72 521 diff.

[konig209]

So my diff started whining today only on deceleration in neutral.

 

Checked fluids full. Talked to my dad said its pretty much toast. There a 521 @at pick n pull i can get. Might be good might not who knows. My question is should i just go back to stock or is there a beter diff that goes streight into the stock axel?

 

Or is this a common issues of whining with a simple fix?

[wayno]

So my diff started whining today only on deceleration in neutral.

 

Checked fluids full. Talked to my dad said its pretty much toast. There a 521 @at pick n pull i can get. Might be good might not who knows. My question is should i just go back to stock or is there a beter diff that goes streight into the stock axel?

 

Or is this a common issues of whining with a simple fix?

 

 

What color was the fluid in the diff?

Was it silver, black, brown, dirty white/brown, or yellow?

What engine do you have?

I know I should know what engine, but I don't recall half the shit in my own trucks anymore. :hmm: :lol:

[konig209]

 

 

 

What color was the fluid in the diff?

Was it silver, black, brown, dirty white/brown, or yellow?

What engine do you have?

I know I should know what engine, but I don't recall half the shit in my own trucks anymore. :hmm: :lol:

 

it was darker than satans asshole with a regualar gear oil green tint to it. Does that mean anything?

Stock l16

[konig209]

[DAT510]

No metal shavings or chunks?

[konig209]

Nope none at all

[datzenmike]

Check and fill the transmission first. It takes GL-4 80w90 weight oil. Transmissions will whine when low.

[wayno]

Virgin gear oil is yellow, and that is what you want to find when you stick your finger in the top hole when checking the level.

If you pull your finger out and you can see a metallic color with the black, or find a bunch of metal on the drain plug, then likely its toast.

I just seen the photo of the gear oil, so was there a build-up of metal on the magnet on the drain plug?

I don't know much about the L16, I had that engine in my 71 briefly, I could not go 70mph on the hiway without being floored most the time, and it would not make it up to the hanggliding launch without flooring it and not slowing down, because if I slowed down, I couldn't get it going again, so I yanked that POS out and put a L20b in it and never had a problem getting up the hill after that.

If you drive it like a car, and stay on regular roads, you might be able to use 389s, but you likely would not have a hole shot anymore, and I am unsure how it would drive at hiway speeds.

Any 520, 521, 620, and early 720 pumpkins will bolt right into your rearend housing.

[konig209]

http://s58.photobucket.com/albums/g275/rocket_04/?action=view&current=video-2012-07-11-20-32-35.mp4

 

here is a vid doesnt do justice but works.

But thanks for the tips

[datzenmike]

That's the rear end grinding not whining.

[konig209]

That's the rear end grinding not whining.

that too lol

started whining now its grinding.

[wayno]

It's hard to tell, but that didn't sound good to me.

Did you hit the brakes just before shutting it off?

Set the e-brake, put it in neutral, get under the truck and twist the driveline back and forth, how much play is there in the rearend flange?

If there is an eighth inch play, you need to start looking for a rearend one of these days, if there is a quarter inch play, you need to find one fairly soon, if there is MORE than a quarter inch play, you will be screwed if you keep driving it.

[konig209]

It's hard to tell, but that didn't sound good to me.

Did you hit the brakes just before shutting it off?

Set the e-brake, put it in neutral, get under the truck and twist the driveline back and forth, how much play is there in the rearend flange?

If there is an eighth inch play, you need to start looking for a rearend one of these days, if there is a quarter inch play, you need to find one fairly soon, if there is MORE than a quarter inch play, you will be screwed if you keep driving it.

no brakes that was third gear i put it in neutral and thats how fast it slows down in the end i yanked the e-brake

[wayno]

I was wondering if it stopped that fast on it's own, it sounded like it stopped because of binding, and that was exactly what it did when the e-brake was pulled.

You need to check the pinion gear play.

If it is making a lot of noise, and your sure it's the rearend, and not the driveline, then find another set of gears.

[datzenmike]

that too lol

started whining now its grinding.

 

As you can see it getting progressively worse.... fast! These things can suddenly lock up while driving at speed... not at all good.

[konig209]

I was wondering if it stopped that fast on it's own, it sounded like it stopped because of binding, and that was exactly what it did when the e-brake was pulled.

You need to check the pinion gear play.

If it is making a lot of noise, and your sure it's the rearend, and not the driveline, then find another set of gears.

 

thanks for all the help ill get down there tommorow and check play.

Mike thanks too started last night today is worse if driving down the road i stick my head out the window and i can hear the gears eating each other.

[wayno]

thanks for all the help ill get down there tommorow and check play.

Mike thanks too started last night today is worse if driving down the road i stick my head out the window and i can hear the gears eating each other.

 

Check the driveline U-joints also, sometimes the driveline acts like an amplifier, but generally there is a vibration also when a u-joint is going bad.

[konig209]

 

 

Check the driveline U-joints also, sometimes the driveline acts like an amplifier, but generally there is a vibration also when a u-joint is going bad.

i was down there it as in gear and its deff the gears nothing else. Told my nephew to pop it outa gear and its all diff and i can hear the gears bad

[konig209]

So quick questions

 

1 if i get 720 pumpkin for the diff on my truck it will bolt right in right?

 

2 if it does will that mean ill speed up slower But ill cruise at lower rpms and have beter gas milage?

[wayno]

So quick questions

 

1 if i get 720 pumpkin for the diff on my truck it will bolt right in right?

 

2 if it does will that mean ill speed up slower But ill cruise at lower rpms and have beter gas milage?

 

 

It depends on what gearing you have now, it's likely 437s, so if you can find a set of 411s, or 389s, then your rpms will be lower going the same speed.

Yes the early 720 diff. will bolt right into your 521 rearend housing.

I have not a clue if you will get better mileage, sometimes if the engine isn't strong enough you could end up not being able to start very easily, and you also could not have enough power to hold a hiway speed in 5th if you have a 5 speed, say in a big head wind, there are a lot of varibles involved.

Do you just drive around town, or do you spend a lot of time on the hiway?

Datzenmike says that L16s like to rev, so if you put 389s in your truck, the engine might not like them lower rpms and preform poorly on the hiway.

[datzenmike]

Get a 2wd diff.

[konig209]

Get a 2wd diff.

2wd diff of of what????? Like i needa know cause mine is about to take a shit still driving it like that :’( but i have to its my dd and i neded to go to work.....there is a 521 at pick n pull here in town and a 720 the both pumpkins are still there both are 2wd but i wanna know what would be beter i have a very strong l16 threw 130psi all the way across all 4 (not sure if thats good tried multiple times different tools as well) with a four speed tranny

[ggzilla]

Lower RPM is better for fuel economy at highway speeds, regardless of the engine. Even with the L16. Doesn't matter if it likes to rev, you keep the piston speeds down and friction is reduced 4x !!! And if you need to pull hills, just slip it into fourth.

 

The real problem is taking off and around town it might be underpowered. Try driving your truck now, starting out in 2nd and shifting sooner. That's what a smaller ratio will be like.

[wayno]

Go to the wrecking yard where the 720 is, and look on the ID plate on the pass. side in the engine compartment, on the bottom right, there will be a number, you want a 41(411) or a 38(389), anything lower you don't want 37/35/33.

I think the 411s would be the best, but you likely can use 389s.

Before you buy the part, get under the truck, grab the pinion flange, and check how much play it has, if more than an eighth inch, walk away, pull the bottom drain plug, and stick your little finger in the hole and scrape some of the oil off and look at it, if it is anything other than yellow/dark yellow, walk away.

You should also double check the gear ratio to make sure it is what it is supposed to be, to do this, you need to pin/anchor one of the wheels so it cannot move, then go to the other side, mark the top/side of the drum/wheel, mark the side of the driveline/pinion flange, now turn the wheel/drum on your side two complete turns, counting how many times the driveline/pinion flange turns, if the other side moves, it won't work.

If it(driveline/pinion flange) turns just over 4 times, that would be 411s, if it turns just under 4 turns, that would be 389s, do you get the idea?

I will repeat, if the otherside moves, you will not get an accurate ratio.

I have done a lot of these gear changes, don't buy anything with bad colored gear oil, or anything with more than an eighth inch play in the flange.

To remove the pumpkin the fast way, have a GREAT pair of wire cutters, cut the brake lines and e-brake cables, remove the four nuts on the back of the brake plate, remove axles, remove driveline from pinion flange, remove the 10 nuts holding the pumpkin in place, remove pumpkin, check everything inside before buying.

It takes me about half an hour to remove one of these if everything comes apart properly.

[konig209]

Go to the wrecking yard where the 720 is, and look on the ID plate on the pass. side in the engine compartment, on the bottom right, there will be a number, you want a 41(411) or a 38(389), anything lower you don't want 37/35/33.

I think the 411s would be the best, but you likely can use 389s.

Before you buy the part, get under the truck, grab the pinion flange, and check how much play it has, if more than an eighth inch, walk away, pull the bottom drain plug, and stick your little finger in the hole and scrape some of the oil off and look at it, if it is anything other than yellow/dark yellow, walk away.

You should also double check the gear ratio to make sure it is what it is supposed to be, to do this, you need to pin/anchor one of the wheels so it cannot move, then go to the other side, mark the top/side of the drum/wheel, mark the side of the driveline/pinion flange, now turn the wheel/drum on your side two complete turns, counting how many times the driveline/pinion flange turns, if the other side moves, it won't work.

If it(driveline/pinion flange) turns just over 4 times, that would be 411s, if it turns just under 4 turns, that would be 389s, do you get the idea?

I will repeat, if the otherside moves, you will not get an accurate ratio.

I have done a lot of these gear changes, don't buy anything with bad colored gear oil, or anything with more than an eighth inch play in the flange.

To remove the pumpkin the fast way, have a GREAT pair of wire cutters, cut the brake lines and e-brake cables, remove the four nuts on the back of the brake plate, remove axles, remove driveline from pinion flange, remove the 10 nuts holding the pumpkin in place, remove pumpkin, check everything inside before buying.

It takes me about half an hour to remove one of these if everything comes apart properly.

 

Thanks for the info guys that will help alot if the 720 dont work out i guess 521 it is :-/