Engine/Transmission (1998.5 - 2002) Intermittant clunk in drivtrain

[TSRAM]

I recently broke the output shaft on my new transmission acting stupid. Thanks to Bill K. for the fast shipping and great price on a OEM shaft. No I didn't get the Billet shaft because "I'll never have the power or ignorance to break one".

After replacing the shaft I have noticed that upon braking almost when I get to a complete stop, I have a slight "bump" toward the rear in the drivetrain. It dosn't happen every time but maybe 25% of the time. About as often there is the same thump upon accelerating slowly from the rear. I haven't pulled the diff. cover yet but tooth or two off the ring or pinion gear is my first guess. The u-joint looked good upon removing two weeks ago, and the transfer case seems to be working fine.

Any guesses guys?

BTW, I didn't remove the transmission. Took the OD section off and took to a local trans. shop to install new output shaft.

 

[maint.man]

I had the exact same problem , it felt like slack in the ring and pinion. This may sound dumb , but mine stopped , when I adjusted the rear brakes. (excessive clearance between pad and drum) The only thing that I could figure , was that with the space in between the two I was getting delayed brake force and release in the rear, Hope it works for you

MM

 

[csutton7]

it could be coming from the front control arm bushings --check them out--in the rear--did you double check all bolts that got removed and then replaced from doing the output shaft replacement--chris

 

[JPLB22]

I am having the same problem upon braking. At first I thought it was coming from the front driver side but upon closer scrutiny I figured it to be coming from under center of truck. I went ahead and tried tightening the trailing/control arm bolts, but they were all in spec. I did the shake test of the front and rear drive line, not much play at all in either. I did notice a little up and down play in the T-case.



How much up and down play is allowed for T-case ??



Also I realized that when I was feeling the clunk most often I was around half a tank of fuel ( sloshing ). As I got closer to empty ( I fill up at a 1/4 tank ) it seemed to happen less. Then last night I filled up and have driven about 38 miles since and have not heard it once. Guess I will have to see if the clunk returns again around half tank.



Jeff

 

[TSRAM]

OK guy's it's been awhile since I posted this topic. I went out tonite and checked the rear diff gears. No missing teeth or abnormal wear. WHEW !! There does seem to be some backlash between the ring and pinion gears however. At least maybe more than I remember, but not too bad at all. The rear brakes seemed to be a little tight as I had trouble getting the drums off so I loosened them up a dab. I must've turned them up a little too much last time.

Anyone else found out anything new. I read where at least one more of you had the same prob. happening.

I haven't hammered the truck since the quirk after the output shaft and it's driving me NUTS!!

 

[WadePatton]

I'd check the yoke. A local had his back off and WHAM WHAM--a lot of damage.



Backlash is necessary--but there is a limit.

 

[Ram666]

try puttting some silicone type grease on your output shaft splines. this seams to be a common problem on other types of trucks we see in our shop. the problem is called spline bind up try this and see!!! this usually happens after we install rebuilt transmission... Chris.

 

[TSRAM]

Ram666, I haven't tried to lube the splines yet to be honest. I am beginning to wonder if maybe something in the transfer case could be damaged. The transmission shifts fine but I swear it feels like a gear skipping teeth in the rear part of the driveline. I've never seen a breakdown of the transfer case, much less tore into one so I can't be sure.

The problem only occurs around 10mph or so. Can't duplicate the "bump" after the initial one rolling on the go pedal.

 

[Jim's slt]

Iam getting the same scenario, I was looking thru the tsb's. I'm

going to have to ck fuel level next time it happens.

Customers may hear a thump/bump sound that occurs 1-3 seconds after the vehicle comes to a complete stop. In some cases, the thump/bump sound may be transmitted through the floor of the vehicle allowing the customer to feel the thump/bump in the floor pan of the vehicle. The sound will only occur when the fuel level of the vehicle is between ½ and 7/8 tank of fuel.



Since the fuel level of the vehicle must be between ½ to 7/8 full, the condition may be difficult to diagnose. The repair involves replacing the fuel tank

 

[TSRAM]

On mine the truck itself gives a bump in the drive train. This has happened over the course of the last month and all kinds of weather or fuel condition. The rear gears look good. I can push the yoke at the transfer case and get some slight movement not coming from the u-joint, but from the transfer case shaft or the yoke itself.

I have read several other members have broken output shafts and are more informed than I am I'm sure. The output shaft broke while doing a 4x4 launch with about 20lbs boost... snap.

Is it possible that the transfer case chain is loose now, the anti-slip carrier is boogered, or could the local installer screw up with the R&R of the output shaft. I removed the OD section and took to him for the R&R of the output shaft and watched it all.

I might would think of the rear brakes binding up then snapping loose all at once, but I haven't found that either.

I will this weekend put the rear on jacks and run the truck to see if there is any binding going on. All else fails I'll call Bill K. but I do hate to bug a busy man with problems that weren't his fault to begin with.

 

[AGibson]

drive train thump

I have had the same problem with my 98. 5 (294K miles). I rebuilt my own transmission and know it is right. I replaced my front drive shaft which was marginal. I replaced u-joint on the rear drive shaft. I went to replace pinion bearing/seals in the rear differential but they were still good. I did noticed extensive backlash in my transfer case. After asking a lot of questions I will open up the case and check the chain and sprockets soon. I had a lot of bikes that had stretched chains and worn sprockets but they made an oscillating vibration/noise. I will post my solution it I ever find the cause.

Alan

 

[TSRAM]

I called Bill K. and asked his opinion. H eseems to think that the famous snap ring in the transfer case is broken. Gonna open it up tomorrow to have a look.