Bronco Is All Messed Up! Help!

[404PageNotFound]

Hi. I'm new here. Background on this situation. I bought her to be a winter truck (snowly new england hell), and possibly a plow vehicle. Since then the truck grew on me (so useful!) and I want to repair it, but I'm a former honda guy, so i dont know squat about these trucks.

As of right now the bronco gets a horrible shaking/vibration at about 25mph and up. I know the rear main seal on the tranny is gone and the exhaust tail pipes fell off. Two of the starter bolts came off, and I replaced those. but i dont know if one of the old ones went into the bell housing or the seal around the rear axle diffs went.

It's not driveable because of the rear main seal being gone, but I dont know what's causing the nasty vibration. I just had the U-joints in the rear redone before it all fell apart. I also have no clue what gear ratio the rear axle is (i can't find the "tag" on the diff housing the salvage yard told me to look for. Is there any place to look for the tag or to find out which ratio it is? My options apparently are 3.08, 3.55 and 4.10. All I know is that it's a 1991 Eddie Bauer Edition with a 5.8 and an over drive transmission.

I'm really assuming the worst on this one. If anyone can help me it would be much appreciated.

Thanks,
Mike.

NOTE: the owners manual says H9 means a 3.55 traction lock. so that solves that.

what would be causing that bad vibe though?

 

[STLKIKN]

Since you say the u-joints were replaced ( assuming they were done properly, and aren't damaged from poor installation...)
Check;
That your rear shaft u-joint straps are tight,
That the bolts for the double cardan to rear output yoke are tight,
That the slip joint isn't worn out,
That the rear output yoke isn't loose,
That the diff yoke isn't loose
And that the ball in the double cardan is tight,
And finally that all grease zerks are well lubed.
Also make sure you don't have a loose wheel.

Post back with your results.

 

[Shadow_D]

Something else to check is your tires / wheels. Have them re-balanced and checked for bent rims. When you put them back on the truck move the front tires to the back and the back ones to the front.

 

[CADster]

As of right now the bronco gets a horrible shaking/vibration at about 25mph and up. I know the rear main seal on the tranny is gone and the exhaust tail pipes fell off. Two of the starter bolts came off, and I replaced those. but i dont know if one of the old ones went into the bell housing or the seal around the rear axle diffs went.

what everyone else said

more info would be better and tracking this down -

is the vibration from the front steering ? or the rear driveline/wheels ?

is it constant at all speeds, or only during accelerating/decelerating ? can you speed out of it ? does it do it when the truck is coasting in neutral ?

if its not a tire/rim thing, im thinking driveline.. maybe a shot bearing.

I also have no clue what gear ratio the rear axle is (i can't find the "tag" on the diff housing the salvage yard told me to look for

chalk front tires. jack the back of the truck up. mark the drive shaft with chalk ( the marking kind). mark tire in line with driveshaft mark. rotate tire one chalk rotation, count driveshaft chalk rotations ... it will get you close enough to know - 3:90 and 4:11 are hard to tell apart

i will guess that its 3:55

 

[jayjs]

[-o< Torque converter?

 

[404PageNotFound]

well, i hope its just the torque converter.. it'll give me an excuse to replace the transmission outright.

other than that.. bleh.

 

[latindog369]

while rebuilding my 89, I found out that Ford used plastic guides in the tranfer case, When worn, the whole assembly tilts and could be the problem. Because it not running it will be hard to trouble shoot without opening the case.
>-