What do these numbers mean

[bubbz]

Hello. I have a 1979 CJ5 and today I heard a loud clunk when climbing a hill in four low. It sounded like the Transfer Case was jumping teeth, BAD in 4 low and not as bad in 4 hi. Every thing seems fine in 2 wheel drive. I noticed that I have the two top bolts loose/missing where the Transmission bolts to the bell housing which could maybe be part of the problem. not for sure. I have found that Im pretty sure I have a Dana 20 TC but the only numbers I found on the Transmission are E-CA-QU and 2503347 as best as I can make them out. I just got the jeep and know very little of the beast. Everything I have need in the past I have found here from searching.. Thanks for any help and/or advice.

 

[bubbz]

 

[BusaDave9]

I too have a '79 CJ5 .
Unless a PO has swapped it out, you have a Dana 20 TCase. You can make sure by looking at how the shift lever is attached. If it is a Dana 20 there is a tubular bar sticking out the front that has the shift lever attached to.

This picture above has a twin stick installed but the black tubular bar sticking out the front is OEM.

Okay, next issue is the noise. So it happens in 4WD high and low. The TCase uses completely different gears in high as opposed to low so I really don't think that's it. I think it's more likely a problem with the front drive shaft or front axle. Or could it be a bad tranny or TCase mount. That could cause metal to metal bumping. Diagnosing a noise problem over the Internet is hard.
Here's something to try: put wheel chocks and block your Jeep. Put your Transfer Case in neutral. Lock your hubs. Make sure your CJ can't roll by trying to push it. Crawl under it and grab the drive shaft. try to rotate it back and forth. If you have any free play see where it is coming from.

 

[Petescj]

I noticed that I have the two top bolts loose/missing where the Transmission bolts to the bell housing which could maybe be part of the problem. not for sure.

So it happens in 4WD high and low. The TCase uses completely different gears in high as opposed to low so I really don't think that's it. I think it's more likely a problem with the front drive shaft or front axle. Or could it be a bad tranny or t case mount.

Im going with the 2 highlighted areas. The missing/loose bolts are a definate issue when torque is applied. Depending on how long it was like that it can easily destroy a over 30 year old mount if they were never replaced.

 

[bubbz]

The bolts are my first order of business for sure.. Just wanted to add that early today I put it in 4 low but hubs were unlocked , as I have done to pull my boat from water with F150, and same popping sound happened.