Rear end banging and wheel hop
10-20-2014, 11:49 PM
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Rear end banging and wheel hop Ok so here is what's going on. I have an 01 trans am that had 2.73's, slp lid, borla adj catback, bmr lowering springs, koni str.t struts/shocks, and umi lca relocation brackets. I just got a tsp 233/239 112 lsa cam, dual spring kit with titanium retainers, chromemoly pushrods, katech c5r timing, ls7 lifters, tsp stainless 1 7/8" headers, tsp ory, yank ss3600 stall, bmr 70266 trans cooler, and a tune.
After I got the car back all was fine, I couldn't really hook with kdw2 with 99% tread, but all was well. About a week later I started feeling a slap when it shifted from 1st to 2nd. Then progressed alot more to where it sometimes slaps a few times on a light roll from a dig, or a 20-30 roll. First thing I thought was I broke my transmission mount. Had a buddy ride with me and he thought it was the torque arm mount. So we put it on jackstands and checked the transmission mount and all was good. Pulled the torque arm bushing out and swapped it with his out of his ss mount and all. Took it for a drive and it seemed to mostly fix the initial problem of it slapping the bottom.
Now a new problem started, I have pretty bad wheel hop. I never had any issues with wheel hop before, and was running the lca relocation brackets in the top hole. It didn't start until after the initial slap feeling and sound we were hearing before. There is also a sound that is a loud banging noise coming from the rear end that you can also feel and you only hear it when the converter locks up. It will not do it under load when you give it gas, only if it is a steady speed, or you let off the gas. when the conveter isn't locked it doesn't make the sound at all.
So we jack the rear end up on stands and take it up to speed for lockup. All is good until it hits lockup, then it gets a horribly bad clanging and you can feel it sitting inside the car. Sounds like it is almost coming from above the axel. So we take the driveshaft out and both u joints were good. Then take the cover off the diff to check it out. There were no shavings/metal at all, we checked out the spiders gear and everything looked perfect. Then we pulled an axel off to make sure it wasn't a wheel bearing ( even though we had no whine) and they looked fine. It isn't the exhaust and we cannot think of anything else it could be. So I have two problems that has started a week after the upgrades, the wheel hop, and the clanging in the rear at lockup. Slapped everything back together and moved the lca relocation brackets to the 2nd hole and took it for a drive with no difference.
Questions:
1. Is there something in the transmission or anything that could cause that at lockup only. It will only do it at a steady speed or deceleration when locked. Under throttle or unlocked it will not do it.
2. What would cause the wheel hop now after it wasn't having any problems? Nothing has been changed to the car at all. I do have a set of factory ws6 coil springs and was wondering if I put those in rear if they would help my wheel hop by putting it back to factory height? I am also running in the second hole in the lca relocation brackets and wam going to try the bottom hole.
After I got the car back all was fine, I couldn't really hook with kdw2 with 99% tread, but all was well. About a week later I started feeling a slap when it shifted from 1st to 2nd. Then progressed alot more to where it sometimes slaps a few times on a light roll from a dig, or a 20-30 roll. First thing I thought was I broke my transmission mount. Had a buddy ride with me and he thought it was the torque arm mount. So we put it on jackstands and checked the transmission mount and all was good. Pulled the torque arm bushing out and swapped it with his out of his ss mount and all. Took it for a drive and it seemed to mostly fix the initial problem of it slapping the bottom.
Now a new problem started, I have pretty bad wheel hop. I never had any issues with wheel hop before, and was running the lca relocation brackets in the top hole. It didn't start until after the initial slap feeling and sound we were hearing before. There is also a sound that is a loud banging noise coming from the rear end that you can also feel and you only hear it when the converter locks up. It will not do it under load when you give it gas, only if it is a steady speed, or you let off the gas. when the conveter isn't locked it doesn't make the sound at all.
So we jack the rear end up on stands and take it up to speed for lockup. All is good until it hits lockup, then it gets a horribly bad clanging and you can feel it sitting inside the car. Sounds like it is almost coming from above the axel. So we take the driveshaft out and both u joints were good. Then take the cover off the diff to check it out. There were no shavings/metal at all, we checked out the spiders gear and everything looked perfect. Then we pulled an axel off to make sure it wasn't a wheel bearing ( even though we had no whine) and they looked fine. It isn't the exhaust and we cannot think of anything else it could be. So I have two problems that has started a week after the upgrades, the wheel hop, and the clanging in the rear at lockup. Slapped everything back together and moved the lca relocation brackets to the 2nd hole and took it for a drive with no difference.
Questions:
1. Is there something in the transmission or anything that could cause that at lockup only. It will only do it at a steady speed or deceleration when locked. Under throttle or unlocked it will not do it.
2. What would cause the wheel hop now after it wasn't having any problems? Nothing has been changed to the car at all. I do have a set of factory ws6 coil springs and was wondering if I put those in rear if they would help my wheel hop by putting it back to factory height? I am also running in the second hole in the lca relocation brackets and wam going to try the bottom hole.
10-21-2014, 05:59 PM
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Update: pulled the BMR springs out of the rear and put the stock ws6 ones on. Car sits almost 2" higher in the back but it got rid of the wheel hop. Traction seems a little worse now but at least my rear end is safe. Now I need to figure out why lockup is causing the clanging sound. I'm going to call yank tomorrow and see if they've ever heard of this problem. Tried them today but the number was busy for some reason. Anyone know a different #?, I called 775-826-9955. Open to all ideas so please don't hesitate to post.
10-21-2014, 06:48 PM
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If it only happens during lockup it could be the lockup clutch chattering trying to stay engaged?? Did you break it in properly? Is it tuned for 100% lockup engagement, cause the stock tune tries to slip the clutch.
10-21-2014, 07:17 PM
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Do you have adjustable lower control arms and an adjustable torque arm? You'll need adjustable lower control arms to use the lower holes in the lca brackets. The lower holes are usually where you'll find the chassis gets the best traction as you want the lower control arms to be horizontal to the ground. If you have the factory torque arm, check to see if it is starting to bend approx six inches ahead of the rear. The stock ones are made out of sheet metal and are prone to bending.
As 01ssreda4 mentioned, your tune may be why the lock up is causing you problems. Bob
As 01ssreda4 mentioned, your tune may be why the lock up is causing you problems. Bob
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10-21-2014, 08:47 PM
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Well I would probably say it was not broken in properly. The reason I say that is because it was all put in at the same time and then street tuned. I was worried about that myself. I guess if it is then the builder and tuner would probably say they broke it in correctly. I put about 150 miles on it before I tore into it good. They put about 35 miles on it so it's very possible.
10-21-2014, 08:54 PM
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The LCA and torque arms are stock so I'll check them out in the morning and see. I had to take my car back to them because ses light came on and threw code p0757 and they deleted it out. They also lowered my lockup a little by my request. Dave Steck (DSX) is who did the tuning and he's pretty reputable. Has his and the builders advertisements on the beginning of some of the txy2k14 videos. They also have quite a few cars on YouTube they have tuned. But I am still wondering if it is the tune or it wasn't broken in properly.
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10-21-2014, 11:37 PM
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Right now it's at 55, originally 60 is what they set it at "because of my 2.73's", but my buddy plugged his scan tool up Sunday and manually locked it at 45. It ran fine so I think I'm going to have it set there.
10-22-2014, 01:22 PM
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David,
The chattering noise you are hearing in the rear end is from the bucking from the camshaft cause by several things working against you with this setup (as I warned you initially). When you have a decent sized camshaft, you will get some bucking on deceleration at near idle RPM's...when you lock up the converter at lower speeds (per your request) along with a 2.73 gear, it is going to have some issues like this. At 55 mph, cruising at light throttle with 2.73's, the rpm's are just too low to for a full lockup, in my opinion.
Your converter is tuned for full lockup (zero slip) because I believe it would cause premature converter lockup clutch wear with the 2.73's when cruising and partially locked up.
Locking up the converter at 45 mph will make this issue worse on deceleration, but may feel fine with everything loaded on acceleration. We can set it to whatever you want, even though I wouldn't recommend it.
We go through a series of events to help break in a new converter, and also never lock up a new converter while tuning any wide open throttle. The converter isn't your issue/problem.
You need some gears man! Call me if you have any questions.
--Chad
The chattering noise you are hearing in the rear end is from the bucking from the camshaft cause by several things working against you with this setup (as I warned you initially). When you have a decent sized camshaft, you will get some bucking on deceleration at near idle RPM's...when you lock up the converter at lower speeds (per your request) along with a 2.73 gear, it is going to have some issues like this. At 55 mph, cruising at light throttle with 2.73's, the rpm's are just too low to for a full lockup, in my opinion.
Your converter is tuned for full lockup (zero slip) because I believe it would cause premature converter lockup clutch wear with the 2.73's when cruising and partially locked up.
Locking up the converter at 45 mph will make this issue worse on deceleration, but may feel fine with everything loaded on acceleration. We can set it to whatever you want, even though I wouldn't recommend it.
We go through a series of events to help break in a new converter, and also never lock up a new converter while tuning any wide open throttle. The converter isn't your issue/problem.
You need some gears man! Call me if you have any questions.
--Chad
10-22-2014, 02:45 PM
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The LCA and torque arms are stock so I'll check them out in the morning and see. I had to take my car back to them because ses light came on and threw code p0757 and they deleted it out. They also lowered my lockup a little by my request. Dave Steck (DSX) is who did the tuning and he's pretty reputable. Has his and the builders advertisements on the beginning of some of the txy2k14 videos. They also have quite a few cars on YouTube they have tuned. But I am still wondering if it is the tune or it wasn't broken in properly.
10-22-2014, 05:13 PM
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David,
The chattering noise you are hearing in the rear end is from the bucking from the camshaft cause by several things working against you with this setup (as I warned you initially). When you have a decent sized camshaft, you will get some bucking on deceleration at near idle RPM's...when you lock up the converter at lower speeds (per your request) along with a 2.73 gear, it is going to have some issues like this. At 55 mph, cruising at light throttle with 2.73's, the rpm's are just too low to for a full lockup, in my opinion.
Your converter is tuned for full lockup (zero slip) because I believe it would cause premature converter lockup clutch wear with the 2.73's when cruising and partially locked up.
Locking up the converter at 45 mph will make this issue worse on deceleration, but may feel fine with everything loaded on acceleration. We can set it to whatever you want, even though I wouldn't recommend it.
We go through a series of events to help break in a new converter, and also never lock up a new converter while tuning any wide open throttle. The converter isn't your issue/problem.
You need some gears man! Call me if you have any questions.
--Chad
The chattering noise you are hearing in the rear end is from the bucking from the camshaft cause by several things working against you with this setup (as I warned you initially). When you have a decent sized camshaft, you will get some bucking on deceleration at near idle RPM's...when you lock up the converter at lower speeds (per your request) along with a 2.73 gear, it is going to have some issues like this. At 55 mph, cruising at light throttle with 2.73's, the rpm's are just too low to for a full lockup, in my opinion.
Your converter is tuned for full lockup (zero slip) because I believe it would cause premature converter lockup clutch wear with the 2.73's when cruising and partially locked up.
Locking up the converter at 45 mph will make this issue worse on deceleration, but may feel fine with everything loaded on acceleration. We can set it to whatever you want, even though I wouldn't recommend it.
We go through a series of events to help break in a new converter, and also never lock up a new converter while tuning any wide open throttle. The converter isn't your issue/problem.
You need some gears man! Call me if you have any questions.
--Chad
10-22-2014, 05:30 PM
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I thought the wheel hop issue was fixed after I put the OEM ws6 springs in yesterday. But today I was on some good concrete and it wheel hopped pretty bad. I'm going to try the bottom hole on my LCA brackets tomorrow, but I think that with the rear raised about 2" higher than it was that it would be too low. I'll try the top after that, then I'll call BMR after that to see what they suggest to fix it.
05-09-2015, 12:40 AM
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I figured I would go ahead and update this thread because I've ran across so many other threads where they never come back and say what fixed it and what the problem was. It ended up being a couple of things by the time it was said and done. As Bob from BruteSpeed said, my factory torque arm was flexing and causing the wheel hop issue. So I bought an adjustable torque arm and fixed that issue, well then another arrived. At wot I could feel a small clanking like something was lightly slapping the bottom of the car. It would also feel like something was coming through the bottom of my center council when I'd hit big bumps.
So I put the car in the air and found two places where the new torque arm was hitting the bottom of the car when bottoming out and on wot pulls. The issue was because the torque arm was too close towards the drivers side due to my car being lowered. So I measured the rear end and it was a 1/4" more towards the drivers side. So I ordered an adj panhard bar, centered the rear end, set my pinion angle and all is fixed.
Thanks again for everyone's input and hopefully this thread will help out anyone else that runs into this problem.
So I put the car in the air and found two places where the new torque arm was hitting the bottom of the car when bottoming out and on wot pulls. The issue was because the torque arm was too close towards the drivers side due to my car being lowered. So I measured the rear end and it was a 1/4" more towards the drivers side. So I ordered an adj panhard bar, centered the rear end, set my pinion angle and all is fixed.
Thanks again for everyone's input and hopefully this thread will help out anyone else that runs into this problem.
05-09-2015, 06:10 AM
#15
It's good to see you got the problems solved. Bob
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