I recently had my truck (1995 Bronco 5.0) in the shop to have some minor issues taken care of and asked the mechanic to see if he could figure out exactly what was causing my drivetrain clunk. My clunk comes in several variations - on initial shift into gear, either forward or reverse, if the engine RPMs are over 1000 it will sort of slam into gear. When moving from a stop at a light i get a two or three part clunk, depending on how fast I start off. I have taken the slip yoke apart, cleaned it, greased it, checked all the u-joints in the rear shaft, checked all the bolts. Nothing. So he looked at it for me, thinking it really just might be the u-joints. When I picked up the truck he told me he was almost certain it was in the transfer case and that it would probably need a rebuild, which he said might run about $350. Now, that's not a terrible price, but I figured I would post and get some questions answered. First, if I wanted to do this myself, what would it require and how difficult is it? Keep in mind I've never done anything too complicated, some brakes, water pumps, starters/alternators, some exhaust work. How much time would something like a t-case rebuild take? Second, has anyone else gotten a similar diagnosis? I would really like to kill this clunk once and for all because it's hell in traffic. It doesn't seem to really affect the driveability of the truck but it annoys the bejesus out of me and passengers. Should I just plunk down the $350?

 

I say invest the $350 or invest in a loud sound system.....or both
lol

 

i wouldn't waste your money on a new transfer case. i can almost guarantee you the problem lies in the driveshaft spline. if yours doesn't have a grease fitting then take it apart and grease it up.
i had the exact same problem with my 96 xlt. i posted about this a couple years ago. i believe it helped alot op people out.was a really long thread about it.

 

I had the same problem with my '95 EB - clunking that could not be traced to the normal slip yoke problem. I had a mechanic run through and check and lube the whole drive line, but it just kept on clunking. Decided I would just have to live with it. Then one day I had a problem with my speedometer, ABS light, and rough shifting. Pulled the codes and put in a new rear speedo sensor. The clunking stopped. No idea why, but there must be some electronic signal involved in some of the clunks. Problem is that it is starting to come back, but only sporadically, and not nearly as bad as before - and only on accelerating from a stop.

 

One thing seems like nobody does is change the oil in the transfer case, rearend,transmission and frontend.

 

Well, it's definitely not the splines in the driveshaft. I've taken that apart probably four times now and used four different kinds of grease to see if that would do it. Nothing. It's not the rearend, because I got hose last spring when a mechanic decided to replace my rear spider gears, thinking that was the problem. Not it. I just had the tranny fluid drained and changed while it was getting the brakes done. Also not it. U-joints were checked and are fine. So, it kind of narrows down to the t-case, and I don't see how fluid could cause the sort of noise and jarring I get when starting from a stop. If it was just a noise I wouldn't really mind, but it feels like the drivetrain "catches" and thuds twice or three times at low speeds. It's done the same thing for going on three years, so it's obviously fairly driveable as is, just annoying. So, anyone ever rebuilt a t-case?

 

If you drain the transfer case oil into a clean container you may be be able to see any metal particles present if this is the problem area. The oil doesn't wear out but it gets dirty and draining it can give you a good indication of its internal condition.

 

One more thing I just remembered. A few years ago I pulled the rear cover off one of my rear ends to drain the oil and look at the gears. I found three ring gear bolts lying at the bottom of the case. If the ring gear had picked them up and carried them over to the pinion it would have been disaster.

 

i doubt if the transfer case needs an overhaul, though it's possible.

i'd take a real hard look at the cardan joint knuckle. if they are worn in the slightest bit, you'll get that "in to gear" clunk. the cardan joint knuckle costs about $70.00

if you've got any miles on the Bronc, i'd think about replacing it. it's a simple job and should take less than an hour. the hard part is just dropping the rear drive shaft down

good luck.

ambrose

 

I just did a post on the double cardan rebuild a couple of days ago. I listed the Spicer P/N in the post. The centering ball was $19 and the slinger(if you need it) was only $6. I too was having that clunk that you are talking about. I think the real clunk was the u-joints in the double cardan. They looked great while on the truck, but when I dropped the drive shaft and took everything apart I found that one of the caps was cracked, no grease and the needle bearing were gone. A different cap was full of dust(what used to be the needle bearings). It's worth pulling apart.

I also doubt that the tranfer case needs to be rebuilt. It's a pretty stout TC and how many miles have you really put on the TC itself? Great suggestion earlier on draining to see if there are any metal shavings.

 

I'd like to hear more about this cardan joint thing. It's dark right now so I can't get out and look under the truck, but where on the driveshaft is this, up by the t-case? I could have sworn the only joints on there were the u-joints, two by the t-case and one by the rear axle. Does it have something to do with the two-joint setup near the t-case? I guess I just need some more info, as this sounds more like something I'd be willing to do myself, although when I looked at taking off the rear shaft I remember seeing the setup of the bolts for the flange by the t-case and it looked like it would be might amusing to figure how to get a wrench in there. Thanks guys.

 

Yes, the 2 U-joints with the centering ball between them inside the large collar are collectively known as a "double cardan joint". It's often incorrectly called a CV joint, but it's not. The only function of a DC is to split the total angle between 2 u-joints so the driveshaft can flex further without binding. A DC does NOTHING for the variations in angular velocity that a Constant Velocity (CV) joint solves.

 

Here is a detailed write-up. Just make sure that you do a search for "double cardan rebuild" that I just posted a week or two ago to see the NEW Part numbers from Spicer.

 

Hey lookin.....Excellent explanation

 

Thanks, but I have to say that is Keith Lawyers Superford page that has the detailed write-up. Yes, he does have an excellent explanation. I also used that Harbor Freight press and that made things sooooo much easier.