[Blue Z Cowboy]

Well, finally got the axle back from 4wps and threw it back in there...I dont know how I went with 3.73's for so long. Being able to smoke them 35's is great, but im scared of the govbomb.

Now that theyre in, the speedo is way off, like 20 mph off, how do i fix this? I cant put a hypertech in my truck... Also since I put the gears in I get a vibration that increases with speed, I have a feeling it could be my driveshaft, maybe I knocked a weight off? What do u guys think?

 

[Rednecked_4x4]

if your gears are new they need to be broke in.... that could be the vibration.

 

[Dark Eternal]

ummm a vibration isnt good.... make sure to break the gears in and if its still there check the balance of your shaft, if not then you have a bad instal.

BTW get a nelson tune, screw the hypertech.

 

[Blue Z Cowboy]

break in....forgot about that, lemme search, ill have more questions im sure....

 

[Blue Z Cowboy]

Ok just searched here and FSC, very mixed opinions on this... What do yall think?'
Here's how Ive driven so far....
test drive, 20 min on street/hwy then it sat
got excited, spun em a little on my street
drove 45 min, 70 mph
cruised some trails at the lease
returned home
Just went to get cigs.....

Is there anything cheaper to fix the speedo, im kinda strapped for cash right now and I am saving for front gears...? Nelson tune is what I need, but hes sure proud of it...

 

[Eisenfaust]

Cheapest thing is the superlift tru speed, but even that isnt cheap.

 

[Derek]

Cheapest thing is the superlift tru speed, but even that isnt cheap.

i believe they are running a special on these at natonal tire and wheel
atleast there were 2 weeks ago when i ordered my lift

 

[Blue Z Cowboy]

Anything I need to be doing to break these suckers in? I just drove it to Port A and I got a real bad vibration at about 75 and after that it kept getting worse, with some vibe noise.... So I kept her around 70

 

[vhato]

The vibration could be loose pinion preload (doubtful). Disconnect the driveshaft from the pinion yoke. Push in and out on the yoke. There should be no play at all. It should only spin. However this only checks to see if the pinion is too loose. I have seen it a few times. It still could be a little loose. No way to really check it without pulling the carrier out. Something else is carrier bearing preload could be loose causing the carrier to vibrate.

The pinion angle could be off which would make itself apparent after lowering the gear ratio. The driveshaft should be in a straight line right into the pinion. Meaning the pinion yoke should point right in line with the driveshaft. Of course you are running 42's so you would need an extreme amount of lift and proper pinion angle would be impossible to find without blowing pinion bearings. So there isn't much you can do if you pinion is pointing high enough.

You could also have thrown a weight on the shaft.
Another thought is the U-joints are loosening up. May need to be replaced.

Chances are REAL good the vibration was always there, but at a higher speed with 3.73's that you never really drove at (100+ MPH). Now that you have a lower gear ratio the truck "Tacs" higher at slower speeds. A vibration at faster than highway speeds is not uncommon when going to 4.56.

Good luck trying to find it. You will probably go crazy first.

 

[Whifflebat]

BTW get a nelson tune, screw the hypertech.

No worky, he's got a TBI. I think that you may be able to pick up a chip off tbichips.com that will fix it, but be sure to email the guy first and make sure he can correct for it. If not then there is a way to solder a dip switch into your pcm and adjust the gear ratios that way, but I don't have a clue (tech article is on fsc (or it was))

 

[Blue Z Cowboy]

Of course you are running 42's so you would need an extreme amount of lift and proper pinion angle would be impossible to find without blowing pinion bearings.

I wish man, but the info was good, I'll need to look into it....oh yea, I never marked the shaft to the yoke and I just threw it in there, could that be a problem, even if it isnt im gonna go 180 it and see.....

 

[Blue Z Cowboy]

well I 180'd it and same ol shit, so I went and got a big ass hose clamp and threw it on there to where the nut was where original weight existed at one time and all is well, I got up to 100mph and it rode like a dream, so if anyone is lookin for a quick fix to a thrown driveshaft weight go grab a hoseclamp and paint it black!