Grinding Sound from Transfer Case

[Overland]

Short story first:

When decelerating (actually engine braking with no foot on gas) at over 50 mph there is a high pitch grinding noise coming from the transfer case. It sounds like gears trying to mesh while spinning at high speed. I can avoid this by A) putting the transmission into neutral until I am going slower then 40 mph or B) keep a slight amount of throttle so the engine rpm doesn't drop below around 1500.

The longer story:

The truck is a 97' Explorer XLT AWD with Auto transmission. After a few days of the grinding noise I was finally stranded on the side of the road. I took my foot off the gas while going down a slight slope in the road. The grinding noise started and then abruptly stopped but when it did I had no drive Tran. I coasted to the side of the road and had the truck towed home.

After towing it home I started the truck and found that it was mobile again. I figured out that when the truck was hoisted onto the tow truck the steep incline must have put the transfer case back into gear. I later confirmed this when I pulled the transfer case out and popped it open to find a broken gear reduction fork. I replaced it ($39) and was mobile again without the grinding noises but instead a thud. Now under the same conditions as the previous grinding noise I was getting a slite thud or clank. It was just like something spring loaded was pulled and then released causing it to slap into position.

After about 1000 miles of this the truck has returned to the grinding noise. Obviously the broken gear reduction fork was a problem resulting from some yet unknown cause. I'm planning on pulling the transfer case out again before it leaves me stranded, but I don't really have any idea what to look for that could be causing my problem. The symptoms also seem unique after Googling it for over an hour. Any help would be greatly appreciated.

 

[GJarrett]

It is a part in your transfer case called a "range slider". You need to replace that part along with the fork and/or inserts that go along with it (sounds like you just replaced the fork). If you don't get it fixed it will eventually wear enough to not engage. Mine just started it at 161,000 miles. I saw the part and the wear. Over time, the ends of the teeth wear down on the ends and the tcase gear slips on it.

Call Heath at Stephens Transmission in Chesnee, SC to get the parts. (864)461-4583. This ought to fix your problem. If you noticed fluid leakage, you may also have worn holes in your tcase now at the seals and need to get that fixed too.

I also answered this same question three other times; try searching for "range slider" to view those threads.

EDIT: I see you are a new member. Welcome to the site. There is a wealth of information here and you can use our "Search" function to answer almost any question you have.

 

[Overland]

I'm glad I'm not the first to have this problem. However I was unable to find the other threads by searching under "range slider". I'll keep looking, but if you have any more information about fixing this problem I'd love to hear it.

Thanks again!

 

[GJarrett]

Make sure you are using this site's search in the toolbar right above these posts, and not the Google web search. Anyway it doesn't matter.... you'll just giet the same info I just gave you.

 

[RammaR]

Overland,

I just rebuilt the BW4405 t-case on my '96 a couple of weeks ago. Its really not that bad of a job, however besides the 'range slider' you should really look at either replacing the front and rear transfer case shell halves, or having them re-machined at a local shop. The real cause of what's happening is that the range fork moves back and forth along a guide rod that is sits into holes machined into the t-case halfs themselves. Because the housing is Aluminum it wears out over time, mine died at 153k miles, but if you only replace the fork and gear then problem may well happen again very soon. The fork doesn't engage the slider gear by much, so just a little slop is what causes it to slip out of place and start grinding as you described.

I got my case halves from here:
http://www.omegamachine.com/html/BW4405_front_case_repair.html

Let me know of any questions you have, I got a lot of help from others here when I tackled it.

Good luck.

 

[GJarrett]

Good point... a fluid leak wasn't mentioned, so I didn't address that (I would suppose that there will be at least some fluid leakage if the case is wallowed out). Mine was okay so I didn't tackle that, but holes wallowing out in the case is at least as common a problem as the fork and slider.

 

[ScottT80]

It is a part in your transfer case called a "range slider". You need to replace that part along with the fork and/or inserts that go along with it (sounds like you just replaced the fork). If you don't get it fixed it will eventually wear enough to not engage. Mine just started it at 161,000 miles. I saw the part and the wear. Over time, the ends of the teeth wear down on the ends and the tcase gear slips on it.

Call Stephens Transmission in Chesnee, SC to get the parts. (864)461-4583. This ought to fix your problem. If you noticed fluid leakage, you may also have worn holes in your tcase now at the seals and need to get that fixed too.

I also answered this same question three other times; try searching for "range slider" to view those threads.

EDIT: I see you are a new member. Welcome to the site. There is a wealth of information here and you can use our "Search" function to answer almost any question you have.

Gerald, thanks for the info. Out of curiousity, are you close to Chesnee? I'm just down the road in Spartanburg. I had this problem a year or so back, and pretty much just parked the truck... finally getting around to fixing it. What do the parts cost? The range slider and fork?

 

[gavin]

the 4405 is behind the v6, correct? He did state he has the AWD t-case (BW4404).. meaning it shouldn't have a gear reduction, since it's 1:1 with the tranny, and shouldn't have a shift-fork since it has no low-range.

 

[RammaR]

The 4405 is behind the v6 in my XLT. You make a good point about his AWD setup with a 4404 - not sure on how its guts are setup. Do the AWD explorers have a 4wd hi / lo switch of any kind?

 

[98Explorer4x4]

I just had experienced this problem on my honeymoon this past week up at Grand Marais, MN. Thanks for those who posted this problem!

 

[ExplorerDMB]

moving to Transfer Case Section

 

[gijoecam]

the 4405 is behind the v6, correct? He did state he has the AWD t-case (BW4404).. meaning it shouldn't have a gear reduction, since it's 1:1 with the tranny, and shouldn't have a shift-fork since it has no low-range.

Indeed, either he found the broken part in a 44-05 automatic 4wd case, or he has AWD and it was a figment of his imagination.

I assume he mistakenly called it AWD when, in fact, he has A4WD (Automatic 4 Wheel Drive).

And yes, it's all a common problem in high-mileage Exploders. Time for a new t-case, or at least some new parts from Omega Engineering.

-Joe

 

[Lazerskull]

Short story first:

When decelerating (actually engine braking with no foot on gas) at over 50 mph there is a high pitch grinding noise coming from the transfer case. It sounds like gears trying to mesh while spinning at high speed. I can avoid this by A) putting the transmission into neutral until I am going slower then 40 mph or B) keep a slight amount of throttle so the engine rpm doesn't drop below around 1500.

The longer story:

The truck is a 97' Explorer XLT AWD with Auto transmission. After a few days of the grinding noise I was finally stranded on the side of the road. I took my foot off the gas while going down a slight slope in the road. The grinding noise started and then abruptly stopped but when it did I had no drive Tran. I coasted to the side of the road and had the truck towed home.

After towing it home I started the truck and found that it was mobile again. I figured out that when the truck was hoisted onto the tow truck the steep incline must have put the transfer case back into gear. I later confirmed this when I pulled the transfer case out and popped it open to find a broken gear reduction fork. I replaced it ($39) and was mobile again without the grinding noises but instead a thud. Now under the same conditions as the previous grinding noise I was getting a slite thud or clank. It was just like something spring loaded was pulled and then released causing it to slap into position.

After about 1000 miles of this the truck has returned to the grinding noise. Obviously the broken gear reduction fork was a problem resulting from some yet unknown cause. I'm planning on pulling the transfer case out again before it leaves me stranded, but I don't really have any idea what to look for that could be causing my problem. The symptoms also seem unique after Googling it for over an hour. Any help would be greatly appreciated.

I'm curious how's your transfer case these days?
I had the EXACT same problem, and I've been able to find various users with this same thing... you let off gas around 40mph or higher and you get
a noise... that is a pre warning that something in the case only has a few days left before it snaps.

I have several ideas. If you are at high speeds, and the 4 wheel drive auto is trying to engage the other wheels when you let off the gas, maybe the computer is glitching and trying to do that, and wouldn't that explain the sound? it's a sound of gears grinding without a clutch engaged.

So what would cause this? The GEM module? Someone else said to find the wiring harness to the transfer case and unplug it, wait ten minutes and
replug it and see if that works. Have you tried that?

I'm curious how things are going for you. I was disabled on the freeway far from home. I had no choice but to tow it to a shop, and then guy there seems "okay" as far as mechanics go. He wants 1,300 to repair everything inside and reinstall it.

I guess that 1,300 includes trying to install a new shift motor which didn't do anything.

 

[Lazerskull]

Indeed, either he found the broken part in a 44-05 automatic 4wd case, or he has AWD and it was a figment of his imagination.

I assume he mistakenly called it AWD when, in fact, he has A4WD (Automatic 4 Wheel Drive).

And yes, it's all a common problem in high-mileage Exploders. Time for a new t-case, or at least some new parts from Omega Engineering.

-Joe

How many miles can you expect to get out of a transfer case? I am at 250,000K and I believe the current transfer case was installed around 175,000 miles.