Dana 18 and locked rear wheels

I was running a few errands in the jeep after work today when I encountered a small problem. I was cruzing down the road about 50-55 mph when I thought I heard a funny tick tick kinda noise. I figured I should pull over and give everything a once over. As I slowed to about 25-30 the rear wheels locked up and I came to a tire squealing stop! The rear wheels were locked up solid. I was now stuck in the middle of a lane on the highway so i put the transmission in neutral and jumped out to see if it would role. No luck, so i ran around to the passenger side and tried to get the transfer case to shift from 2 HI to N. After much rocking and reefing on the shifter, I was able to get it into neutral and roll easily out of traffic. Once on the side of the road, I gave the underside a look. Finding nothing wrong underneath, I shifted the transfer case back into 2 HI and fired the jeep back up. I drove forward a couple feet and then backed up a couple feet and everything seemed fine. Hoping that I could make it to a friends house about a mile up the road I put it in 1st and let the clutch out. Everything went good for about 20 ft and then the rear wheels locked up again skidding to a halt.
I decided to make the call and wait for a trailer. Buddy showed up with a trailer and no come a long, winch, ect.... so only way to load was driving. We backed the trailer all the way up to the jeep and after horsing the shifter into neutral and then back to 2 HI, I started the jeep and crawled on the trailer with the rear wheels locking and unlocking a couple times.
The transfer case is freshly rebuilt with about 200 mi on it.
Of course Ill be taking it back to the shop that rebuilt it, but do you guys have any ideas as to the cause of my problem? I just want to be well educated before I take it back.
Kyle

 

Is the engine stalling when this is happening?

 

I know that it seems a little crazy, but I don't remember if the engine stalled when I was on the highway. You know the oh sh.... better get this off the road before I make the news feeling. When I was on the side of the highway, as soon as I felt the clunk and the lock up start my natural reaction was to push in the clutch. When I was slowly driving onto the trailer, the lock and unlock didn't seem to effect the engine.

 

Yeah I know the feeling....When you are in survival mode all the little details don't really matter. Im glad you're ok... I guess I would start by jacking up the jeep and spinning things by hand. Any chance it could be a broken ring gear in the diff?

 

I don't think that it is in the rear diff because it rolled easily once I got the transfer case into neutral. I will be jacking it up tomorrow. So to really make things frustrating, I just went out and unloaded the jeep to see if the engine was affected by the lock up and skid. Well I cant get it to do it now!... I couldn't even move the jeep 20' earlier and we barley got it onto the trailer. I figured id have to tow it into the shop with the tractor, but I was able to back it off the trailer and drive all around, I was even gritting my teeth and bracing myself for the rear wheel lockup!!! Now I'm trying to convince myself that Im not crazy.... and it was necessary to get towed home today.

 

Sounds like fun, I think I've broken about anything on a Jeep a person could, or a friend has. It does sound like something is going on in the transfer case. Broken shifter fork? Errant set screw? Let us know what happened.

 

Hi,

How loud was your "tick tick" sound... this is scary to me because since I own the Jeep I keep hearing a faint tick tick sound I think is coming from the tranny or transfer case or clutch. I say that because it does not seem to be affected by the engine speed. Its not loud so I don't really hear it at 50 mph although its probably still there. I have driven the Jeep over 3,000 miles since I got it with no change... so I kind shelf the noise as "normal" or may be a broken clutch spring? - may be I shouldn't?

 

About the only thing I can think of that would make a D18 respond like that is a broken tooth getting hung up between gears-and maybe the reason for the "ticks". I don't think there is anyway a loose shift fork could partially engage low range at speed. I wish you luck. Someone would probably need to confiscate my guns when visiting the rebuilder and why I really like doing that stuff myself.

 

It was just a subtle tick tick, I actually thought it was exhaust related.

 

I'd drop the pan on the transfer case and take a look; be careful, the pan could be holding 25 lbs of debris.....
I had my original transfer case lock up on me just like that....at Pismo beach.
One of the caged intermediate rollers came apart and then distributed its self thru the gears.

 

Holy cow!......Norcal69...that's scary!....glad you're OK!

 

Thanks for all of the ideas guys! I have kind of a wierd relationship with the shop that built the t case, its a long story, but I will be pulling the transfer case out myself and taking it in there. I'll catch the gear oil and run it through a paint strainer to catch any metal particles.
I have been thinking about pulling the saginaw 4 speed out and installing a T18 from Herm. Now would be the best time to do it and his would be a direct bolt in place of my saginaw with the 1 1/8" 10 spline input.

For those who have the advanced adapters tapered roller bearing intermediate shaft; How much quieter is it? Does the transfer case run cooler? Is it worth the added cost?

 

A lot more quite but perhaps more important, they last way longer. I'm sure they also reduce the temp a bit but somewhat insignificant. Worth the cost? IMO, absolutely.

 

I had a very similar thing happen to me. Drove the JEEP to a meeting spot for a club trail ride. As I entered the lot, the JEEP suddenly stopped after a horrendous thud. Wouldn't move forward or back. Finally got it to go again and it did it again in about 20'. This happened 3 or 4 times before I got the JEEP into a parking spot and hitched a ride for the event. Towed home about 30 miles with a chain, in the dark, transfer and trans in N. When I dropped the pan on the D18, I found 4 teeth had come off of the intermediate (?) gear. Might have been the sliding gear. It's been like 25 years ago, now. Mine gave no warning. Of course, the thing was so loud I wouldn't have heard any early warning noises anyway.

 

Another vote for broken gear teeth in the t-case.

Pull the round cover off the back and pull the pan off the bottom to look.

Glad to hear you're ok.

 

Drained the case last night, Tons of brass in the bottom of the pan. The magnetic drain plug has alot of metal shavings stuck to it. I'm going to try to get it pulled out tonight. I removed the pto cover and I can see some small chips on the rear intermediate gear. Am I correct thinking that the brass is from the intermediate gear thrust bearings?

 

I'd say that you now have some good indicators of your actual problem. And this TC was just rebuilt? I'd have a little come-to-Jesus meeting with the rebuilder.

 

Brass?..........a little on the thrust washers and a bunch in the Syncro's...