When the old guys say rear end clunk is normal - don't listen

[PhoenixGTS]

When the old guys say rear end clunk is normal - don\'t listen

My car has always had a slight clunk noise in the rear end when changing directions. During my time on the forum I have seen many noobs like myself asking about a rear end clunk. The thread is always filled with "it's just reminding you it's a Viper" follow-ups. Well a couple of weeks ago I thought my clunk got a little louder. Sure enough when I was installing Tom's 40mm rear calipers last week (i'll post about those later) I and fellow forum poster Jim Wilson inspected and rear and found the inside u-joint on the driver's side half shaft to be blown. The movement must have set up a vibration which in turn backed out two of the strap retention bolts. A little bit more and the shaft would have separated on the inboard side and made a mess. We tightened the strap up and I nursed it home. Honestly, during the drive home it sounded like the normal "Viper clunk." During the week I bought a used half shaft from WCV and am putting it in today. Moral of the story is don't always think it is just the normal "Viper clunk" if you have a clunking rear end. Inspect the u-joints. When I took the shaft off this morning I found that there was not one needle bearing in either of the opposing caps of the u-joint bolted to the differential output shaft. The monster torque of the Viper stikes again!

 

[Johann]

Re: When the old guys say rear end clunk is normal - don\'t listen

How many miles on those U-joints?

 

[PhoenixGTS]

Re: When the old guys say rear end clunk is normal - don\'t listen

How many miles on those U-joints?

The car has just shy of 30k, but I know that driver's side half shaft is newer than that (perhaps only 3,500 miles old. The very helpfull guys at WCV suggested that wheel-hop when the tires are spinning was the culprit. I am no burnout king, but a couple of times while experimenting on launches the wheels hopped a few times. If that is all it takes to hurt a u-joint that is pretty pathetic. I would hate to think I need a set of $900 upgraded half shafts to not have to worry about hurting the assembly. Perhaps when the previous owner had the new half-shaft put in the installers did not torque the band clamps tight enough and some movement allowed an early failure. In any event, I am really glad I caught it before it came apart and the half shaft started flipping around on the freeway. After some drama (which I might post about separately) the new half shaft is in so I am back to wheel-spin-city.

 

[BLUESNAKE367]

Re: When the old guys say rear end clunk is normal - don\'t listen

Outstanding point you make. I have my car serviced at the dealership, I hope inspecting the half shafts are a part of the service, but who can really trust them? I am going to check mine tomorrow..... thanks

 

[01sapphireGTS]

Re: When the old guys say rear end clunk is normal - don\'t listen

I don't have the clunk, but was going to do an entire underneath inspection this spring. Now I have a very specific thing to look for. Thanks Phoenix

 

[Jim Wilson]

Re: When the old guys say rear end clunk is normal - don\'t listen

Hey Michael, glad to hear you got the u-joint problem fixed. How do you like the new rear calipers?

 

[PhoenixGTS]

Re: When the old guys say rear end clunk is normal - don\'t listen

Hey Michael, glad to hear you got the u-joint problem fixed. How do you like the new rear calipers?

So far the calipers are a huge improvement, but due to my taller than stock tires, the fronts still lock up before the rears just like during our first test drive. I have now removed the seal in the proportioning valve in order to give maximum line pressure to the rear with the goal of getting all four to lock up at the same time. Once I test drive I am going to make a post about the whole caliper project. Thanks for the help on the install.