T15 noise

So I finally got out and drove the jeep around today and the day before and I noticed a noise coming from the transmission. The noise is a very high pitch wine/vibration that can be felt in the shifter and down on the T-case stick. The wine is in all gears and gets louder and more rapid with increasing rpm's. I have noticed the noise since I have owned the jeep but i never thought much of it untill reading some related threads more recently. The trans in the jeep was replaced witha used and presumably rebuilt one in 92 and only has about 500 miles on it since... Question 1 this isnt normal right? everyone else has a "quiet" trans with no high pitch noise? Question 2 should I rebuild the T-15 or take this opertunity to replace it with a T-18? any one know a time/pice comparison for the two options?
Thanks again everyone, maybe someday I will be doing more jeep driving than fixing and asking questions... but not today... or tomorrow either...

Jake

 

Does it shift smoothly? Proper amount and right type of oil? These transmissions aren't exactly quiet, but mine doesn't whine as you describe.

 

Yeah it shifts fine and doesn't pop out of any gears... It is full of 90 wt gear lube... What kind of noise does a typical t15 make? Thanks for the help.

 

Start you engine and put the transfer case in neutral. With the jeep sitting still, shift the T-15 through all gears and see if you still have the whine and vibration.

 

Does it make the noise when it isn't under load? If it doesn't it could be a thrust bearing in the rear diff. telescoping the noise up the driveline into the tranny. Try disconnecting the rear driveline and drive it around in front wheel drive, if the noise is gone then you found the problem.

 

I put the transfer case in neutral like suggested and drove through all gears. The noise is not there when the t case is in neutral. (Or at least much more quiet) is there anything that can be told from that? I should have more time to work on it later this week so I can disconect the rear driveshaft and see if that makes a difference. Any thing else I should try? Thanks, jake

 

That says the noise could be coming from the transfer case, rear driveshaft, or rear axle assembly.


Sent from my iPhone

 

How then do I go about eliminating each of those as possibilities? Remove the tea driveline first drive in from wheel only if noise is gone it is not the t case but could be drive line or behind? Do I just have to start replacing parts to see what works? Or are there visible worn parts that I can look for?

 

Remove the rear drive line as you say above and check the U joints and also look for play in output shaft at parking brake assy. Check yoke at rear diff for play. Drive jeep and if there are no noises or vibrations then I would have to pull rear cover on rear diff and take a look see.

 

Got some more time to work on the jeep today. Disconnected the rear drive shaft and took it for a spin in 4 hi. Noise is still there... If my brain works right that means that the noise is coming from my transfer case... Correct? I pulled the plug on the t case to find oil that looked much like my morning cup of coffee but much thicker... (It's a dark tan color) I had this type of oil in the trany when I first got it so I drained it and replaced it with new clean oil. I thought at the time that the trany and tcase shared oil... I must had been wrong. Does this coloration of oil mean anything? Should I procceed and pull the tcase? Thanks again.
Jake

 

There should be 90w gear lube not oil in there. Real thick and smelly. I would dump it all and put new in, but it will not fix damage already done. Might make it quieter. The tranny and transfer share oil so do both at the same time.

edit.. Just read again and saw that you do have gear lube in there. Never mind.

You could try Lucas gear treatment. Really thick like 140w and can be added to all oils. I used it in a rear end on my atv when it was getting noisy and it worked.

 

I'd drain em, pull em, and inspect the insides.

 

I concur with Blue, I would start with the transfer case and look for abnormalities, if everything looks good there, only then would I drop the tranny.

 

What kind of abnormalities? i have never seen the inside of a t-case so I am not sure what to look for as far as damage goes... I am sure i could tell if something was actually broken... is there something else to look for?

 

Tooth damage, tempered metal (meaning it got to hot and expanded), gears not properly engaging when manipulating the transfer case shifter into proper positions and bearing decay which causes slop and improper alignment . You can YouTube "Dana 20" and get all sorts of videos to see inside a Dana 20. Its very simple design if something wrong you should be able to pick it out.

 

You could also tear into your other Dana 20 you have which has been sitting out for a few years. Get some practice, a good look of the inside and compare and contrast if and when you tear into your Dana 20. Heck you may even be able to use it as a part donor.

 

I was thinking of doing the same thing. Thanks for the advice. I will update once I find enough time to do the work...

 

So I found a couple of spare minutes today and pulled the bottom cover off the t-case... From what I can see all of the gears are solid with no broken or badly worn teeth. There isn't any slop exept for on the piece furthest to the passenger side which moves with the shifter. It has about a 1/6 of slop forward and back but does not slop side to side. Here are some pics of what I could see. Do you guys see something that maybe I am missing? The second image shows the only wear that I can find...

 

By coffee I figured you meant black coffee. That looks like coffee with creamer.

You injested a fair amount of water into there at some point. Water is not a good lubricant.

I would try to clean all traces of water out (I've been told running diesel in a gearbox for a min. or so w/ driveshafts disconnected will do a good job but I've never tried it personally) and refill w/ proper lube.You might find the noise will then be gone but there's a decent chance the damage has already been done if its been like that for a while.

 

I would not chance any thin stuff like diesel. I'd just drive it with the new oil and change it again. Gallon bottle from Walmart - remove the top and pour it in, and add some to the transfer case with a pump. The transmission and transfer case share oil.