment Share on other sites More sharing options...
Mike kZ Posted October 13, 2005 Share Posted October 13, 2005 sorry if this is sort of off topic' date=' but i dont think its right to start another thread. Me and a friend are starting another project car, a 1978 Datsun 280z. Our plan is to put in a rebuild 350SBC, and use the Jags that run mounts and headers. We want to use a T56 tranny from a wrecking yard, but i would like to know if there would be any issues with the tranny and those mounts fitting correctly. Also, can anyone reccomend what i should be using for a diff? is the stock r200 enough to support a mild carbed 350 with a 6spd? thanks, and once again, sorry for the highjack.[/quote'] no issues, and yes Quote Link to comment Share on other sites More sharing options...
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