Jeep Guys, need help here.

[moparguy]

Jeep is a 79 CJ5, 304, 3 speed in good condition. I need help is diagnosing the popping binding noise from (I think) the transfer case. Only happens in 4wheel drive, low and hi range.



It sounds almost like the front drive shaft rear u-joint is hitting something, or possibility a gear or chain binding and popping. Again only when transfer case is in 4wh. drive mode, front hubs locked in or not, no difference.



All U-joints and slip joint yolks appear good and are freshly lubed, not that they couldn't be at fault since I haven't pulled and really checked yet.



Only happens when I apply moderate to heavy throttle in 1st or 2nd gear, high torque situations. It sounds like if I did it for more than a couple of seconds something is gonna break. No odd noise in hi gear 4hi cruse mode or any other gear in a no load situation.



My fear is I'm gonna need to pull the transfer case, just don't want to go there if not the problem.



Any help is appricated.



Thanks,



RJR

 

[Crazy Horse]

I don't know if you can pinpiont an area of the vehicle you are hearing it. . . can you feel it in the floor? steering???

Might check motor/trans mounts = torsional vibe??? or check slip splines on both drive shafts good.

 

[Crazy Horse]

I vote for front slip spline.

 

[moparguy]

New Info and what I know; motor mounts and U-Joints and slip joints are all good. It's a Dana 20. I've just discovered that there are 2 shifter positions for 4L, one is all the way back or down, depending on your take. The other is 1 notch below neutral in the transfer case. I guess I've always used the 1st. 4L position.



I get the death noise in the second or futherest down 4L position. The first or nearest to neutral position, NO odd noises.



Still have the Death Noise in 4H.



I'm a little encourged that it's not a pull transfer case an get into a birdsnest of issues. However not sure at this point.

 

[PBJ2500CTD]

You should have only 4 positions: 2H - 4H - N - 4L. Any other positions mean you are not fully engaged into your selection. Without hearing the noise there are two conditions that come to mind - 1. Front cardan joint (the double u-joint) at the transfer case on the front driveline, and 2. A busted tooth on one of the gears in the transfer case. I can't remember if the '79 had a chain or gear drive coupling. I've had so many different 4x's over the years.
Best check would be to put it up on a rack where all 4 wheels can turn and run through all of the transfer case positions while observing from underneath. Don't leave out checking the hubs (common problem if not serviced on a regular basis) and the outer u-joints.

 

[Dl5treez]

Dana 20 is all gear. No chains.

 

[Schumacher]

The dana 20 is a pretty stout t-case and can handle a fair amount power. I would first pull the front diff. cover and check for broken ring and pinion teeth. IThe dana 30 r&p will brake normally before the t-case.

 

[moparguy]

Schumacher, thanks for the suggestion. However I did have the front diff. cover off last Saturday while changing the diff lube. Everything looked good.



Also, no noise when the proper 4L position is engaged. The Death Gear noise is just in 4H.

 

[Schumacher]

Moparguy, I know you said it was a 3sp. I assume it's a manual and not an auto 3sp. If it is an auto the rear diff. will be offset and the t-case is a quadra-trac chain drive. The quad is known for popping under torque as an old chain stretches and skips teeth. just a little more info. Good luck in running the probl. down.

 

[moparguy]

Good to know. It is a T150 manual 3 speed. Based on what I've learned over the past coupla of days it looks like the only option is to pull the TC and see what's amiss inside. Based on my recent Internet smarts the D20 is pretty simple and stout, guess I'll know more when I have time to do the R&R&R. (remove rebuilt reinstall)



Ronnie

 

[moparguy]

GOOD FOR ME. Made it home a day early, got both ends of the CJ up on stands, after much coaching the wife (who is likely the most helpful wife on the planet,,, yeah she's reading over my shoulder:-laf) was able to hold the brake while giving enough gas to torque things up a bit, causing the Death noise.



I get under the Jeep and finally figured out that on the rear of the front driveshaft, one of the rear u-joint clamp nuts is barely hitting the rear motor mount bracket when things get in a bind.



Drop the skid plate and find the two rear mount bracket bolts are out of the transmission. Mount was bolted to the skid plate, but not the transmission allowing things to make noisy contact.



Thanks for the help and support.



RJR

 

[Crazy Horse]

Might check motor/trans mounts. . .

Glad you found it.