ZF-6 noise on the freeway
Thread Starter
Instructor
Joined: Dec 2002
Posts: 116
Likes: 1
From: San Jose CA
ZF-6 noise on the freeway
I just recently switched to a 4.11 rear end, and I think it may have exposed a bearing going bad in my transmission.
A warbling whine starts somewhere between 65mph and 70mph. Seems to be coming from the rear of the tranny, not the rear end. It's pitch is directly connected to road speed (not engine speed). It tends to quiet down or even go away under acceleration or deceleration. It gets quite loud at cruise.
It may actually be going away on its own... it seems like the symptoms have gotten less as the new rear end has gotten more miles on it. But I dunno. It probably shouldn't have provoked a noise in the first place, so it's an indication that something is wrong.
I'm not a mechanic, but it sounds like a bearing going out to me. It's sound is similar to when the bearings are going out on a computer power supply fan.
Are we talking about transmission rebuild time here? ($$$$!!!!) The car has 50k miles on it. Could this reasonably be a case where just the bearings on the output shaft could be replaced or something? Or is this maybe not a big deal and the sound really could go away completely... and I just need to get the miles on the rear end and do its service at 800-900 miles to change the rear end fluid after the breakin.
This noise is really annoying and loud enough that I can't squelch it with my stereo... in large part because of the pitch it's at.
Hoping for some good advice here. My wallet is scared.
- Skant
A warbling whine starts somewhere between 65mph and 70mph. Seems to be coming from the rear of the tranny, not the rear end. It's pitch is directly connected to road speed (not engine speed). It tends to quiet down or even go away under acceleration or deceleration. It gets quite loud at cruise.
It may actually be going away on its own... it seems like the symptoms have gotten less as the new rear end has gotten more miles on it. But I dunno. It probably shouldn't have provoked a noise in the first place, so it's an indication that something is wrong.
I'm not a mechanic, but it sounds like a bearing going out to me. It's sound is similar to when the bearings are going out on a computer power supply fan.
Are we talking about transmission rebuild time here? ($$$$!!!!) The car has 50k miles on it. Could this reasonably be a case where just the bearings on the output shaft could be replaced or something? Or is this maybe not a big deal and the sound really could go away completely... and I just need to get the miles on the rear end and do its service at 800-900 miles to change the rear end fluid after the breakin.
This noise is really annoying and loud enough that I can't squelch it with my stereo... in large part because of the pitch it's at.
Hoping for some good advice here. My wallet is scared.
- Skant
Safety Car
Joined: Apr 1999
Posts: 4,623
Likes: 2
From: Ohio
Re: ZF-6 noise on the freeway (Skant)
Don't jump to any conclusions. A ZF is a TANK. Now, that doesn't mean you can't screw it up. When your rear gears were replaced, did you (or your mechanic) take the time to PROPERLY align everything before bolting the "C" channel back in place? Did anyone use a torque wrench? You MUST be carefull not to overtighten the front bolts, as you will TRASH the tailshaft bearing on the trans!
