I'm having a problem that I haven't been able to find and finally decided to ask on the forum guru's.

I've got a '93 D350 Ext cab Duallie tweaked to 250 RWHP (pump and injector mods by Dr. Performace, 3 1/2" exhaust, heavy exhaust valve springs, K&N air filter), 5 speed Getrag, 3.54 gears. Had the Trans rebuilt at 75k, and a clearance and bearing check (health check) at 100k, Diff rebuilt last November (broke a tooth on the pinion, ouch), truck just rolled to 136K original this weekend. I tow a 28' 5th wheel, about 12K lbs. I do have an 1/8" shim in the carrier bearing to "pre-load" the rubber (slips in between the rubber and the crossmember). This was recommended by a friend to help eliminate the hopping in the driveline when backing up my driveway (yes, it works quite well).

My problem is a "Ting, Ting, Ting" when pulling away from a stop. I hear it ting 2-4 times, then it goes away once I'm rolling. It's most obvious when pulling the trailer, but still there even running empty. It's been there for about 2 years, doesn't seem to be getting any worse, I've changed the U-joints, and the diff overhaul didn't make a difference. I'm thinking carrier bearing, but wanted to get some opinions before throwing more parts at it.

I'm planning a 5-6K mile trip this summer and want to make sure I don't leave important parts laying in the road someplace... I will probably be pulling the trans for another "health check" along with checking the clutch, and can plan to swap the carrier at the same time.

Thoughts??? (other than turning the stereo up a little louder.. )
Thanks,
TruckU

 

I'd look over the underside real good, checking all shields and gaurds. It sounds like one of them is loose and shaking a little on take off. It may even be a loose baffle in the muffler, that happened to my wifes S-10, drove her nuts, well, the rest of the way. Bang on the muffler with a rubber mallet.

 

I had a similar problem on a Ford I had. It took driving with someone in the bed to diagnose it. Turned out to be one of the leaf springs had shaken a shackle loose, causing it to jingle when I hit a bump. Have a buddy take a ride in the back to see if he can find it.

 

It's not a rattle, it will ting in reverse same thing as first (also in second, but not as noticable), and the harder I'm on the throttle the louder and more metallic is sounds... It's under the truck, behind the seat, louder when near a curb, and the gaurd at the gate at work keeps looking at me everytime I pull away, so must be louder outside the truck.

I've been under the truck (with it shut off!!) shaken the exhaust, checked mounts, etc, but have not looked at springs. It doesn't sound that far back, and is the same (other than the load variance mentioned above) whether I'm loaded, unloaded, overloads aired up or aired down....

Hope this helps

TruckU

 

How's the slip yoke on the driveshaft? Lubed it recently?

 

By the way you describe it, it sounds like you have something that stabilizes after the centrifugal force pins it down. Try to see what speed it stops at, then drive below that speed to see if you can locate it.

 

Thanks for the input, hadn't thought of the slipyoke, will lube it and see.

As for pinning it dow, it only happens under the intial load of gettinging moving. Makes it tough to find when you have to keep sarting and stopping...

 

If the lube doesn't work, try pulling the shim.

 

since u have an ext cab u probably have a 2 piece rear drive shaft...look under at your carrier bearing...its possible that the rubber is torn and the shaft is sitting on metal.....another option is driveshaft u-joints...my carrier bearing was busted for while before i actually looked under...it was howing for a couple months, then grinding, shaking, vibrating, rumbling....all kinds of noises...

 

I agree - I'd check the carrier bearing first, for either worn-out rubber or incorrect driveline angle.

 

Could be the carrier, need to crawl under. it makes the same sound on decell re-accell

 

far off and unlikley but ive heard it of it lol, couple times i know of, there was just a peice of weld inside the driveshaft when they welded it together caused some noise, but doesnt sound like it to be your case

 

still need to look into this, but right now the truck is DEAD. Lost the throttle shaft seal, and having some problems passing emissions (before the shaft seal went). Need to get it running again before I tear into anything else. I did check the driveline, and the center u-joint looks suspect, going to shoot everything full of greasse (one at a time) and see what happend.

Also, my slip yoke, behinde the carrier bearing, doesn't seem to have a grease fitting. It does have a rubber boot over the slipper portion. Any thoughts?