[carprigger35]

I built a truck over the past 10 months and now that it finished Im experiencing some major vibration through out the truck at about 55.I used all truck drive line components and did take into consideration that I would have this problem.

So my question is what ring& pinion size to I go junkin' for?

i used a Chevy SM 465 granny tranny and a 10 bolt rear from a 97 Saburbon,my tire size is 205/60/r15.

I would like to get a rather tall rato,..3.08,....2.73?

Any help and input would be greatly appreciated.

tim

[lmsport]

The vibration is probably the driveshaft due to bad driveline angles or simply out of balance or bad ujoints.

[carprigger35]

Originally Posted by lmsport

The vibration is probably the driveshaft due to bad driveline angles or simply out of balance or bad ujoints.

Everything's properly aligned,joints are new.My tire size is too small for the ratio ,Im just looking for opinions.It runs at 2,500 rpm at like 60 mph.

Thanks for the input tho,...

[lmsport]

Keep the rear you have and change the gear.
The unit you have is probably a 3.42, but might be a 3.23 or a 3.73.
If its a 3.42 and you change to a 3.08, you'll be going 68 mph at 2500. With a 2.73 gear, you'll be doing 76 at 2500.
I would be concerned that it will still vibrate whenever the drivehsaft speed equals 55 mph.

[carprigger35]

Originally Posted by lmsport

Keep the rear you have and change the gear.
The unit you have is probably a 3.42, but might be a 3.23 or a 3.73.
If its a 3.42 and you change to a 3.08, you'll be going 68 mph at 2500. With a 2.73 gear, you'll be doing 76 at 2500.
I would be concerned that it will still vibrate whenever the drivehsaft speed equals 55 mph.

Its not a terrible vibrating,it just seems that the drive train is going is WAY to fast for the over all wheel speed.Does that make sense.

Looks like im going to go with the 2.73s

Thanks again for the input!

Tim

[2old2fast]

What imsport is telling you is diagnose the vibration problem 1st, then if you want to change gears, have at it! You should not have a vibration regardless of speed/rpm.
dave

[carprigger35]

Maybe Im misdiagnosing the vibration all the way,considering this is a 62 year old truck with a modern drive train and a raspy little 300 hp motor.I do believe balancing the wheels may help too.Im sure when I get ALL these factors ironed out Ill be pleased with the results.

[big gear head]

If the Surburban is a 1/2 ton then the rear end that you have will be a 8.5 10 bolt. This is a very good rear end and should be more than enough for what you are doing with it. If it was a 3/4 ton then it is probably a 9.5 14 bolt. This is more than you need and is just adding extra weight to the truck.

As for the vibration it is probably in the drive shaft. If the drive shaft is not strong enough for the RPMs that it is turning then it will distort at speed and no amount of balancing will fix it. You need a drive shaft that is at least 3 inches in diameter and 3 1/2 inches would be better. If the drive shaft is very long then you need to go with 4 inches or more to prevent distortion. Most people with vibration problems will over look the real reason for the problem, which is almost always the drive shaft, due to diameter, length, RPMs, angles or other problems.

[carprigger35]

Originally Posted by big gear head

If the Surburban is a 1/2 ton then the rear end that you have will be a 8.5 10 bolt. This is a very good rear end and should be more than enough for what you are doing with it. If it was a 3/4 ton then it is probably a 9.5 14 bolt. This is more than you need and is just adding extra weight to the truck.

As for the vibration it is probably in the drive shaft. If the drive shaft is not strong enough for the RPMs that it is turning then it will distort at speed and no amount of balancing will fix it. You need a drive shaft that is at least 3 inches in diameter and 3 1/2 inches would be better. If the drive shaft is very long then you need to go with 4 inches or more to prevent distortion. Most people with vibration problems will over look the real reason for the problem, which is almost always the drive shaft, due to diameter, length, RPMs, angles or other problems.

Yes,you are correct that 10 bolt is a 8.5".Ill have to make another adjustment to my yolk angle.But then again I did just put this truck together,i didnt mention that it was bagged.So Im sure that playing with ride height a bit will help me out.The drive shaft is a stock 4.5"x61" unit out of a short bed.

Heres a few pics,...