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How To: Rebuilding a Borg Warner 4404

Discussion in 'Transmissions & Transfer Cases' started by gavin, June 21, 2008.

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  1. Gray97

    Gray97 New Member

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    I know this thread is over a year old, but I have an interesting problem. I have a 97 Mountaineer with 5.0 AWD. I was experiencing the knocking noise coming from the transfer case (4404). I first took off and rebuilt the front drive shaft (CV 6 bolt) but still had the knocking. I left the front shaft off and drove it in 2WD for almost 2 years with no problems (other than the parking-emergency brake issues). I finally took the transfer case off to replace the viscous coupling unit. The fluid in the transfer case was a deep blackish color and overfilled, so I assumed the viscous coupling and leaked its fluid. After replacing the VC and seals (kept the same bearings and chain), I took it for a test drive.

    Now, I can hear some rattling, scraping noises coming from the transfer case and when I really romp on it, I still get the clunk noise. I think I need to replace the chain as it seemed to have some slack in it when I reinstalled. Wish I would have replaced the first time, but my mistake. The original chain only has one blue link, but everything I have researched is telling me to use the HV-070 with 2 links.

    I took the front drive shaft back off expecting to drive it in 2WD again until I can replace the chain. Now, the output to the rear seems to slip. Barely got it back to the driveway. This one has me stumped. Why would the rear be slipping? Maybe the VC I replaced it with is bad, or...?
     
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  3. gavin

    gavin Elite Explorer

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    heh, so here... a year ago or so? I had the same issue with lack of movement when front driveshaft wasn't installed.
    I couldn't figure out the "why" part since, essentially, the rear should get direct drive from the input shaft. I wish I had more insight on that, but sadly I don't.
    I believe it was on one of the new VCs, too. Where did you purchase from? Do you remember the manufacturer?

    When you get the clunk? I currently have a clunking noise if, going fast enough at a high enough RPM, and I abruptly let off the gas or just burp the gas. Doesn't always occur, and seems conditions need to be just right. I thought it was the front sway bar end links, but those have been replaced with no change.

    As for the chain, I contacted Anaheim Gear some years back with the same question. Their response:
    Now, the 070 is actually a single link wider, but that's what I put in.

    Scraping and grinding sounds like a toast bearing.
    That's what I had when I didn't pay attention and left a snap ring on a bearing that shouldn't have had a snap ring. The bearing fell apart.
     
  4. gavin

    gavin Elite Explorer

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    So I may be optimistic a little hastily, but I replaced the CV joint on the old front driveshaft and installed it, and I haven't (yet) been able to reproduce the clunk noise.
    Though I did only drive a couple miles, I was up to ~45 and actively trying to reproduce it.
     
  5. Gray97

    Gray97 New Member

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    I believe I purchased the VC from American Powertrain Warehouse about 1 year ago and finally had the time to swap it out. I get the clunk if I romp on the gas either from a stand still or accelerating hard from a slow speed. I haven't tried anything at high speeds yet..still paranoid that more damage will be done until I find the problem. Before the rebuild, it would clunk very easily, but it ran great in 2WD with the front axle removed.

    I plan on getting the 070 chain and when I tear it down again, I'll check the bearings. It still has the original bearings, but I already have the replacements ready to go. I don't know if it sounds like a grinding bearing, it is more of a slapping and scraping, only when I am accelerating. When I am coasting, I don't hear it. At least I don't think I hear it. I did see a lot of slack in the chain when I reassembled it, so I am assuming it is slapping against the chain guides.

    I'll do some more research on the transfer case assembly and find out why it is slipping in 2WD. I guess another check (before I tear it down again) would be trying to get the rear wheel to spin and see if it transfers to the front.
     
  6. Gray97

    Gray97 New Member

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    I had replaced the CV joint on the front driveshaft already, before I changed out the viscous coupling. So the front driveshaft had a new CV and u joints but never used until now. I'm sure I will check it again...
     
  7. gavin

    gavin Elite Explorer

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    I got one of mine from American Powertrain also.
    If I decide to get another one, I may go the drivetrainamerica.com or autoplicity.com route. More expensive, but they are (supposedly) Motive Gear not whatever American Powertrain (and cobratransmission.com, and loads of others) sell.
    http://www.drivetrainamerica.com/4473625001-borg-warner-4404-viscous-coupler/
    http://autoplicity.com/1699018-motive-gear-bw4404-viscous-coupler

    I'll report back tomorrow after getting some more driving in with the new CV on the driveshaft.

    oh, well hmmm...
    Another known cause for a clunk from stop is the rear driveshaft slip joint.
    When it gets dry there can be some play that can cause a clunk at acceleration or moving from a stop.
     
  8. CDW6212R

    CDW6212R Hauls the mail. Elite Explorer

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    Also check the torsion bar key(pad) on the 95-97's, those can wear enough on the frame to begin to make noises. It's been years since reading about that, so my I forgot the symptoms other than noises.
     
  9. Gray97

    Gray97 New Member

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    Thanks. I did a torsion twist many years back and replaced the keys. I think they are still in good shape, but I am always listening for new squeaks and noises...
     
  10. Gray97

    Gray97 New Member

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    Here is the latest update. If you remember, I had replaced the viscous coupling but was still having problems (scraping/rattling noises, and slipping in 2WD after removing the front drive shaft). I tore it down again to replace the chain. I replaced it with the 070 chain, which was much tighter. I was surprised to see how much slack was in the old chain when comparing them. I inspected the internals completely because I found some metal shavings that looked pretty fresh. I noticed that the chain has been scraping against the internal ribs on the inside of the case (front output). After disassembling and reassembling, I noticed that I had installed the front output gear/sprocket upside down. This was causing a misalignment on the chain sprocket at the front output and letting the chain scrape the ribs. Luckily I didn't drive it too much in that condition. I reassembled everything with the new chain and it is running like a champ. I've only driven it about 50 miles so far, but have tested it at speeds up to 65mph, under fast acceleration from a dead stop, and towing a light trailer. The only thing I notice is the start of some vibration when approaching 70mph, which is probably an unbalanced drive shaft. I didn't mark the drive shaft, so it is probably out of balance.
     
  11. gavin

    gavin Elite Explorer

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    Thank you for the update.
    In my case, the rumbling/grumbling continued shortly after the first rebuild, though admittedly (if you read through the whole thread) you would see that I screwed up on the first rebuild and ended up with a grenaded bearing or two. That was the first VC replacement.
    Then a couple years ago, I went to the junkyard and got another TC, though it had (iirc) around 100k miles on it. Well, I swapped it in by grumbling persisted.
    So I put in yet another TC in the original t-case, and swapped it back in.
    It was okay for a little bit, then rumbling/grumbling returned.
    Then last year, I replaced my tires as they needed replacement anyway.
    Immediately noticed an improvement on the first drive with new tires.
    Sadly, that did not last long either.
    I'll try rebuilding this junkyard case, since I didn't do anything to it other than pop it open to inspect it, and possibly go for that Motive Gear replacement VC.
     
  12. CDW6212R

    CDW6212R Hauls the mail. Elite Explorer

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    I am expecting you guys to figure these out well soon.

    I've got two AWD trucks now, and planned on only converting one to A4WD with a BW4406 TOD. I'm going to swap a 302 into my V6 truck eventually, and I think I'll go to the A4WD on that also. I'd like to leave my spare truck as AWD, and rebuild a BW4404 for it.

    So do post up what parts are the best to use if you get a chance, and any new tips or tools to get etc. Regards,
     
  13. gavin

    gavin Elite Explorer

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    I'm hoping I figure it out soon too :(
    Granted, it's been acting up for 10+ years and nothing has grenade, it sucks having an extremely crappy ride.
     
  14. CDW6212R

    CDW6212R Hauls the mail. Elite Explorer

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    I bought my "new" 98 Limited with it not having the front drive shaft installed. They had removed it seven years ago to stop the noise it made, and never tried to figure out what it was.

    I'm about to swap my known good drive shaft and axles, plus hubs brakes, into the new truck. I'll know quickly whether it was the drive shaft, or the AWD TC. My one AWD until now has been great for 107k miles, so I've been pleased with the AWD. I haven't had to rebuild one yet.
     
  15. gavin

    gavin Elite Explorer

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    @Gray97 do you happen to remember if there was "slop" on the input shaft, between the VC and bearing?
    Curious, because I noticed it the last time I replaced the VC in the original TC, and I also noticed it when I tore my junkyard TC apart last weekend.
    I could move the VC about 1/4" or 1/8"

    Also curiously, the HV-070 is actually one link skinnier than the OEM chain; 20 on the 070 vs 21 on the OEM.

    Anyway, ended up getting the Motive Gear VC. Unfortunately, I apparently ended up tossing the 2 old VCs as I really wanted to compare them. Or I just, erm, misplaced them somewhere in the garage.

    That junkyard t-case presumably had a stretched chain. It wasn't visibly apparent, but the amount of play between the front and rear outputs is much less with the new chain.

    Hopefully I'll get a chance to swap them out somewhere in the next couple weeks.
    Though I'm thinking I may just wait until my Old Man Emu leaf springs come in, then take a week off work to take care of all that. Since I have plenty of PTO to use.
     
  16. Gray97

    Gray97 New Member

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    I don't remember feeling any slop on the input shaft and VC. I do remember a lot of slop on the output due to the stretched chain. The new chain was much tighter. So far, the new VC and the new chain did the trick on my Mountaineer. I have put around 1200 miles on it without any problems.
     
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  17. gavin

    gavin Elite Explorer

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    Interesting... thanks!
     
  18. CDW6212R

    CDW6212R Hauls the mail. Elite Explorer

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    Gavin, have you had any new issues with your AWD, and did you make any parts list, sources etc? I've got to rebuild one now I think, my 98 after 40k is binding up on all tight turns. I think the VC has locked up, and it's like being in 4WD all the time.

    I'm going to remove the BW4404 from my 98 Mercury, rebuild that, and swap it into my 98 Limited. I think with over 200k it should get almost all new parts, bearings, VC, chain, seals etc. What blind seal puller would you suggest to buy to do the job?
     
  19. gavin

    gavin Elite Explorer

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    I think I've come to the conclusion that the transfer case was never the issue. I still have some vibrations, but I have no clue wtf they are coming from, and I think I've kinda gave up on looking for it. It's been there for so long, and I can't actually find anything wrong and nothing has exploded yet. Though I do think at least part of the issue is a combination of tires, suspension, and crappy pavement. There's one or two strips of road where there's virtually no vibration, yet vibration exists everywhere else. Vibration also isn't visible from an action cam mounted on the t-case skid place via magnet or one mounted on my hitch.

    Viscous Coupler: BW4404 TRANSFER CASE VISCOUS COUPLER FITS '95-'01 5.0L EXPLORER & MOUNTAINEER 4404-625-001
    Drivetrain America is almost twice the cost of this one, although I see their price has dropped to under $300 now.

    HV-070 Chain (2 blue links) BW4404 BW4424 BW4427 TRANSFER CASE CHAIN 1.25" WIDE WITH 2 BLUE LINKS BORG-WARNER HV-070

    I believe the bearing and seal/gasket kit I bought from Rock Auto. Well, one of them.
    I believe this is one of them I used: BW4404 TRANSFER CASE REBUILD KIT FITS '95-'01 5.0L EXPLORER & '98-'01 MOUNTAINEER WITH SPEEDO IN REAR CASE (BK4404)

    Not sure on the differences, but it does appear they have a different kit for a t-case without the speedo.
    BW4404 TRANSFER CASE REBUILD KIT FITS '95-'01 5.0L EXPLORER & '98-'01 MOUNTAINEER WITH NO SPEEDO IN CASE (BK4404A)

    I never attempted that tiny bearing again, but I did end up getting a blind hole puller kit.
    Similar to this: https://www.amazon.com/8milelake-Internal-Bearing-Puller-Hammer/dp/B016W8GSQ8

    There's probably some special tool for the large ring/clip for the output shaft, but I never looked for one.
     
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  20. CDW6212R

    CDW6212R Hauls the mail. Elite Explorer

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    Thanks Gavin. I browsed for the Motive Gear VC, but didn't see one. The BW part number(4473625001) is used for the brands I did find, so I couldn't see if the Motive Gear exists now at all.

    I'm fairly sure my issue is the viscous coupler of my TC. I bought this 98 without a front driveshaft, so the TC was suspect then. With known good parts from my Mercury, it's gone 41k miles. About six weeks ago I noticed a mild noise or slight popping in the front, I figured suspension, CA's or TRE's. I found the left axle with a dry rotted CV boot, it's the first I bought in 2004, from Autozone. I swapped that two weeks ago, and the noise was gone for two days. I then replaced the four CA's, had been planning to do it when the popping got worse.

    Leaving to go to the alignment, the popping seemed more like a binding, I immediately thought front carrier, and when I got back I swapped that. The carrier was very worn out, pinion bearing is toast. The noise was gone but it still was binding noticeably. So I pulled the front drive shaft, and the binding is gone, smooth as can be. I think the TC is failed in a locked condition, which is wearing out the front drive parts. I could rebuild a D35 carrier, but I think the transfer case is the real issue I have now.

    I appreciate the links, I'll search a little more tomorrow and decide on the parts, and the bearing puller. Did you not need any special seal drive tools? I've used a large 3/4" socket set for many things over the years, I haven't yet needed to buy the right driving tools.
     
  21. gavin

    gavin Elite Explorer

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    A half-assed test if you wanted.
    Can't recall if I put it in Neutral or not but, lift one front tire.
    You should be able to rotate the tire. It will certainly be stiff and take some umph, but it should turn slowly.
    There's probably some spec on nominal required torque, but I never could find anything. Some videos on youtube for Land Rovers (or was it Range Rovers?) they would put some weight on a long pipe and see how long it took for it to rotate down. They used something like 20 pounds on a 3ft pipe and it would take 5 minutes to drop, they figured was good.

    Alternatively, if you have a strap wrench, might be easier to get a better handle on rotating the driveshaft itself.

    Other than that, usual suspect would be cv joint on driveshaft if it isn't a known-good shaft.

    And yeah I had found that Motive branded VC once, but it was out of stock. Wouldn't surprise me if they are all manufactured by the same company though.

    I do have some standard bearing and seal drivers, but that would have been about the only "special" tools I used. And those seals were relatively easily seated so even an appropriate sized socket would work. For bearings, you could probably just use the old bearing to beat on. I've used that method before.
    None of the bearings were super tight fit though, except that one tiny one.
    I do believe I used the blind hole puller on the front output shaft bearing though.
    A 2 or 3 jaw gear puller could potentially work as well if you can rotate the arms for the hooks to point outward.
     

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