Body Shaking Badly

[4runner125]

I am new to this site and could use some help. I am trying to rebuild a 1972 Bronco w/302. Reverse is smooth when you let out on the clutch, 1st gear engaged shakes the entire body of the truck. New motor mounts and new clutch/fw/pplate. Not sure where to look now: rear end, driveshafts, etc. Had the shafts off, ujoints are ok. Thanks!

 

[Arikilen]

Does the speed you are moving matter? Are you referring to death wobble (tires bouncing, bushings) or something out of balance (driveshaft, tires, r&p, fp)?

 

[broncnaz]

Welcome.
Id check the transmission mounts and make sure your driveshaft is not binding many times the slip yoke will bind up. Also check the ubolts on the rear springs make sure they are not loose. Worn out spring and shocks can also be somewhat related.
Another thing to consider is that if your running big tires say 33in, 3.50 gearing and the stock 3sp. then your bound to get the shakes as the gearing is poor and the clutch is taking the brunt of the abuse.

 

[broncoitis]

Sounds like Axle Wrap to me! Worn out springs and u-joints could very well cause that. Had a similar issue on current truck and the new Springs have definitely helped to basically eliminate that problem. The new U-Bolts didn't hurt either. ;D

Good Luck!

 

[4runner125]

There isn't any speed involved, it starts after about a foot or two.

 

[Bundy]

What about with the trans in gear but the transfer case in neutral?

 

[SDlivin]

What if you ride the clutch when you start off? over rev the engine and pull through, does this lessen the violent tremors?

I had exactly this same problem. MY clutch was shot anyways so decided to tear into it.

Since I did more then 1 thing I cannot say for certain what solved it, but here is what I did;

Installed new clutch with pilot bearing, throw out bearing, etc...
Re-surface pplate
re-built TC (I do not believe this has anything to do with it)
New mounts and bushings for adpater between TC and transmission

Now it's smooth as butter, with that new clutch smell or rather feel.
No shakes at all, I can slowly release the clutch pedal with no gas and not even a slight shimmy, whereas before it felt like a 9.2 earthquake.

A few years back I had already replaced all the suspension components and driveshafts so I knew that wasn't the cause of the 'shakes'. I did thoroughly clean the mounting areas between the engine, transmission bellhousing, adapaters, and TC as some people swear that any variance in them matching up will cause problems.

Good luck.

 

[quikdrummer]

I had this problem long ago, turned out to be an oil leak at the rear main that would get on the flywheel. One more thing to look at

 

[ep67bro]

Had a similar problem it turned out to be the clutch and shot bushings/springs on the rear axle. The clutch wasn't that old but it was a cheap three finger NAPA clutch changed it to a Luk clutch and it was night and day better. Then replaced the springs and bushings and it was gone completely.

 

[Arikilen]

Someone else may be able to comment on this, but can you check if your driveshaft is binding up by putting the transfercase in neutral and lifting the rear end a little - turn the shaft by hand? (edit: mentioned earlier, sorry).

I wouldn't expect the body to shake at slow speeds with a balancing issue. I would think its a binding issue, as mentioned previously. Does the shaking increase linearly with speed?

 

[bknbronco]

good luck with this one. Sometimes there is no fix. I had the same problem so i resurfaced the flywheel, new clutch and still didn't fix it. I checked my crankshaft and it was a few thousands off center from the bell housing.....that could be my problem not sure. I just deal with it by slipping the clutch slightly. Been driving it that way for two years now. I don't believe there is a fix for mine except maybe tearing the motor down and having the crankshaft checked out. I will add that I just replaced my old clutch with the same style 3 finger one. Id maybe spend a bit more on the new style diaphragm type next time just for shits.

When I put a new clutch in it, it worked fine for the first few hundred miles but eventually came back. When I remove the doors its even worse so I put them back on. I just figure that's the way she will always be and im ok with that.

 

[Pa PITT]

..I say the flywheel needs to be turned again.