under power my rear diff has a shudder is this the limited slip going bad? if so should i have it rebuilt or replace with different one? how would a full posi rear diff do in a bronco? it is 4x4. can you even get a 1/2 ton full posi rear diff? any info would be great. thanks.

 

The limited slip "trac-loc" setup in the differential as Ford called is what GM folks call "posi". If you want a full-blown locker, there are many available. Just depends on how much you want to spend and whether or not you want it to engage automatically or be selectable by the driver. Selectable lockers are engaged by either a mechanical link, compressed air, or electricity.

 

check your driveline and ujoints. i just had my rear driveshaft bolts come loose on me and it did exactly what you are discribing here..

by the way please go into your control panel on the forum and fill out your signature with info on your rig. this helps us when offering answers.

 

Most probably an u-joint issue, if you ran out of luck, then the ring might have lost a tooth (it happened to me once), wich requires replacing both ring and pinion.

 

not the u-joints, and a ring gear feels different i had one go bad before too.and i will fill out my vehicle info

 

pull the rear drive shaft and drive in 4wd to see if the problem is still there? if its the ring/pinion the vibration will still be present.

I bet your cardon joint on your rear driveshaft is shot and causing out of balance. when this happens the e4od will go into limp mode, and feel like its low on power.

 

well it doesnt shudder with normal driving its only when you floor it from a stop or floor it going up hill otherwise it as smooth as can be.

 

then that sounds like an issue with the tranny perhaps. have you checked the fluid in the tranny and tcase?


have you taken your rear driveshaft off and had it looked at?

 

well the reason i think it rear diff is because my 01 f150 had rear limited slip and it had the clutches go out in it and it felt the same. but that was a warranty issue then. and no i have not taken the rear drivshaft out yet im only home everyother weekend as i drive truck and im out on the road now thats also why sometimes it takes me awhile to respond to comments on my posts. thanks for the help.

 

Sure sounds like low/reverse clutches are slipping.

 

Sounds like the lockup torque converter shudder if yours is an E4OD. Mine used to do that before the lockup went out completely and tripped a code. Give me an AOD any day

The only time the rear differential works is when turning. Driving in a straight line wouldn't put any torque on the clutches.

 

i forgot about the rear diff only locking up in turns, is there any additive that can be used to help with problem till it can be replaced?

 

if its already locking up you need to pull it and get it replaced. if you continue down this current path your spiders will be destroyed and could take out the Ring & Pinion.

 

If your TQ Conv has not been replaced, then it probably needs to be. But, from your description of the problem, the TracLock clutches and TorqConverter are not the problem. If it shudders on a hard take off from a stop, then the TQConv is not slipping its clutches and shuddering. At a take off, the converter is open and the clutches do not come into play. The strategy for the lockup is by speed, which on my 93 is not until ~45 MPH. Neither are the Trac Lock clutches shuddering, in a straight line, because they are not slipping against one another, only in a turn or traction problems. I would think that a missing or bad tooth on the gears would show up as a noise at road speed, not just under hard load (.02). I think I would go with with one of the driveshaft/yoke/tranny clutch packs etc.

BTW, I would take the E4OD any day, all day, over the AOD. They had problems just like the early AOD/4R70W trannys, but once fixed are a great tranny. Again my .02

 

You guys have to realize that limited can chatter in a straight line. I can all but gurantee that the tire diameter from the left rear to the right rear are not exact, which means that the side gears are turning at a different rate. Measure your tires and see how far off they are. Then take into consideration some of the road conditions. Crowns in the road will require some input to the opposite direction creating some drag on the clutches in any limited slip.
Gear oil that is fatigued and broken down will cause the rear differential clutches to chatter, especially going straight. See the clutches only provide resistance to the side gears, and during a turn they have to slip. More clutch pressure will create more pressure, but worn clutches will slip to the point where you will not feel the slip.
Straight away acceleration can and will cause the "chatter" that is so common with these LS units.
This can and will happen from a dead stop as well as from a roll.
Now, to add to this, a weak spring can allow some axle wrap, and if the u-joint is binding or it causes some increased angle, you will have this same issue, but to the point, the LS unit can cause this same issue.
More often than not, a bottle of friction modifier is needed, even when store bought gear oil is used with friction modifier already added.