Hey guys...

Pulled out my stock diff yesterday and installed the 4.57R from Stratocaster.

As soon as I took it up to about 40mph, I noticed a vibration... Around 45-55 it's really strong, feels like the rumble strips on the freeway, above 75 it's still there, but due to the frequency you don't feel it as much.

I've read that it could be inner cv but it seems like a bizarre occurence that it would happen the same time I swap differentials? Also heard that it's LSD? How likely is that?

I'm running 75w-90 Redline Gear Oil, and did the 3 heat cycles- though it's been making the noise since I installed it.

HELP.

 

Whoever told you it's the LSD is probably on some form of LSD (hehe), and should never be trusted. We have a no clutches in our LSD, only gears. If your LSD goes, heh, you'll KNOW it.

As for the vibration, I'll let xviper or slowS2k offer suggestions on that. However, I don't think the diff itself would cause a "vibration", though it can cause a "whine" noise.

Also, try something other than redline. While we only have 2 UOAs of it so far, it breaks down very quickly, at twice the rate of mobil 1 and LE 607 diff fluids.

 

but there's a bunch of things it could be. I would start by making sure you bolted everything down to the correct torque specs.

 

Who installed the gears in the pumpkin and who installed the pumpkin in the car?

 

The pumpkin was built by Stratocaster / Ricks.

I installed the pumpkin, torqued everything to Helm Manual specs.

 

It could be the position of the drive shaft. I had a vibration like what you described and I moved my driveshaft a few holes and it was gone. You might try rotating your drive shaft and rebolting it to a different location. Try something that is 90* from where it is now. It's a balanced assembly from the plant and you might even see a small weight tacked to the driveshaft that is evidence of the previous balance. That's why in the helms it calls for marking the location of the shaft to the pinon and the axles to the spindles.

HTH

 

Exactly! Did you mark the orientation of the output shaft to the 1/2 shaft holes?

 

[QUOTE=xviper,May 11 2006, 12:58 PM] Exactly!

 

You send the output shafts to Rick's? I thought you would yank yours out before sending.

 

i edited my post.

the output shafts do get put into the new diff. however, i think it's a moot point since they will not necessarily be the same position they were in the old diff.

as for getting the two to match up, can just those tiny half shafts really cause a vibration just because they aren't mated up the same way? FWIW mine and Keith's were never marked and they turned out ok.