Transmission or t-case (Something's wrong)

[jewlz]

Hello, this is my first post in the forum, and i regret that this is the way i introduce myself... but I'm a long time reader, first time poster.

The Truck
My Explorer is a 1998 XLT with 4.0L SOHC, Automatic Transmission, and ControlTrac Transfer case.
The 4x4 has been disabled by the removal of the front driveshaft forward f the transfer case, this was done because auto4x4 would constantly engage due to different tires on the front from the rear (previous owner's doing).

The Current Problem
As i was driving a couple nights ago, i detected an intermittent grinding and clunking noise under what seemed to be the very centre line of the vehicle. This noise occurred around 50km/h and went away when the vehicle was stopped, or sped up past 80, or shifted into neutral. The best description i have of the noise, is to think of repeatedly trying to shift a manual transmission into reverse while rolling forwards (not a healthy noise).

The Confusion/Possible Solution
This afternoon, after the short ride home from work, i decided to try my one and only trick to solve the problem. Hoping that for some miraculous reason, the problem laid in the transfer case's shift position (who knows why i thought this) I sat in the driveway, in neutral, and shifted into LOW range, waited a few seconds, then shifted back out. The whining from the transfer case during shifting, followed by a satisfying clunk, told me that i was back in HIGH mode. I haven't extensively tested the results of this act, but a quick drive around the block yielded no such noise. (not to jinx it)...

My Request
Would you all kindly post your opinions on

• what the problem causing this sort of noise could be?
• Whether it is more likely Transfer case or the Transmission
• if my simple HIGH to LOW to HIGH could help or hurt things, Why, or Why not

Thankyou so much, i'll update with the status of my truck!

-Jewlz

 

[swetrid]

There is a gear in the front of the transfercase that wears and can cause your noise. Sometimes you will lose reverse and get a grinding noise also.

 

[drdoom]

I am quite familiar with this noise. In my 97, it was caused by worn shift fork bushings ($1.35 each), which in turn caused the HI/LOW collar ($39.90) to wear...as swetrid stated above, it is a gear, and that is most likely what you hear grinding. One thing that is easy to check, drain some transfer case fluid. Mine had little specks of white plastic in it, so I knew my problem was the plastic bushings. I rebuilt my case, and it is working fine now. Let me know if you need more info.
http://www.explorerforum.com/forums/showthread.php?t=182071

EDIT: As for your HI/LO/HI trick, this can get you back in gear, but I'm telling you it is what I call "The Beginning of The End"...sooner than later, you will have only LOW range...the collar's teeth, and the fork's bushings, will be too worn to go back into HI range. (Ask me how I know.)

 

[jewlz]

Thanks for the input, i'm hoping to have an oportunity to do some work on the truck in the new year... I'm glad to hear, though, that you agree that the tcase could/likely is the culprit, since i have no budget for a new transmission, that would just mean junking the car. As for the rebuild how much internals do you think would need to be replaced?

Thanks

 

[drdoom]

Well...

As for the rebuild how much internals do you think would need to be replaced?

Thanks

That could certainly vary, from just what it needs, to putting a bunch of other stuff in while you have it out. Without having it in front of me, I could only guess: I would say at the very least you will need the shift fork guide bushings and a HI/LOW collar. You could also have issues with the case halves, as they are prone to wear. There are upgrades that you can do to your case, that address some inherent weaknesses in the design. These are well covered in Glacier's rebuild diary. As for what I did personally, I just did the fork bushings, collar, and a seal kit. Including fluids & shipping costs, I spent less than $90.00 US. This was because of financial reasons...I really had no other choice. If funds would have permitted, I would have taken my case halves to the machinist, and added bronze bushings for the shift rail. I also would have purchased an enhanced shift fork. I know this is not a very good answer...there are many variables.

 

[jewlz]

Of course, that makes sense. It seems like a waste for me to do anything more than the minimum since 4wd is already disabled. Something that i'm curious about is modifying the transfer case to operate as a dummy (sortof like the bronco II's had) since i don't ever really plan on purchasing a new front drive-shaft/replacing any other things that will degrade on the 4X4 system.

At the moment it's all about striking a balance between preserving the vehicle, and reducing maintenance costs