Banging and Thumping when turning with 4x4

[r6jon]

1997 Ford Explorer Limited, 6cyl, 130k miles, Auto/4x4H/4x4L functions properly on Control Trac system. Light duty useage throughout lifetime/ female driver.

Recently there has been a terrible clunking, groaning and poping noise coming from the transfer case and front diff when turning slightly.

I know very well all about binding that occurs when using 4x4 on dry pavement - this is NOT the same thing. I'm talking about terrible clunking noises that shudder the whole car even with only 1/4 turn on the wheel with 4x4 engaged. You can even hear groaning when going straight with 4x4 engaged - but turning the wheels and loading up the driveline makes it really vicious.

keep in mind that I am the origonal owner of this car and I am not describing any of the typical noises associated with the 4x4 system. I'm talking about noises that would make any man cringe and beg for mercy!

Anyway, my cousin is a ford tech and he is almost convinced that the clutch pack in the transfer case is shot. He also thinks that the Amsoil ATF I put in the transfer case may have caused the clutch pack to fall apart and cause this banging when slipping/engaged.

One thing he did that supports this theory is powerbrake with the 4x4 engaged. Basically gas and brake HARD at the same time so the car can't move but the driveline is fully loaded. The banging noise started up even though the car wasn't moving! This suggests that the clutch packs may be slipping and fubar'ed.

I'm trying to make the right decision before I pay or commit to droping and dis-assembling the transfer case. I've been searching this forum for hours for the same symptoms and I can't find a conclusive thread as to what it may be.

I would greatly appreciate any help I can get! Thanks in advance. I'm sure this isn't the only 4x4 Explorer with high miles that has had this problem...

 

[dogfriend]

I'm confused about your cousin's diagnosis. It seems to me that if the clutch pack is shot, then you wouldn't get any binding because the front driveshaft wouldn't be engaged.

Also, I have been running AMSOil ATF in my Transfer Case for ~26k miles. I haven't had any issues. It meets all of the Mercon and Mercon V specs, so I'm not sure why it would cause the clutch pack to fail.

It sounds to me that you have a problem where the 4wd is engaged when it shouldn't be. You could test for this by hooking up a scanner and look for the amount of clutch engagement commanded by the GEM.

 

[gijoecam]

Welcome to the Explorer Forums!!

Agreed.... I'm not so sure about it being the transfer case.... how could it be banging and clunking when nothing's moving? (And by power-braking, I assume you meant standing on the brakes, then loading up the gas pedal torquing the drivetrain over, but the wheels aren't moving at all, right?)

With the switch in 4 auto, it doesn't make any noise when turning, correct? If not, we can rule out any front axle or CV problems.

-Joe

 

[r6jon]

I'm confused about your cousin's diagnosis. It seems to me that if the clutch pack is shot, then you wouldn't get any binding because the front driveshaft wouldn't be engaged.

Also, I have been running AMSOil ATF in my Transfer Case for ~26k miles. I haven't had any issues. It meets all of the Mercon and Mercon V specs, so I'm not sure why it would cause the clutch pack to fail.

It sounds to me that you have a problem where the 4wd is engaged when it shouldn't be. You could test for this by hooking up a scanner and look for the amount of clutch engagement commanded by the GEM.

Yes, indeed. But his argument is that the clutch is slipping and causing the chattering/hopping/binding to be so bad. I did all the research on the Mercon and Mercon V compatibility with Amsoil before I made the fluid change and I agree with you - it should be compatible. I really don't want to believe that it has anything with the fluid, however he insists he's seen it before.

He says this used to happen in earlier models all the time because the vent tube for the trans and xfer case were shared causing MerconV from the trans to condense and fall back into the xfer case pan. Over time, the Mercon V destroys the clutch packs in the xfer case and causes the same symptoms that my explorer is having.

I don't believe it though. It just seems way to aggressive to be the clutchpacks. I imagine that one of the teeth is missing from the drivchain sprocket or something like that - again, he says no way.

The truck functions fine in 2wd (auto 4wd) without any issues. No clunking or anything. If you drive quickly in a circle and the 4x4 (automatically) engages, you get the banging though.

He plugged the scanner into the port and it read 13% duty cycle when manual 4x4 was selected. This number seems odd, but he said it's what the GEM is requesting, not what it's getting... so it's not a helpful diagnostic number? I don't know...

I need to decide if I should pay for him to drop the xfer case and look through it. It's a good deal because he's using the shop at "family" rates or some crap. He quoted me the whole job with the part (if it's only the clutchpack) for about $550 which seems to be dirt cheap...

It's not the job I would like to tackle on my back in the middle of a Northeastern winter.

 

[dogfriend]

My recollection is that I got about 13% when I read that PID with my scanner in 4 High also.

I don't know if I can help - the few posts that I have read with clutch pack problems had different symptoms than you are describing.

I have read about some problems with the transfer case banging, but it wasn't related to the clutch pack - it is a problem where the bearing surfaces in the case get distorted and then the shafts get out of alignment. See if this might help:

http://www.explorerforum.com/forums/showthread.php?t=66666&highlight=transfer+case

 

[gijoecam]

The fact that it's banging only when engaged makes me think that it's an internal issue, but not for the Mercon reasons (AFAIK, they don't share a common vent tube).

I think IZWack had a thread with similar issues a while back (last spring, maybe). He posts the pics all the time of the broken ball-ramp piece in the clutch. If it was happening when it was DISengaged, I'd say yeah, the whole clutch is toast. The fact that it happens only when engaged tells me it's got something to do with the electromagnetic part of the clutch itself, probably not the shafts or the clutch-pack.

Dangit.... can't find that thread or pics at the moment.... will try again later...

-Joe

 

[r6jon]

The fact that it's banging only when engaged makes me think that it's an internal issue, but not for the Mercon reasons (AFAIK, they don't share a common vent tube).

I think IZWack had a thread with similar issues a while back (last spring, maybe). He posts the pics all the time of the broken ball-ramp piece in the clutch. If it was happening when it was DISengaged, I'd say yeah, the whole clutch is toast. The fact that it happens only when engaged tells me it's got something to do with the electromagnetic part of the clutch itself, probably not the shafts or the clutch-pack.

Dangit.... can't find that thread or pics at the moment.... will try again later...

-Joe

yes please try to find the pictures and the thread, i can't find any more information that i have found already.

one more thing i would like to add, it sounds like a metal on metal chatter when going slow and turning. as if you had brake rotors or drums that were rusty type sound. the banging only comes when you push it.

i'm concerned about the diagnosis also, i don't think it's correct..

 

[Glacier991]

I think this is the thread you are looking for:

http://www.explorerforum.com/forums/showthread.php?t=142207

 

[gijoecam]

I think this is the thread you are looking for:

http://www.explorerforum.com/forums/showthread.php?t=142207

That's it!! Thanks!

-Joe