T-90 or D-18 3rd Gear Whine

Hello,

This is my first question for the group. My "65" has the usual T-90, single lever D-18. The question I have is whether I have a transmission problem or a t-case problem. Shifting into 2nd gear is slight crunch, shifting into third is also a slight crunch or with patience no crunch.

But only when in 3rd is there god-awful whine. Backing off the gas pedal and relieving stress or torque makes it tolerable but as soon as you put a little torque on it the whine makes my head hurt.

Should I be looking at the transmission or transfer case?

 

Put you tc case in neutral and shift thru the gears like you was driving it, no noise tc noise tranny

 

Jason's reply is correct for the trying to figure out which is making the noise. I have seen the rear output bearing fail in the T-90, but it will only make the noise when you are putting a heavy load on it, 3rd gear. Sometimes it can be hard to hear the noise with the t-case in neutral. Grinding in 2nd and 3rd are a definate indication that the syncros are worn out. When replacing the syncros also replace the syncro hub. These will also wear out.

 

"Shifting into 2nd gear is slight crunch, shifting into third is also a slight crunch or with patience no crunch."......Sounds like you do have some issues with the tranny.

The noise if it's coming from your tc could be your intermediate shaft wore as well

 

Keep in mind that the D18 is not known for being quiet- mine sings at 100dB+ at 55MPH. It always has.

 

Probably I should have described it as a gear whine. Best I can say is that it sounds like the nashing of gears that don't quite mesh and it's only in 3rd. Otherwise it's reasonably quite. First time I drove it I wanted to move the gear lever around to see if it really is in gear.

 

Yes. Dana marketed the D20 as a "silent" transfer case... silent in comparison to the D18.

A worn D18 is really, really noisy though.

 

After testing the suggestions of putting the t-case in neutral and running through all the gears and releasing the clutch, there is no difference and is actually fairly quiet. I can only recreate the noise when putting some gas to it, only in third gear. I can quiet it by backing off the gas or if coasting when there is no real torque on the gear.

 

Mine was doing the same thing and it was the intermediate shaft and bearings in the transfer case. I would get a headache from driving because it was so loud. It's an easy fix that can be done in about an hour with the transfer case still in the Jeep. You just have to drop the transfer case pan and remove a bolt or two holding the intermediate shaft in. It really makes a difference. It made my Jeep actually pleasant to ride in. I got my rebuild kit from Novak. As for the tranny, it sounds like synchros could be shot if it grinds. Check your fluid level and make sure you're using GL4. Synchros aren't hard to replace and the T90 is simple to rebuild.

 

I also have the Warn OD. Someone apparently did something, a small part of the floor was hacked for the OD lever located next to the transmission lever. Would that mean that a different transfer case was swapped or that OD was added?