Transfer Case & Transmission issue/question.

[hubris]

Hello everyone, great forum and info source, thanks for being here!

I have a '95 Disco, 138k miles. I purchased it used for $2k and have been slowly fixing it up. Most of the issues appeared to be cosmetic with a few minor mechanical/maintenance issues: leaks in the power steering, old belts etc., All of which I repaired myself.

When I purchased it there was also an occasional clunk in the transmission when shifting from park to drive/reverse and also if I was accelerating rapidly and then removed my foot from the gas pedal. I had assumed it was the U-Joints. I have been driving it a little while now and there is no vibration, slipping, whining or other noises/issues, that I can find, just that occasional clunk.

I took it to a basic automotive shop yesterday to have them look at the u-joints, flush out the transmission fluid and some other minor maintenance. The u-joints were tight. The shop owner then put the Disco on a lift to try and figure out where the clunk was coming from and the noise seems to be coming from the transfer case.

Then they took a look at the transmission fluid, which I had planned on having them flush. They told me that the fluid is "burned"? Not “dirty” or “slightly burned” but “burned”. They made that distinction clear.

I was told that it appeared as if the transmission and transfer case fluids had never been changed. They then said that they would recommend against flushing them and even against a simple draining and refilling of the fluids. Apparently they feared that if they did drain them and put in new fluids it could cause the transmission to lock up entirely???

I had a neighbor, who has a lot of experience as a “shade-tree” mechanic look it over with me today, and his recommendation is to go ahead and flush out both the transfer case and transmission, change the transmission filter and call it a day. He is of the opinion that there is really not much wrong with either the transmission or transfer case, other than the clunk noise and feels that if I just take it easy it and keep the fluids good, it should last indefinitely.

I would rather not have to pay $1650-$2250 for a part, plus the service cost to have a new transfer case installed, unless I absolutely have to do it.

The reason I am posting here is to get some advice and possibly some clarifications on what issues I may be facing and what consequences I may need to face with any course of action.

I apologize for the long-winded nature of this post and am grateful for any and all replies.

Roger

 

[disco1]

Personally I'd change the transmission fluid. If it's burnt, it's due to overheating the fluid during it's life.

After the transmission fluid has been changed -- using the correct fluid, it may take several clutch engagements (5-20) for the new fluid to soak into the friction material. This can be accomplished by tapping the brake pedal while driving at cruise speed to repeatedly cycle the TCC.
In cases where the friction material has become glazed, an additive will usually give the fluid the proper coefficient to prevent the clonk. Additives come in sizes ranging from 2 ounce tubes to pint size containers.
However, if the fluid is severely burnt or shows metal contamination, the transmission will need to be removed for proper repair.

 

[hubris]

Hello Disco, thank you for the reply.

The shop was pretty specific about the main issue being in the transfer case. That said, I went ahead this morning and drained all the old oil from the case. It was almost like water....very thin, very burnt. I did not notice any metal particles, but with the magnetic plate, I suppose I really shouldn't.

The clunk is still there, but *much* quieter now. My plan is to drive it for ~5000 miles then pull the whole pan off, check for metal in it, replace the gaskets and call it a day.

As for the transmission, I am ordering a filter and once it arrives I will drop the tray, replace the filter top off the fluid and do the same ~5000 miles and repeat.

Hopefully, this will cure any immediate issues.

I do have another question though, How much transimission fluid does this thing hold? I drained about three quarts and replaced with new fluid, ~3 quarts, and it topped off....I thought these beasts held 10-12 quarts???? Are there multiple drain plugs or a trick to draining the entire system?

Thank you again,

Roger

(the old thread talking about the hand pump for adding in the new oil was a life saver...I picked one up soley on the basis of that post and had I not, I would have been S.O.L. on refilling)

 

[hubris]

One additional question to the others in the above post.

My plan is to drive to the LR until the Transfer case gives out completely, before replacing it. My understanding is that doing so will do no additional harm to the drive train. Anyone know if my understanding is correct or not?