Its likely gear rollover noise. Some are not bad , some are loud as hell.
New Clutch Doesn't Work *NEW ISSUE*
- Thread starter crash-harris
- Start date
hacked89
Full Access Member
Yep sounds like gear rollover. How the OP is describing it aligns with gear rollover as well.
crash-harris
Breaker! Breaker!
That's so strange. At idle, you can hear it louder than anything from a distance away from the truck, but the crew cab with the same clutch kit is quiet. Perhaps the jars in this one aren't as worn? Both transmissions were rebuilt before I bought the trucks, but the ZF5 in the crew cab has never been able to downshift to 2nd at any speed without a crunch, and this one in Thumper has been the smoothest shifter I've owned.
I really don't think it's rollover noise, that only happens lugging it in low rpm when the gears mesh. If it's idling in neutral you shouldn't hear much if any noise since there is no strain on the gears in the trans to have the noise echo through. My quad cab has some pretty rough rollover noise with the luk smf kit I put in it, anything under 1200 rpm in first or second gear especially on a hill sounds like the trans is going to explode. If you listen to Crash's video he posted, the noise is happening in neutral. At most on mine, I'll get a quick "chatter" if the engine rpm gets effected by the ac condenser or power steering pump at idle in neutral but nothing like what he's hearing.
I had an old zf5 on another idi that the input shaft had side to side play in that made more noise at neutral with the clutch out because it didn't have any strain on it holding it to a side from engine torque, thought it was a bad dmf but turned to have nothing to do with it. You mentioned seeing the fork moving with the noise.. just a thought. Might be able to wiggle things around with the truck off through the inspection plate and see if you can feel any play, not sure how tight things are when it's all bolted together for checking input shaft play.
I had an old zf5 on another idi that the input shaft had side to side play in that made more noise at neutral with the clutch out because it didn't have any strain on it holding it to a side from engine torque, thought it was a bad dmf but turned to have nothing to do with it. You mentioned seeing the fork moving with the noise.. just a thought. Might be able to wiggle things around with the truck off through the inspection plate and see if you can feel any play, not sure how tight things are when it's all bolted together for checking input shaft play.
crash-harris
Breaker! Breaker!
My crew cab has much more fork wobble/vibration than this one, and that was with a brand new fork. I thought gear rollover could be in neutral too? There are still gears meshing in neutral. I actually get less grown if lugging this truck than the crew cab, but I've attributed that to this truck having 2 less doors. Rollover would make sense for the fact that it doesn't do it at idle and in neutral while the truck is rolling over 15 mph, but it sure is loud when stopped.
hacked89
Full Access Member
Gear rollover is in neutral as well.
mf7lakes
Full Access Member
I thought rattle with a SMF clutch at idle was normal ??? In fact, think I read that on this forum.
crash-harris
Breaker! Breaker!
Some is, yes. I was just alarmed at how loud this one is. I'm going to attribute it to the transition internals just being in so much better shape than the ZF5 in the crew cab.
Both trucks are running N/A 7.3L blocks, but this one has a wastegated sidewinder on it. Even with it's sticky valvetrain and probably hourglassed valve stem guides (intake thumping and I've heard a rare chuff in the winters), the crew cab block has less blowby overall than this one.
