Why are the military Jeeps

Deadguy · Post by **Deadguy** » Thu Oct 17, 2013 8:41 pm

so loud? I had a CJ5, and a CJ7, the first had the same T90 transmission, the second started with it before it upgraded to a T18, and I don't remember either being anywhere near as loud. I always had Dana 20 transfer cases in the CJs, and the emergency brake wasn't that military driveshaft version that rattles. But that I've gotten used to, it's the gear whine I'm talking about.

Post by **wesk** » Thu Oct 17, 2013 11:13 pm

If you leave the interiors of all the early CJ's & M series that came with d-18s bare metal then what you hear is what you get. You found the answer all by yourself. The D20 has a better gear set and bearing set-up. If you compare the d-18 jeeps to the d-20 and newer jeeps you are comparing apples to oranges.

Most late CJ's, especially with the AMC takeover had smoother running gearboxes and often more insulation and carpet/mats to deaden the sound a bit.

My 42 GPW, 50 CJ3A, 52 M38A1 and 60 CJ3B all howled exactly the same.

Deadguy · Post by **Deadguy** » Thu Oct 17, 2013 11:17 pm

So, would you say the Dana 18 is the source of most of the noise? I've heard it's actually a pretty strong gearbox, noise withstanding.

Post by **wesk** » Fri Oct 18, 2013 12:32 am

Spur gears and no roller bearing. You can but the bearing kit from Novak I believe to get rid of some of the noise.

Deadguy · Post by **Deadguy** » Fri Oct 18, 2013 1:04 am

I did some reading up on the Dana 18, and was told that the gear whine is the result of wear on the intermediate gear and thrust washers. Even slight wear. I bought my Dana 18 as a rebuild from Novak, yet it has always had that noise.

Post by **wesk** » Fri Oct 18, 2013 8:14 am

Read more and you will find I have already given you the answer why the D18 is noisy even when it was new.

Deadguy · Post by **Deadguy** » Fri Oct 18, 2013 11:46 am

I read that, and I believe you, you're the expert. The thing that threw me off, is most people are talking like the transfer case isn't really that noisy until it gets some wear, even slight wear, and the roller bearings start to wobble on the intermediate shaft. They make it sound like "once it's making noise, it's on it's way out". Others say it makes noise, and replacing the intermediate shaft with one that uses tapered bearing only slightly reduces the noise. Not only that, but you have to adjust the new one every few thousand miles. That sounds like too much work for too little result.

Post by **wesk** » Fri Oct 18, 2013 7:21 pm

You have to weed out the BS from all those BS reports. Just apply what you already know to the BS you are reading. How often do you have to adjust the wheel bearings on the jeep? Why would you have to adjust the new tapered roller bearing in the transfer more often than that? Sounds like a dumb question right. That 's the problem with half the hype printed on the internet.