I have wanted to discuss this topic for a while, because I always read about CV joints breaking; especially on Turbos...

Would not having an LSD actually put more stress on the CV joints, because one wheel would have more power directed to it?

vs. an LSD setup where both wheels have the power split between them..

What do you guys think?

 

Makes no difference as each CV is it's own system. What does make a difference is the sudden plunge and cage twisting from a loose trans hanger, usually the inner driver's side goes first especially on a V8 swap. The factory trans hanger even new is a poor design at keeping the trans from slopping side to side even under hard cornering.

 

Good question.

I'd say the bigger enemies to CV joints are heat (which dried up lubrication) - especially on the driver's side inboard one, since it's so close to the exhaust, and over extension, caused by the transmission rotating under load due to bad engine mounts.

 

My car only had 58K miles on it before I converted it and I could literally push the trans by hand 3/4 or more inches from side to side and when I removed the CV's and axles to build my own chromoly, the CV's were worn and loose just from the weak 4-banger

 

What is the best way to test a cv joint to see if it's dead or not? Example: last night (something) broke in between my back tires. not sure if it's my cv joints or my tranny, or both. but my passenger's side cv spun by hand, while the driver's side did not. (tires were on the ground, car was in neutral)

When I put the car in gear and let off the clutch, there is a nasty grinding sound and no power to the wheels.

I would like to spend smart money and replace what's broken, so any tips or advice is much appreciated.

Thanks

 

i agree the greatest enemy is a bad trans mount or one that just flexes too much... go to solid or do the urethane mod and i'll bet your cv's will last a lot longer...

 

Inner or outer CV joint spins? What about the axle (the rod between the joints?)

My guess is either the outer joint has had all of its bolts back out, or you've had a CV joint failure.

Shouldn't be rocket science to figure out... See what's moving and what isn't. Where the moving and non-moving parts (should) connect is where it's broken.

 

1. Check CV bolts
2. If CV bolts good, pull axles, inspect CV cages...
3. If cages good, inspect axle/race splines
4. If Axle/Race splines good...tranny bad (my condolences)

 

If your tires are on the ground, and the CV Shaft can spin, there is something wrong with the CV joints... <--- It doesn't matter if your Transmission is in neutral or in gear with the tires on the Ground.

Sounds like the CV joint that is attached to the wheel is broken! Which is way better than a Transmission issue, which as i stated in your original post would be very surprising.. 944 Transmissions are Strong like Bull!

 

One more question for this Topic:

If you have an LSD and a CV joint breaks only on one side, will the other side still get power??

 

Yes, but it will also have the pleasant side effect of destroying your LSD clutches.

 

Ok, and with this said;

Since the LSD effectively spreads the power across both axles (instead of directing all the power to one side or the other) wouldn't this put less stress on the CV Joints?

 

No doubt, on an early car. The problem with late cars is the stupid mount setup that allows massive transmission movement, which is what destroys the cv's.

 

The reason i bought up this question is my CVs have been failing for months;;; (Torn Boots, vibration under heavy acceleration/when additional weight is in the car) yes, i know i should just replace or rebuild them... and i will

But i am just surprised when i read stories of people's CV's breaking, and their boots aren't even torn.

Also my Tranny does move quite a bit side to side...

I have an LSD in my car, and was thinking maybe they have survived for so long because full power never goes to just one side...

 

Actually, i was thinking about it... With the tire on the ground resisting spinning, and with the power of the engine encouraging spinning, this gives you the largest "delta force" - or the most stress a CV joint can see.

With an LSD, the force of the engine will be applied to the CV joints while both wheels have traction. Once both wheels break free, then the stress on the joints will be reduced. But, if one wheel has lost traction and the other wheel still has traction, it does stand to reason that the CV joints on the traction side will have to endure the brunt of the engine's power.

On an open diff car, when one wheel breaks traction, not only will it reduce the stress on that CV joint, but it will also reduce the stress on the other joint (the power will take the path of least resistance and make the wheel with less friction spin).

Again, this is somewhat theoretical... CV joints are quite strong and can hold up to a lot as long as they're operating within their designed parameters.