When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
So just to be 100% clear, does it go away if you put it in neutral at 70-75mph? On/off throttle same vibration?
I do find it interesting alot of the vibration threads on here are from T56 cars.
Both my T56 cars vibrate 70+mph. Mine is only speed sensitive though, doesnt matter what gear. Crazy part is sometimes it temporarily goes away. I thought it was tires/wheels but I have 3 different sets and they all do the same thing and have been re balanced. Both rear ends have all new bearings. One has new axles too. One is stock gear, other is 4.11's.
So just to be 100% clear, does it go away if you put it in neutral at 70-75mph? On/off throttle same vibration?
I do find it interesting alot of the vibration threads on here are from T56 cars.
Both my T56 cars vibrate 70+mph. Mine is only speed sensitive though, doesnt matter what gear. Crazy part is sometimes it temporarily goes away. I thought it was tires/wheels but I have 3 different sets and they all do the same thing and have been re balanced. Both rear ends have all new bearings. One has new axles too. One is stock gear, other is 4.11's.
I hope you figure it out.
Great questions. As of now, it's winter in Colorado so I cant actually road test it. It is on jackstands, with wheels removed, trying to narrow down the issue.
When I push in the clutch now, the RPMs die way too quickly to fully understand if it goes away or not with clutch in. However, previously, it did not go away with clutch pushed in.
On off throttle results in roughly same condition.
I never thought about T-56 transmission equipped cars having the most trouble.. I wonder if more people choose to full out upgrade everything in a stick car vs an auto car?
I have ruled out tires. I have replaced the pinion bearing and reset the Dana 60 gears.
My working angles appear a bit excessive since the car is lowered at 4.7*.. maybe that has something to do with it.
I know the 4.10 gears are spinning the driveshaft much quicker, which is straining everything more.
I am starting to get somewhere.
I reached out to a driveshaft company that specializes in custom driveshafts, and I ran my driveline angles by them.
They told me that the 4.7* working angles are too severe for standard ujoints, and recommended a custom cv driveshaft using a ball and cage style cv.
This is the first opinion I have received, so I plan on seeking a few more before I dump $850 on a driveshaft.
Has anyone had experience with a driveshaft like this?
You are going where I thought this might lead. The Dana 60 has the pinion nearer to the transmission and the pinion is lower than oem relative to the transmission. I tried putting spacers between the transmission crossmember and the body to reduce the working angles. Can't remember whether or not it helped.
I wonder if there's room at the rear of the transmission for that CV joint. If you did that, wouldn't it be more likely to fit with that joint at the rear end rather than the transmission?
I have also had conversations with Jeremy at Tick Performance. With the previous damage to the 5/6 gear, and replacing it on a slightly worn shaft, I probably have a problem there as well.
He doesn't deal with driveline angles, but he does deal with the 5/6 gear issue on these pre2000 T56 trans.
I am still doing a little more diagnosing, but I think I probably need both things done to make this thing drive-able again.
This is going to be an expensive journey...
Anyone else have experience with these driveshafts??
I was convinced my issue was transmission related and thus I bought a new TR 6060. Made no difference. Up on stands in 6th gear, had the same u-joint wobble at the transmission yoke. I replaced new u-joints with more new u-joints, pulled the Strange yoke, replaced it with a high end forged yoke & full rebalance, no difference. 99.99% it is a driveline issue, not your transmission. A friend of mine put a 12 bolt in his f-body without a single issue. I've driven it and it is vibration free at any speed. If I spend another dime on mine, I'm getting a 12 bolt, otherwise the original 10 bolt 3.42 is going back in.
So, I've been there and I already pizzed the money down that hole so you don't have to.
I finally bit the bullet and ordered the fancy driveshaft from The Driveshaft Shop. $970 bucks shipped because they need to make a custom yoke for my 30 spline output shaft. There's a 4 week lead time..
They are saying I should have it the beginning of May.
As a sidebar, I was in North Carolina for work last week - found some free time and drove up there. I spoke to Lee, and he gave me a facility tour! The place is huge, and they definitely know their crap. I feel a lot better after touring the place and spending an hour with Lee. I still couldn't convince him to build it faster.. hahaha.
I guess we have to wait a while to get the shaft and pop it in.
I sure hope that driveshaft solves the problem. If it does, I'm ordering one also. Did you order aluminum or steel? And do they have any damping material inside the driveshaft? That's the other thing I hate about the Strange driveshaft, it has no noise reducing or damping material in it and it's like a darn noise echo chamber and magnifier.
I sure hope that driveshaft solves the problem. If it does, I'm ordering one also. Did you order aluminum or steel? And do they have any damping material inside the driveshaft? That's the other thing I hate about the Strange driveshaft, it has no noise reducing or damping material in it and it's like a darn noise echo chamber and magnifier.
It had better solve my issue. At a thousand bucks, I am gonna be pretty unhappy if it doesn't.
I went 3.5" aluminum. The Carbon Fiber was another $500, and I wasn't about to go that ***** deep into a driveshaft!
I don't know about dampening material inside the driveshaft. I didn't know that was a thing? I did talk to Lee about noise transferring, and he explained some of it to me. He said the chrome molly shaft I have now only flexes about 5*, so most inertia and shock is transferred right into the driveline. With aluminum, it flexes about 15*, which softens the shock to the components. Carbon Fiber twists about 35*, and is the best at absorbing these shocks. He did tell me it will be night and day difference between my chrome molly shaft now and this aluminum shaft I'll see in May.
Well, the driveshaft showed up, and I got it in the car. It took some adjustment but I got everything set up like they recommend. The pinion working angle is now 0*, and the transmission side working angle is 3.7*.
I took her out and put her through the paces, and I can say I am pretty happy!!!
There is still a little vibration from 75mph to 85mph, and it is definitely worse in 6th gear than 5th gear, but it doesn't exist in 4th gear. That tells me that I probably still have some 5/6 gear flutter, but the vibration is 85% gone, and actually derivable now!!
This was definitely money well spent.
For anyone searching for driveline vibration issues in the future, do yourself a favor and bite the bullet, this driveshaft is worth double what I paid when I look at the years of frustration I have endured trying to track this issue down.
I will probably address the transmission again next winter, but I am now going to enjoy this baby all summer long..
EDIT: I should add what my final angles are..
engine is at 2.8* downward sloping from front of car to rear of car
driveshaft is at 1* upward sloping from front of car to rear of car
pinion is at 1* upward sloping from front of car to rear of car
transmission working angle is 3.7*
pinion working angle is 0*
I was also able to remove the heater hose mod on the rear springs (I did this to try to gain smaller working angles with ujoint driveshaft, but it looked silly at wheel gap. When I removed that, it settled back down to a true lowered car look. Win/win!
Last edited by FirebirdStud; 05-06-2019 at 10:03 PM.
Nope, the CV joint is only on the front of the shaft. It has a traditional ujoint on the rear, but it does not move since the working angle is zero.
I'm guessing the Dana 60 isn't offset from the trans out put. I was curious about that since you need the 0° working angle in both operating planes for that solution to work. The solution reminds me of the single side double cardan shaft used in lifted trucks and jeeps. I understand double cardans aren't true constant velocity they just split the difference, but the single double cardan shafts have the same limitation: The pinion has to be pointed directly at the transmission with a 0° working angle, and be inline in plan view with the trans (no offset allowed) or you get speed variation at the single ujoint side. If you have compound angles in the driveline, you need cv's or double cardans on both ends.
I'm guessing the Dana 60 isn't offset from the trans out put. I was curious about that since you need the 0° working angle in both operating planes for that solution to work. The solution reminds me of the single side double cardan shaft used in lifted trucks and jeeps. I understand double cardans aren't true constant velocity they just split the difference, but the single double cardan shafts have the same limitation: The pinion has to be pointed directly at the transmission with a 0° working angle, and be inline in plan view with the trans (no offset allowed) or you get speed variation at the single ujoint side. If you have compound angles in the driveline, you need cv's or double cardans on both ends.
I am not sure I understand your comment about the Dana 60 being offset from the transmission output? This Dana was made by Strange Engineering specifically for the F-body cars. I measured and set the output of the transmission exactly 1 inch offset and centered in the chassis, just like I did the Dana. Everything is perpendicular to the subframe.
Yeah, this is kind of like how the 4x4 guys reduce vibrations in lifted trucks.
The driveshaft builder said that ujoints are such high quality these days that I should have 60k miles on this ujoint before I will have to replace it. Obviously I will monitor it, but with the vast reduction in vibrations now, it is a small price to pay to actually be able to drive my car again!!
It must be a relief to finally see progress and be able to enjoy the car once again. What frosts me about this is that Strange Engineering has sold the Dana 60 units they designed to fit the F-body and should have darn well known that once installed, an acceptable driveline angle would be impossible. It was engineered to fit under the car, but not engineered to really replace the original 10 bolt and be drivable. I guess I'll follow your lead and give this a whirl in the near future.
It must be a relief to finally see progress and be able to enjoy the car once again. What frosts me about this is that Strange Engineering has sold the Dana 60 units they designed to fit the F-body and should have darn well known that once installed, an acceptable driveline angle would be impossible. It was engineered to fit under the car, but not engineered to really replace the original 10 bolt and be drivable. I guess I'll follow your lead and give this a whirl in the near future.
I couldn't be more excited, that's for sure! I have been traveling a lot for work, so I haven't gotten to really drive it yet.
Hopefully in the coming weeks I can. It snowed here in Colorado yesterday and today, so that ensures it staying in the garage a while longer.
Checked my car today. The working angle of the transmission u-joint is about 4.6*. There simply is not enough adjustment in the torque arm to get it under 3* and there isn't enough room to shim the transmission up. If you buy an S60, understand you will have the same issue. I contacted the driveshaft shop today to have them get the ball rolling on my cv driveshaft. What ticks me off as much as anything is that I wasted the money on a strange driveshaft and all of the time I wasted trying to make a part work that clearly was not "engineered" for the f-body, it was simply manufactured to fit, apparently without consideration for drivability.
Holy cow. I'm considering an upgrade to a S60, and after reading this thread, may have to re-think my plans. At least now I know that the driveshaft offered by Strange is a waste of time and I'd need to splurge on a much fancier CV jointed shaft in order to avoid the vibration issues associated w/ the larger driveshaft angles created by the S60. Sad to hear of the trials FirebirdStud endured to figure this out, but very thankful for him documenting them for the rest of us.
03-14-2019, 10:15 AM
