Freshly rebuilt T56, 1st gear clacking and input shaft noises
02-25-2013, 05:15 PM
#1
Freshly rebuilt T56, 1st gear clacking and input shaft noises I finished a turbo LS1 swap on a '92 240sx recently, and the t56 is making a couple of interesting noises. You can hear the first gear noise in this video, at 0:20, and again at 1:20.
Another noise has been getting louder over the past couple days, it is not the pilot bearing or the throwout bearing because it is gear dependent and motor independent. It pretty much has to be the input shaft or the mainshaft because it happens in every gear, even with the clutch pushed in and rolling, and it stops making noise when the car stops moving, even with the engine running.
This transmission was rebuilt by some company (not sure who) before it was sold to me last year, so I'm thinking they did something wrong. Trans only has about 200 miles on it, and it was making the 1st gear noise ever since we got the car running. Do you think this transmission is fubar and needs another rebuild or are these noises normal for breaking in a t56?
Another noise has been getting louder over the past couple days, it is not the pilot bearing or the throwout bearing because it is gear dependent and motor independent. It pretty much has to be the input shaft or the mainshaft because it happens in every gear, even with the clutch pushed in and rolling, and it stops making noise when the car stops moving, even with the engine running.
This transmission was rebuilt by some company (not sure who) before it was sold to me last year, so I'm thinking they did something wrong. Trans only has about 200 miles on it, and it was making the 1st gear noise ever since we got the car running. Do you think this transmission is fubar and needs another rebuild or are these noises normal for breaking in a t56?
03-06-2013, 08:48 AM
#3
It's a custom steel driveshaft, car is using Daft Innovations mounts. Driveshaft yoke had plenty of movement in and out of the tailshaft so I don't think that's the problem. Also, it only makes that clacking sound in 1st gear. If I start in 2nd, it doesn't do it.
03-10-2013, 07:07 PM
#4
So I found the source of the noise. Whoever "rebuilt" this transmission did about the shittiest job I've ever seen. Check out the "shim" they created with some tin snips.
So I'm on the tick website ordering a shim kit and a new input shaft bearing, do you guys think it would be wise to upgrade a few other things? I'm thinking a steel 3-4 fork, billet keys, and bronze pads. Is there anything that's absolutely necessary for 5-600 whp (not drag launching)?
So I'm on the tick website ordering a shim kit and a new input shaft bearing, do you guys think it would be wise to upgrade a few other things? I'm thinking a steel 3-4 fork, billet keys, and bronze pads. Is there anything that's absolutely necessary for 5-600 whp (not drag launching)?
03-12-2013, 11:33 AM
#6
Ugh, so I'm going through the rest of the transmission and found some more stuff wrong with it.
The 5/6 gear has a broken tooth and had a cracked one. I tapped the cracked one with a drift to see if it was just the corner or more and a fairly large chunk came off. Do you guys think I can still run this gear or do you think I should buy another one? They aren't cheap... $180. I'm not sure if the broken part of the tooth even contacts the other gear, that's why I'm asking.
The bearing on the end of the countershaft is destroyed.
I found out who sold the transmission to the guy I bought it from. He is a user on this forum, blacknite.
The 5/6 gear has a broken tooth and had a cracked one. I tapped the cracked one with a drift to see if it was just the corner or more and a fairly large chunk came off. Do you guys think I can still run this gear or do you think I should buy another one? They aren't cheap... $180. I'm not sure if the broken part of the tooth even contacts the other gear, that's why I'm asking.
The bearing on the end of the countershaft is destroyed.
I found out who sold the transmission to the guy I bought it from. He is a user on this forum, blacknite.
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03-13-2013, 11:35 AM
#8
So you're saying I could take a diamond grinding wheel, shave the sharp edges round and smooth and you wouldn't worry about it? I guess that's better than throwing $180 on a gear, especially 5th which I wouldn't use much anyway.
The puller is a harbor freight bearing puller with a 2 of the jaws from their 8" 3 jaw puller clamped in it. Every other guy I've seen uses a bunch of the jaws taped together, this was an easier and better option to pull that gear IMO.
The puller is a harbor freight bearing puller with a 2 of the jaws from their 8" 3 jaw puller clamped in it. Every other guy I've seen uses a bunch of the jaws taped together, this was an easier and better option to pull that gear IMO.
03-13-2013, 03:51 PM
#9
Yep. I use a little dremel tool with a cone shape grinding stone. Service manual even shows small corner chips like that as "repairable" instead of "replace". I have a buddy that chipped 2 teeth almost exactly like you have while he was pulling the 5/6 cluster. I cleaned them up and it's been running in his car for 5 years in a 450hp 3rd gen. No noises, no problems.
03-14-2013, 07:40 AM
#10
I just read the OP and was going to suggest that the shimms were off. It was a pain to get it just right with mine.
As for the 5/6 driven gear. What do the splines on it and the main shaft look like? Is there any wear? I had to replace my main shaft and 5/6 driven because the main shaft is just a tad too small and will wear over time. It's about .003" too narrow. Just make sure you take your time with the shimming.
If you have to replace bearing (which it looks like you do) go about .002" tighter on the shimming. If they are used stick to what the t-56 manual says. I used about .001-.003" preload on the three places on mine but my bearings were "broken in" already. The .001"-.003" also helps compensate for the little bit of silicone in the seams once you finally button her up.
As for the 5/6 driven gear. What do the splines on it and the main shaft look like? Is there any wear? I had to replace my main shaft and 5/6 driven because the main shaft is just a tad too small and will wear over time. It's about .003" too narrow. Just make sure you take your time with the shimming.
If you have to replace bearing (which it looks like you do) go about .002" tighter on the shimming. If they are used stick to what the t-56 manual says. I used about .001-.003" preload on the three places on mine but my bearings were "broken in" already. The .001"-.003" also helps compensate for the little bit of silicone in the seams once you finally button her up.
03-21-2013, 12:28 AM
#11
I just read the OP and was going to suggest that the shimms were off. It was a pain to get it just right with mine.
As for the 5/6 driven gear. What do the splines on it and the main shaft look like? Is there any wear? I had to replace my main shaft and 5/6 driven because the main shaft is just a tad too small and will wear over time. It's about .003" too narrow. Just make sure you take your time with the shimming.
If you have to replace bearing (which it looks like you do) go about .002" tighter on the shimming. If they are used stick to what the t-56 manual says. I used about .001-.003" preload on the three places on mine but my bearings were "broken in" already. The .001"-.003" also helps compensate for the little bit of silicone in the seams once you finally button her up.
As for the 5/6 driven gear. What do the splines on it and the main shaft look like? Is there any wear? I had to replace my main shaft and 5/6 driven because the main shaft is just a tad too small and will wear over time. It's about .003" too narrow. Just make sure you take your time with the shimming.
If you have to replace bearing (which it looks like you do) go about .002" tighter on the shimming. If they are used stick to what the t-56 manual says. I used about .001-.003" preload on the three places on mine but my bearings were "broken in" already. The .001"-.003" also helps compensate for the little bit of silicone in the seams once you finally button her up.
I ended up finding another thing in the transmission when doing the rebuild that makes me think it was the true cause of the problem. I dunno how you let a needle bearing roller fall behind a shim and not notice it when putting everything back together...
I ended up preloading the countershaft extension and countershaft a bit but left the factory amount of play in the input shaft.
Last edited by killernoodle; 03-21-2013 at 12:36 AM.
