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Ok trying to get my driveline angles parallel and it's looks impossible.
My trans is angled down and so is my rearend before I started to check angles. All stock, except poly trans, poly pinion and solid/poly engine. I can only raise the trans a little(.3 deg) and if I remove the snubber entirely and tighten it down the pinion still needs to point up 2.4 deg to match the trans downward angle.
Maybe I am doing it wrong or something, but I thought you just needed to match the angle for the pinion and trans centerline.
There was a thread on this topic very recently, and there have been many in the past.
Yah I read several of them and many go off track with no real solution that would help me. Also some of the ones I've read have to cut their bushing in half, but none seem to have to remove it completely and still aren't even close. Thx for the bump I guess.
Yah I read several of them and many go off track with no real solution that would help me. Also some of the ones I've read have to cut their bushing in half, but none seem to have to remove it completely and still aren't even close. Thx for the bump I guess.
Not nearly as critical as you'd think. My angles are way off due to Trans swap and I have no issues.
Not nearly as critical as you'd think. My angles are way off due to Trans swap and I have no issues.
I drag race so other than vibes and u-joint life I'd like to reduce drivetrain loss.
I was hoping it would be as simple as shimming the snubber or trans mount. finally found a good thread with some info, it looks like I'll have to shim the pig down or make a new snubber bracket and maybe drop the engine.
i got as close as i possibly could by cutting the snubber bushing in half and shimming up the tranny.i replaced the tranny dipstick assembly with a ss braided flex and that allowed me to go up higher with the tranny shims.i did not get it perfect but with new u-joints all around i eliminated all vibration at all speeds.good luck.
i got as close as i possibly could by cutting the snubber bushing in half and shimming up the tranny.i replaced the tranny dipstick assembly with a ss braided flex and that allowed me to go up higher with the tranny shims.i did not get it perfect but with new u-joints all around i eliminated all vibration at all speeds.good luck.
Yah for now I can shim the trans 3/8" and still have enough clearance for my comfort. I bought 3 metal & 2 rubber washers to layer that fit over the top male snubber part so that end won't bottom out on the pinion bracket and won't be 100% solid. Still even with both those I won't gain much and both will be pointed down. I plan to change the spring next year so I'll drop the pig n x-mem and try shimming it.
Yah I read several of them and many go off track with no real solution that would help me. Also some of the ones I've read have to cut their bushing in half, but none seem to have to remove it completely and still aren't even close. Thx for the bump I guess.
I reworked my diff mounting bracket. It has to be in something you've read as this has been a recent hot topic.
I have the exact same problem, and am attempting to solve it by using a double cardan joint on my driveshaft. I've already modified my pinion isolator cushions and experimented with different angles etc. The double cardan joint is my last hope, I expect to get it installed Friday and will let you know if it worked. This is what it looks like:
I really hope to come out of this with less vibration, so it's a little disturbing to read that there could be more at high speeds. I really don't know what else to do at this point.
I really hope to come out of this with less vibration, so it's a little disturbing to read that there could be more at high speeds. I really don't know what else to do at this point.
Alum or CF should dampen more. I only had some vibe and not really the reason I bought CF or want to correct my driveline. I went with CF because I know alum needs to be bigger diameter to be the same or stronger than steel and my Fastshafts CF one is only 2 1/4". Still I have not drove with the CF shaft yet and when I do I'll also be putting on some alum 3" halfshafts as well.
The rear pinion angle is determined by the rubber isolator at the front of the diff and the 2 rubber mounts on the crossmember that attaches the diff to the frame. When I did my LS/Richmond 6 speed swap, I put the trans as high as possible. I cut the front rubber diff isolator to about 1/8". I also used new rubber diff crossmember mounts. The old ones were crushed. I was able to get it within 1/2 degree and no vibrations at all.
There's a thread over on another forum where the front diff mount was redrilled where it attaches to the diff in order to tilt it up too. The rubber mount was left as is in that case.
Last edited by Garys 68; Sep 10, 2014 at 09:23 AM.
It's a lot of trial and error IMO. I tried the poly mount in the rear and went back to rubber. I still had vibrations. It turned out that the torque on the pinion bushing bolt was a major factor. I finally got it to stop buzzing with about 10 ft lb on the bolt. Then it loosened up a few times and the vibs came back. Finally I torqued it to 10 again and I double the nuts with a nylon lock nut on the end. I haven't had to touch it in years.
So my advice is loosen up the pinion nut and test drive. See if it changes for better or worse. Then take note if it's better on the gas or off. This will give you the direction you need to go. Obviously on the gas if the vib goes away, your pinion needs to go up and vice versa if it goes away on deceleration.
Good luck! It's a PITA bit once you got it, you got it for life
It's a lot of trial and error IMO. I tried the poly mount in the rear and went back to rubber. I still had vibrations. It turned out that the torque on the pinion bushing bolt was a major factor. I finally got it to stop buzzing with about 10 ft lb on the bolt. Then it loosened up a few times and the vibs came back. Finally I torqued it to 10 again and I double the nuts with a nylon lock nut on the end. I haven't had to touch it in years.
So my advice is loosen up the pinion nut and test drive. See if it changes for better or worse. Then take note if it's better on the gas or off. This will give you the direction you need to go. Obviously on the gas if the vib goes away, your pinion needs to go up and vice versa if it goes away on deceleration.
Good luck! It's a PITA bit once you got it, you got it for life
I had a looong talk with Mike Dyer about this and he doesn't want me to do that, says that he's sure it's right and that if it wasn't it'd be spraying diff lube. I'm really at my wits end, I installed the double cardan set up to day and it made little or no difference. Maybe it's something other than u-joint noises but the same noise gets louder or softer depending on the angles.
I got so beaten down from trying to fix this that I took a break from it and concentrated on other things since the double cardan driveshaft didn't help at all.The last thing that I did was put in a new pinion mount and the stock driveshaft and it decreased the noise/vibration to a barely tolerable level(prior to this I had cut down the pinion mounts). So, I've done just about everything else that needed done other than this and decided today to re-measure the angles and see if there's anything else I can do. I came up with 2.2 down on the front yoke, 2.3 down on the rear yoke, and .9 down to the rear on the driveshaft. This give a front u-joint angle of 1.3, and a rear u-joint angle of 3.2. As discussed previously in this thread, if the driveshaft were level in this case the angles would be equal and cancel each other out. Apparently this isn't an unusual set-up because I found this on Street and Performance's website:
Now if I had the stock engine sitting on the stock mounts I'm guessing it would be a degree or so less than my LS1 is which would give me around .3 front driveshaft angle with the rear angle not that much different than it is now. So shouldn't every C3 have the same problem I have, and every LS1 equipped C3 even more so?
First off, most of the information online is for live axles that move and change pinion angles. Yours will not change much, just a little flex in your mounts. You just have to measure really well to get the angles close so that both joints are traveling the same speed - no vibration. The previous threads here covered the subject about as well as it can be - with words. Pretty much every LS swap is different, I made my own engine adapters to lower everything to help with the big a$$ 6 speed.
Today I adjusted the pinion angle to 2.2 down, the driveshaft is level and the transmission yoke is a 2 down. Needless to say the angles are very close, it was really pretty simple. I was kind of slow to understand this subject, I guess I'm getting senile. Now if the weather would clear up I could go for a nice test drive...
Driveline angles
