Body Shake Or Clutch Chatter

[Issaquah Bronco]

I have a 1972 sport with 2.5" lift,302 with original 3 speed, that shakes like a banshee when letting out the clutch into first gear or reverse. I've read everything on the forum but haven't seen any answers that fit my scenario. Here's what has been replaced and I'm sure I"ll forget a few things... New: Luc Clutch, flywheel, TO and Pilot bearing, clutch linkage bushings, driveline, rear leaf springs and bushings, u-bolts, u-joints, engine mounts and nothing has improved!!!! If I put it in low range the problem goes away completely???? Any new ideas would be appreciated. Running 33" tires with a 3.50 differential. Once the clutch is out all is perfect and likewise if you let the clutch out with no throttle all is good

 

[broncnaz]

Welcome.
Have you replaced the transfer case bushings? While 33's and 3.50 gears are not the best of combos with a 3sp you should still have a smooth enguagement with a new clutch.

 

[LOVNBRONCOS]

I had a friend install a new clutch and had the same problem, took it to a shop and had to replace the clutch due to grease on the clutch from the install. I was told to much grease when the pilot bearing was installed. Hope that's not your problem

 

[Issaquah Bronco]

Thank you Broncnaz. I have not replaced the transfer case mounts yet, but have watched them with a go pro camera and don't see any noticeable movement. They are on my to do list. The guy at my local transmission shop, wasn't able to figure it out either, but suggested that I increase the angle between my rear driveline u-joint and the yoke on my third member. He said when there is NOT ENOUGH angle i.e. almost straight and that this can cause binding... What do you think?

 

[dave67fd]

Give us some more detail on the rear suspension setup. Who's leafs are you running? If your running lift blocks thats a key problem. Seeing as there new try loosening the leafs at the spring eye bolts and let them relax abit and snug back up. Make sure their torqued properly and not too tight. As mentioned the 33's, 3-speed and 3.50's are a big contributor.

 

[Issaquah Bronco]

I had a friend install a new clutch and had the same problem, took it to a shop and had to replace the clutch due to grease on the clutch from the install. I was told to much grease when the pilot bearing was installed. Hope that's not your problem

I installed the clutch myself and took extra care to make sure the new flywheel was clean and that there was no excess grease on anything. Rear main seal had no leakage either. Thanks for the thoughts though....

 

[Issaquah Bronco]

Give us some more detail on the rear suspension setup. Who's leafs are you running? If your running lift blocks thats a key problem. Seeing as there new try loosening the leafs at the spring eye bolts and let them relax abit and snug back up. Make sure their torqued properly and not too tight. As mentioned the 33's, 3-speed and 3.50's are a big contributor.

My leaf springs are from Toms Bronco Parts (5 leafs, supposed to provide better than original ride) on old 2" blocks that look to be in fine shape. U-bolts are new. I'll try loosening and re-tightening. What should I torque them to? Obviously I didn't do that to spec before

 

[broncnaz]

Yeah pinion angle could be a issue although I would think that a new driveshaft would or should have covered it up. but then again anything can happen. I know I could use a better pinion angle on my 73 witha 2.5in lift but I dont have any issues with clutch chatter or ujoints. But if your running blocks as well then as was said that could be a big prat of your problem.

First Id check the torque on your ubolts many times after 100 miles or so on a new install they will loosen up and need to be retorqued. Id recheck at about 500 miles as well. The torque for your ubolts depends on size. 1/2" is usually about 70 ftlbs. 9/16" about 100 Ft lbs. 5/8" 125 ft lbs.

 

[Issaquah Bronco]

Yeah pinion angle could be a issue although I would think that a new driveshaft would or should have covered it up. but then again anything can happen. I know I could use a better pinion angle on my 73 witha 2.5in lift but I dont have any issues with clutch chatter or ujoints. But if your running blocks as well then as was said that could be a big prat of your problem.

First Id check the torque on your ubolts many times after 100 miles or so on a new install they will loosen up and need to be retorqued. Id recheck at about 500 miles as well. The torque for your ubolts depends on size. 1/2" is usually about 70 ftlbs. 9/16" about 100 Ft lbs. 5/8" 125 ft lbs.

Thank you, I'm inspired! I have half inch u-bolts that I just checked and they only have about 35 lbs of torque on them.. I will tighten them down more and see if anything changes.

 

[Justafordguy]

Another thing that just came up with another member here was the firewall/clutch pedal mount flexing. This is a weak spot and if the flex it too much it will cause clutch chatter. Have someone push the clutch while you look under the hood at the firewall where the clutch pedal bracket bolts through. If you get a good bit of movement this may be your problem. Many have had to build a brace to stop the flex.

 

[hammer189]

Just a thought. Pull the rear drive line and put the transfer case in 4 hi. Driving it like this may show if it's in the clutch area or a problem with the rear driveline/pinion angle/axle. No real experience, just a shot in the dark. Good luck.

 

[JB Fab]

I have experienced that in two rigs, I was sure it was the clutch. it was just the limited slip in the rear diff. needed friction additive. took about 200 miles of city driving to clear up.

 

[Fairlane514]

What was the condition of the front bearing retainer on the transmission? If its excessively worn or gouged the throw out bearing will be cocked and not put equal pressure all around the pressure plate

 

[Issaquah Bronco]

Thank you, I'm inspired! I have half inch u-bolts that I just checked and they only have about 35 lbs of torque on them.. I will tighten them down more and see if anything changes.

Well I loosened and then re-tightened the u-bolts down to 70 lbs. No change.. Still shakes like a banshee.

 

[Issaquah Bronco]

Just a thought. Pull the rear drive line and put the transfer case in 4 hi. Driving it like this may show if it's in the clutch area or a problem with the rear driveline/pinion angle/axle. No real experience, just a shot in the dark. Good luck.

This makes great sense... I'll remove the rear driveline and see how it behaves? That way I can eliminate axle wrap, driveline angle, and clutch maybe. If it still does it, I guess I would need to assume there is something wrong with my new clutch install:-(

 

[WASP1971]

Looking forward to hearing your results. I have some chatter as well but I just put the +1" body mounts in and installed a longer adjustable clutch rod. Still figuring it out...

 

[Harley]

Have a similar if not the same issue but havent started to diagnose. Interested in your results

 

[dave67fd]

My leaf springs are from Toms Bronco Parts (5 leafs, supposed to provide better than original ride) on old 2" blocks that look to be in fine shape. U-bolts are new. I'll try loosening and re-tightening. What should I torque them to? Obviously I didn't do that to spec before

Stop looking at your clutch. I will bet money that your issue lies mainly with the leafs and block combo. I had the same exact problem and setup you had. 3-speed, 3.50 gears and 35" tires. I went to 32" tires, Duffs 5 leaf pack, kept the 2" blocks and new U-bolts, new driveshaft and proffesionally installed entire clutch system. Helped very little but still did it (35 to 32" tire was probably the only thing that helped slightly). Toss the blocks, sell the 5 leaf pack and go with a WH's or similar 10 or 11 leaf progressive spring pack. Also seriously Consider a gear swap to at least 4.11's. The gear swap alone will also probably cure it.

If you don't you will have to live with the vibration.

PS-I also added Duff kicker bars with little to no improvement.

 

[blazinchuck]

i just went through all of this, new fly wheel and swapped to a diaphragm pressure plate.

 

[Harley]

I was thinking Fly Wheel and Pressure Plate. I have other issues as well. What is a good strong clutch for a daily driver/week end warrior?