Whine while decelerating with light/no load

First id like to say sorry if this has been touched on, I did google search/read some threads first but haven't found a definitive answer to this exact issue.

My father has a 2008 Tacoma 4x4 5spd manual. Years ago his leafs broke and it wasn't covered under recall so we purchased a set that claimed to lift the truck .5", This ended up in reality being 2.5" of lift so we added a leveling kit to the front as well.

Instantly the truck developed a whining noise when coasting weather in neutral or in gear, however, in gear it only happens when there is no drag (for instance, say 40mph in 5th gear where the transmission is not actually slowing the vehicle). I figured on it being the driveshaft so I did grease it and this didn't change anything.

This noise has been going on for about 10 years (100,000 miles) haha. So he is now at 181k and I am replacing the original clutch for him and figured maybe we could tackle this too if anyone has had the same issue?

The noise sounds like straight cut gears in a racecar if that helps.

 

does the noise change when you push in the clutch while coasting?

 

It doesn’t. The only time its not there is when there is a load on the drivetrain

 

I believe my truck does this same thing. I have about 2.5 inch lift and any time over 55 when I let off the gas or coast, doesn't matter if I'm in gear or neutral I hear what sounds like wind noise or a slight grinding.

What I've found on this site is that it has to do with the slip joint on the driveshaft. When you lift the truck, the slip joints gets a little over extended. I've read driveshaft spacers can help but it's no gurantee.

I think the general consensus is that it doesn't really hurt anything and most guys have been driving like that for years with no issues.

 

yeah, that sounds like it. If I am remembering correctly I think the noise used to be around 50+MPH when we first did the lift. now it seems to be a bit less like 30+. I am starting on the clutch this afternoon, while down there I will try to look around and see if anything obvious sticks out. I have read about removing the rear driveshaft and driving in 4H to see if it goes away...Although now would be the perfect time with the driveshaft off anyway for the clutch, I don't feel comfortable testing the brand new clutch with the truck altered like that so maybe next week I can do that test.

 

Since it's 4wd, remove the rear driveshaft, put the truck in 4HI and go for a drive. That will definitively rule out whether or not it's the driveshaft.

 

my 15 auto has a slight rear diff whine around 60-70. Doesn't do it on acceleration or deacceleration. almost seems like it happens when there is zero load. 3rd gen trucks have a big problem with this. Mine has done it since I bought it with 56k on it. 20k miles later the sounds has stayed the same.

 

Thanks, I will try this after the new clutch is in.

 

I wondered if this was my issue too just seemed to coincidental that it happened right after the lift