Solved - Front Differential Thumps and Jumps= Bad things happen in 4wd | Ford Explorer Forums - Serious Explorations

  • Register Today It's free!

Solved Front Differential Thumps and Jumps= Bad things happen in 4wd

Prefix for threads that contain problems that have been resolved, and there is an answer within the thread.

Turdle

DIY stunt double
Staff member
Moderator
Elite Explorer
Joined
June 16, 2003
Messages
31,544
Reaction score
3,218
City, State
Humboldt, KS
Year, Model & Trim Level
2000 Mounty
I posted here because the front diff is a stock component, however, the transfer case differentials sub forum might be a better place for this discussion.

Included is a video showing what has to be excessive front diff movement.
Why?

Since I first noticed the issue I have tried a different front diff, new cv axles and even swapped original cv axles back into the 2nd diff. While it is entirely possible I got a 2nd diff with the same issue, I still want to run it by the board.

Recently I removed the front drive shaft to service it thinking the slip yoke might be dry. I removed the front u joint caps to grease them, and did see some wear on the cross from the u joint pin rollers, it felt "snaggy" but freed up with new grease. In the video the front joint looks ok. Could it be grabbing the diff and throwing it like this?

Another "might mention this" thing I might mention-the little clips holding both the half shaft on passenger side and cv shaft on the driver side are not there, from the removal-re installation. What do those clips really do besides make it harder to remove the shafts?

Driving in 2wd is fine as far as I can tell. The only time this happens is under load in 4wd -and sharp cornering in 4wd.

I should have shot a video of backing out of the driveway right after this. In 4wd mode, wheels cut hard right backing up very slowly it really jumped hard.:eek:

Pretend you are hanging upside down under the truck. Look at the diff--0:47 and 0:59 it really bounces good. It almost looks like it is broken from the mount.
 



Join the Elite Explorers for $20 each year.
Elite Explorer members see no advertisements, no banner ads, no double underlined links,.
Add an avatar, upload photo attachments, and more!
.





i watched your video but i'm not sure what i'm looking for (and watching it upside-down made me a little nauseous). i'm gonna re-watch it right side-up.

question:
this is a 4WD (not AWD) vehicle? if it's 4WD, driving it on dry payment in 4WD will cause the front diff to bind up when you have the wheels turned because not all the wheels can turn at the same speed. eventually something has to give to release the stress.

edit. i re-watched the video and see the front dif jump around. is that what you are referring to? if so, it is hung on rubber mounts/bushings so some movement seems normal.
 






i watched your video but i'm not sure what i'm looking for (and watching it upside-down made me a little nauseous). i'm gonna re-watch it right side-up.

question:
this is a 4WD (not AWD) vehicle? if it's 4WD, driving it on dry payment in 4WD will cause the front diff to bind up when you have the wheels turned because not all the wheels can turn at the same speed. eventually something has to give to release the stress.

True, however an open diff should allow different wheel speeds. The open diff should be what gives.
Thump also happens in a straight line 4wd acceleration. Even on snow--gravel wet pavement etc.

What you are looking at would be the very bottom ( or top if the video is rotated) of the view. That is the bottom of the front diff pumpkin. It should not move, thump, and bang like that.
This "was" an AWD vehicle but is now Manual shift 4wd via a transfer case swap to B&W 4406.
 






True, however an open diff should allow different wheel speeds. The open diff should be what gives.
Thump also happens in a straight line 4wd acceleration. Even on snow--gravel wet pavement ect.


This "was" an AWD vehicle but is now Manual shift 4wd via a transfer case swap to B&W 4406.

yeah but an open diff allows for different wheel speed between the wheels on the same diff, not 2 different diffs. so i think one front wheel trys to match the rears (which are not open). it's like having a locker in a 2wd vehicle. somethings gotta give when you go around a corner. you shouldn't drive in 4wd on dry pavement for that reason. but you're right, on snow or gravel it shouldn't make noise.
 






+1
You need wheel slippage with 4wd-this is normal for a 4wd vehicle. Gonna break something if you keep it in 4wd when wheels can't easily slip...

Bill
 






I only shot the video on pavement so the camera would stay clean.:shifty_ey

I know I am not supposed to use 4wd on dry pavement. ;)

Does this on gravel. Does it on wet. Does it in a straight line under load.

This is not my first mountaineer v8 with a 4406 swapped in. Turdle ( with both LSD and later a locker in rear) did not do this. That is why I am asking for some help.

:D
 






I only shot the video on pavement so the camera would stay clean.:shifty_ey

I know I am not supposed to use 4wd on dry pavement. ;)

Does this on gravel. Does it on wet. Does it in a straight line under load.

This is not my first mountaineer v8 with a 4406 swapped in. Turdle ( with both LSD and later a locker in rear) did not do this. That is why I am asking for some help.

:D

understood. just trying to get the more obvious possibilities addressed first.
 






Hey Jon what type of front shaft do you have?
 






understood. just trying to get the more obvious possibilities addressed first.
Thanks!
Hey Jon what type of front shaft do you have?

It is a Double cardaan at the transfer case end with a d 35 yoke end. To be honest I was [MENTION=165306]Stang5lgt[/MENTION] 's place when we did the swap. He "grabbed something that would work", to which I said "OK" :D
 






Pinion is loading up just like the rear will do. That is why Ford uses that big bushing in the back(by the pinion) to allow the pinion to move up and down. If they didn't do this you would feel the violence when it loaded up.
 






id eventually like to get my hands on a hi pinion dana 44, and just cut out all of that stuff..ill leave the ifs stuff for the duramax which sees highway.
 






after swapping 2 front diffs and 4 cv axles to no avail, it turns out the differential thump and jump was caused by something wrong in the 4406 manual transfer case.
 






Do you know exactly what was wrong (or have a very good idea)? I try to turn each interesting post like this into an "education" post for myself, so I'm genuinely curious. It might help me figure out a future problem for myself.

Thanks,
 






Do you know exactly what was wrong (or have a very good idea)? I try to turn each interesting post like this into an "education" post for myself, so I'm genuinely curious. It might help me figure out a future problem for myself.

Thanks,

+1!!!

Please don't mark this as "Solved" when you really haven't told us what to look out for when we do our own 4406 upgrade.

Thanks,
 






Do you know exactly what was wrong (or have a very good idea)? I try to turn each interesting post like this into an "education" post for myself, so I'm genuinely curious. It might help me figure out a future problem for myself.

Thanks,

I thought I posted but my ATT uverse service intermittently cuts me off at the most critical time. A lot. But that is for another rant.






+1!!!

Please don't mark this as "Solved" when you really haven't told us what to look out for when we do our own 4406 upgrade.

Thanks,

Sorry guys. I have not ever cracked a transfer case open. I have no idea what is wrong with it, just that it is wrong.

Compared to the replacement though, it is "looser" and makes some sandpaper like noises when turned by hand. The shift positions do not seem to fall into place as they do on the replacement case either. There is less of a dampened feel to the bad one.

However, I must add that this transfer case had been thru a good hard life before I got it. It worked hard for me also, for a while. :)
 






Bad news, as I will have to remove the "solved" marker from this thread.

After much coaxing of MLB, ( I threw her shoes at her) and sweeping off all the snow with the garage o'cedar broom, my little luv muffin and I went out for a country snow cruise. Everything was going great. We were giggling and sliding , had the roads all to ourselves seein how's we live out here sorta off the grid. I had the LED light turned on, and we could see quite a few critter tracks, it was lookin' squatchy. Good times!


All was well, that is, until I gave it some real power ( more than just a little fishy tail power, kinda like floored power) on a snow covered back road, slick enough to make the ABS kick in. Bang Bang said the front diffy. A loud, truck shaking, knock the cigs off the dash, am I gonna have to walk home type bang. All of the sudden lil muffin quit giggling and that makes me pretty upset. And to top it off, Mule wasn't happy. You know what happens when the Mule isn't happy. No my friends, things are not going well at all.


I manually shifted back to 2wd just fine. At least the bang doesn't pop it out of 4wd like it did before so I guess I did get one thing fixed.

The problem is either the diff or a cv axle binding. I am going to try to acquire these as soon as I can.
 






i watched the video, i noticed something odd,,

at both times the front diff jumped, it was as you straightened out , after making a turn,,

when the cv's get back to going the same speed, as pressure is let off the front diff from cornering,,
jack up the front, on one side, spin the wheel see if the diff allows it to spin or if it resists,,
could be an indication
 






i watched the video, i noticed something odd,,

at both times the front diff jumped, it was as you straightened out , after making a turn,,

when the cv's get back to going the same speed, as pressure is let off the front diff from cornering,,
jack up the front, on one side, spin the wheel see if the diff allows it to spin or if it resists,,
could be an indication

Good eye Pete. It does seem to occur after coming out of a turn, as a matter of fact tonight it was after completing a 3 point turn,abs sliding to a stop then punching it in a straight line.
 






Take a hard look at the tiny bearing in the tube as well, I posted picks of it in another thread , the mountaineer had this issue and broke the lip of the housing tube , good time to grab a set of 99 ranger half shafts and the seals clips bearings and a set of AVMs
 



Join the Elite Explorers for $20 each year.
Elite Explorer members see no advertisements, no banner ads, no double underlined links,.
Add an avatar, upload photo attachments, and more!
.





Solved!

After trying a different transfer case, and drive shaft I finally came to the conclusion something in the front diff was causing this.

However, I had already replaced the front diff and cv axles. The one piece I re used was the culprit.

I went and got another complete 373 front diff, stuck bearings, seals and even new bushings. Stuck it in and we now have a good working 4wd truck!


The one piece I reused previously--the torque bracket. The unit we removed has a bushing so worn I can move it by hand. when it was in the truck, just a screwdriver would move the torque bracket almost 1/2"

This worn bushing was allowing the diff to rotate rearward, binding the drive shaft.
 






Back
Top