transfer case grind/clunk on acceleration
Cross-Country
Joined: Feb 2001
Posts: 93
Likes: 2
From: St. Louis USA
transfer case grind/clunk on acceleration
[updated:LAST EDITED ON 02-Apr-02 AT 09:40 PM (EST)]Got a 99 Expedition 4x4, 62k miles. I believe this has the Borg Warner 4406 xfer case? I am assuming/deducing that this problem is a transfer case issue...
Anyway, here goes: Drive for about 20-30 mins at highways speeds, then exit hwy and stop. If I accelerate quickly within a minute or so of driving hwy speeds, I notice (at best) a grinding and (at worst) a clunk-clunk-clunking coming from the front of the vehicle. The longer time I spent driving at highway speeds prior to exiting, the more it sounds like clunking rather than grinding, like something trying to engage but not quite getting there.
This grinding/clunking occurs from about 15mph thru 30mph, then goes away completely above that speed as you continue to accelerate. Also, if I let the vehicle sit, or just stop in traffic for 5 mins or so, the problem fades and/or goes away. Ambient temperatures outside seems to affect it as well; drove a 1000 mile trip from 90 degree weather into 35 degree weather, it occurred much more in the hot climate than the cold climate.
Help!!! Haven't towed anything with this vehicle, most of the miles were simple highway miles. Well maintained. Is it possible that the transfer case is already giving way at 62k? Are there any straightforward things to look for in diagnosing this?
Anyway, here goes: Drive for about 20-30 mins at highways speeds, then exit hwy and stop. If I accelerate quickly within a minute or so of driving hwy speeds, I notice (at best) a grinding and (at worst) a clunk-clunk-clunking coming from the front of the vehicle. The longer time I spent driving at highway speeds prior to exiting, the more it sounds like clunking rather than grinding, like something trying to engage but not quite getting there.
This grinding/clunking occurs from about 15mph thru 30mph, then goes away completely above that speed as you continue to accelerate. Also, if I let the vehicle sit, or just stop in traffic for 5 mins or so, the problem fades and/or goes away. Ambient temperatures outside seems to affect it as well; drove a 1000 mile trip from 90 degree weather into 35 degree weather, it occurred much more in the hot climate than the cold climate.
Help!!! Haven't towed anything with this vehicle, most of the miles were simple highway miles. Well maintained. Is it possible that the transfer case is already giving way at 62k? Are there any straightforward things to look for in diagnosing this?
Postmaster
Joined: Jul 2001
Posts: 4,038
Likes: 3
From: South Kitsap County, WA
transfer case grind/clunk on acceleration
Have you checked your front, rear and transfer case fluids lately? Even if you have there's a possibility that a leak could have developed or you have a bad internal oiling mechanism. Without sufficient fluid flow the xfer case will wear rapidly. A sign of this would be a good level with lots of aluminum flakes in the xfer case fluid.
I am not familiar with the 4406 but it should be similar to the auto-shift-on-the-fly units produced by Borg Warner in the past. Aluminum case with steel parts and an internal pump. If the pump goes bad, then you would have the chance of a bad case after a few thousand miles.
You may want to check the whole driveline, especially the u-joints (if applicable), as these usually cause clunks.
-Kerry
I am not familiar with the 4406 but it should be similar to the auto-shift-on-the-fly units produced by Borg Warner in the past. Aluminum case with steel parts and an internal pump. If the pump goes bad, then you would have the chance of a bad case after a few thousand miles.
You may want to check the whole driveline, especially the u-joints (if applicable), as these usually cause clunks.
-Kerry
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