Transfer Case/Front Drivetrain Issue (Binding/Banging/Clunking)

[fatboy0186]

I've got an issue with what I believe to be the 4x4 system. I've been on this forum for years and have tried to narrow it down via searching, but I'm asking for some help on this one. My truck is a '96 XLT, 4L, 2wd with 4wd auto switch.

Driving in 2wd, I can feel and hear (what I think is) the transfer case binding. At say 25mph, there is a bang/thud appox. every 1sec and I can feel the truck jolt. The thud is at my feet. I turn the switch to 4wd Auto, transfer case engages and the thuds stop.

I used to think that after a few miles in 4wd, I could switch back to 2wd and it would stop. Well yesterday I was pulling off the interstate in 2wd, I took the exit and the t-case/front axle started screaming. Think of the sound a transmission would make if you missed 3rd gear and banged into 1st gear at speed... I quickly hit the switch to 4wd, and all was good again.

My theory is that the t-case clutch is engaged in 2wd, from either fouled electronics or a bad t-case. I've tried unplugging the connector to the case, and that does nothing. 4x4 still works, I have tested it and the front wheels do engage if I get the rears spinning. I've got many theories but I don't know where to start.

I'm open to all suggestions, as I rely on this truck for work.

 

[fatboy0186]

Nobody wants to take a stab at this?

 

[ragajungle]

Front driveshaft front joint... on know on AWD models this clanging - thudding is when the t/c engages the front DS... Might check for play there.

 

[PopRichie77]

My truck is a '96 XLT, 4L, with 4wd auto.

When you say 2 wheel, you mean Auto on the selector? If so the fluid coupling in the T/C may be bad, causing the front wheels to drive the front Dif and the front drive shaft, this puts load on the front axle u-joints and may cause then to bind some when turning.

 

[fatboy0186]

Yea its a 2wd truck, with 4auto on the 4wd switch.

Problem occurs when driving in 2wd (I notice it mainly when driving in a straight line). Sounds like the front shaft is binding, or the clutch in the t-case is engaging in 2wd causing it to bind. I'm just guessing here... At 25mph, I get a bang roughly every second.

All I know is if I engage the T-case by switching to 4auto, everything is back to normal. I plan to replace the front u-joints this weekend, but if there is an issue with the t-case I'm SOL.

 

[PopRichie77]

Is your ABS working correctly? The computer uses the ABS sensors with this type of T/C. When driving in Auto if the computer thinks a wheel is slipping it applies the the electric clutch in the T/C to stop slippage. This does bang in and out in normal operation, in snow, I personally don't like it much and switch to 4 high when it starts switching in and out. But if you have a ABS or wiring problem it will happen when it shouldn't. When you switch to 4 high you apply the electric clutch full time.

 

[fatboy0186]

I have considered the ABS, however the ABS warning light is not on.

 

[corkey]

put the Explorer up on stands , all four wheels, put the trans in neutral, and turn the back driveshaft by hand,,
If the front shaft turns too, than the t case clutch is locked up, and must be repaired

this happened to another member here, gmanpaint, and it was on account of the transfer case clutch letting go ,locking it in 4wd all the time,,

 

[PopRichie77]

If I understand you correctly the T/C clutch applies intermittently. Does the ABS light come on when the key is first tuned on and then go out, if it does, It would indicate the ABS is ok. I would then check the wiring to the clutch for a short. Disconnect the wire to the T/C clutch, if the problem goes away the clutch is good. I think there is a fuse that will disconnect it but not sure.

 

[fatboy0186]

I will try that this evening and let you know what I come up with.

For now, am I going to cause damage cruising around with 4auto engaged? Seems like I should be fine, just extra wear on the t-case...

 

[fatboy0186]

If I understand you correctly the T/C clutch applies intermittently. Does the ABS light come on when the key is first tuned on and then go out, if it does, It would indicate the ABS is ok. I would then check the wiring to the clutch for a short. Disconnect the wire to the T/C clutch, if the problem goes away the clutch is good. I think there is a fuse that will disconnect it but not sure.

ABS light on when key is first turned, then cuts off as it should.

I strongly believe the tcase clutch is engaging intermittently in 2wd, causing the issues I am having. 4wd mode all is well.

I have disconnected the harness to the t-case before with no luck stopping the problem, but that may have been just the harness for the motor switch. I will look again this evening and see what I can come up with.

Thanks for the quick responses

 

[PopRichie77]

You could damage the front axle U-joints or any of the U-joints as well as damage to the T/C as this system is not meant to drive on dry payment in 4high, as far as I know. There are many different types of 4 wheel drives and none are exactly alike.

 

[PopRichie77]

Removing the T/C electrical plug disconnects power to the magnetic clutch, (brown wire) if the problem still exists, then it looks like a T/C problem, the clutch could be damaged as corkey said, be sure all U-joints are good.

 

[fatboy0186]

put the Explorer up on stands , all four wheels, put the trans in neutral, and turn the back driveshaft by hand,,
If the front shaft turns too, than the t case clutch is locked up, and must be repaired

this happened to another member here, gmanpaint, and it was on account of the transfer case clutch letting go ,locking it in 4wd all the time,,

I jacked all 4 wheels up, and turned the rear wheels with the trans in neutral, the front shaft did not move. I spun each front and the front shaft did not move either. U-joint caps are as rusty as everything else under the truck, but the joints don't look terrible.

Next is to find the fuse for the t-case clutch and pull it. I'll know on my way into work tomorrow morning if that solves the issue. If not, I am guessing I need u-joints. They will be cheaper and easier to replace than a transfer case.

 

[jestan007]

Looks like another Richmonder with the same problem as me. Did you ever find out what the problem was?

 

[wolfeman]

hello,

I know this is an old thread but I am having the exact same problems with my 96. if anyone has a solution to this problem I would love to hear about what was the problem. thanks

 

[wolfeman]

is there a fuse I can pull to test the transfer case clutch.

 

[PopRichie77]

Don't believe a 1991 has a clutch. I will check.
A 1991 has a part time TC and has no magnetic clutch.

 

[wolfeman]

it is for my 96 i havnt change my info yet

 

[PopRichie77]

Under normal driving conditions in Auto the magnetic clutch is not apply, it only applies when rear wheel spin is detected. Your selector does say -- Auto, 4 High and 4 Low--?