Another gear ratio id ?

[SDlivin]

This is for the 9" rear. I have an open diff because when I tried the 'ol jack the axles up and spin the tire method, the other tire spun in the opposite direction. Also, I get inconsistent results when I try this method, the drive shaft seems to spin only when applying a little force or speed to turning the tire.

Next method I tried was the tape and string to the drive shaft, I then DROVE the truck forward exactly 1 rear wheel rotation.
What I am getting at the drive shaft is about 2 3/4 or 2.75 wraps of the string around the Dshaft.

The front axles has a tag that says 4:10, so I was assuming (and yes I know what that means) that the rear is 4:11.

What gives?
Would rather not have to crack the case if I don't have to at this time...

Thanks.

 

[kayakersteve]

I suspect your measurement is off

You should first try the counting method again. If you have owned this truck for some time and driven it at speed in 4-wheel drive, then I would say the gears are matched, otherwise you would have a thread about the chirping and noises that your truck/wheels make when in 4-wheel drive.;D

 

[SDlivin]

You should first try the counting method again. If you have owned this truck for some time and driven it at speed in 4-wheel drive, then I would say the gears are matched, otherwise you would have a thread about the chirping and noises that your truck/wheels make when in 4-wheel drive.;D

Good point, and good idea to elaborate on. Only had this vehicle for 9 months or so. Been working on it more then not, which is to say it has been in the garage more then not. With that said, I did get it out last month at the Bronco Daze event in Borrego Springs. Had it in 4 wheel drive for about 5-10' and something was binding terribly before something snapped in the front left. I think it was the hub and not an axle. Finished the trail in 2wd.
Currently building a D44 to replace the D30, which is the reason for the Gear ?'s, and why I haven't cracked open the D30 to see what actually broke. I'll do that when it's off the truck.

 

[kayakersteve]

In that case---

The ratios may not be matched. Try counting again. Its not a terrible job if you decide to open diff and can be a good time to check gears and change fluids.

 

[DirtDonk]

Hmm, it only spins when you try to do it faster or with more force? Is that with both wheels off the ground or one? Try putting one back on the ground and spinning the other one then to see what your results are.
If it still acts like it's slipping, somethings amiss. To say the least.

I suppose if it's a totally clapped out limited-slip, it could act funny and have some characteristics of an open diff, but it'd have to be totally faded to spin one wheel in the other direction I would think.

What does it drive like? What size tires? Is it a dog? It's not out of the realm of possibility that a PO pulled a donor chunk out of a passenger car and you have something in the high-two's for a gear ratio, but it'd be a total dog even with stock-ish tires. A 4-something would have some pep, and you'd be spinning the engine in the 3000 to 3500 rpm range on the highway.
That sound about right?

Paul

 

[SDlivin]

Hmm, it only spins when you try to do it faster or with more force? Is that with both wheels off the ground or one? Try putting one back on the ground and spinning the other one then to see what your results are.
If it still acts like it's slipping, somethings amiss. To say the least.

I suppose if it's a totally clapped out limited-slip, it could act funny and have some characteristics of an open diff, but it'd have to be totally faded to spin one wheel in the other direction I would think.

What does it drive like? What size tires? Is it a dog? It's not out of the realm of possibility that a PO pulled a donor chunk out of a passenger car and you have something in the high-two's for a gear ratio, but it'd be a total dog even with stock-ish tires. A 4-something would have some pep, and you'd be spinning the engine in the 3000 to 3500 rpm range on the highway.
That sound about right?

Paul

Well... already started tearing it apart...

It seems to drive fine, doesn't miss a beat. Now, don't get me wrong, it doesn't run like my camaro, but that's a different story.
33" tires...
Got the axles out now. 28 spline.
Should the bearings come out when you pull the axles?

Tomorrow I might get around to pulling the pumpkin, I'll post some pics and you guys can tell me what gives. Thanks.

 

[DirtDonk]

Good show. You'll appreciate going to the trouble now, to make sure and also changing the oil. Yes, the bearings should pull out with the axles. Didn't they?
Some axles (Ford 8.8 and a lot of the GM car axles) have the bearings pressed into the housing, and the axle is actually the inner race. Saves money and weight, but in my opinion, making the axle a wear item is a total cop-out.
With the 9", the bearings press on to the shaft and then a retaining/keeper ring presses on as a safety measure. The retainer plate (on the outside of the bearing of course) holds the whole thing in. As you've no doubt found out at this point.

Paul

 

[SDlivin]

Good show. You'll appreciate going to the trouble now, to make sure and also changing the oil. Yes, the bearings should pull out with the axles. Didn't they?
Some axles (Ford 8.8 and a lot of the GM car axles) have the bearings pressed into the housing, and the axle is actually the inner race. Saves money and weight, but in my opinion, making the axle a wear item is a total cop-out.
With the 9", the bearings press on to the shaft and then a retaining/keeper ring presses on as a safety measure. The retainer plate (on the outside of the bearing of course) holds the whole thing in. As you've no doubt found out at this point.

Paul

Yup, different then my Camaro rear end axles, was surprised to find the bearings come out with the axles. Hopefully get to the pumpkin today, if not tomorrow and I'll get some pics posted.
Makes sense that this rear end may have come from another donor vehicle as the pinion/yoke has a funky support bracket on the top side of it.
Someone before mentioned maybe a Torino.

 

[bluebronco69]

if it has a support bracket over the pinion its probably from a car, that is to control axle wrap i think.

 

[Madgyver]

Do the string method on both front and rear driveshafts at the same time. lock up both front hubs and check to see if they are engage, (push vehicle while t-case in neutral).

Tape each string to bottom of drive shafts and push vehicle one full tire rotation. this while tell you if you have different gear ratios if they don't match.

http://classicbroncos.com/tech/whats-my-gear-ratio

 

[SDlivin]

Okay, pumpkin out....

Here's the pics...

Counted the ring (44 teeth) pinion (16 teeth)
So 2.75 gears in the rear! Open diff?

Amazes me, the more you dig into cars the more you gotta scratch your head and wonder WTF were they thinking.
Now I'm really wondering if the front d30 is 4.10 as the new tag on the diff says. I guess it doesn't matter at this rate, replacing with the D44 anyways, but this may explain why the first time I tried it in 4x4, something immediately snapped in the front.

So now the question is: what gears to run, since I'm replacing them anyways.

I have a D44 w/ 3.54 gears in it, and a 3.73 and down Auburn Pro LS carrier (not currently in the D44.) and of course the Ford 9 with 2.75 gears.

Trying to do this on a budget, but get something I can use.

Thoughts?

 

[DirtDonk]

Freeway-Flyer gears!
Aren't you glad you took it out now? Good catch. Just think, you could be one of the few that ends up thinking that something more in the 3.50-ish range would be an upgrade for larger tires!
At least you can count the teeth on the 44 by just taking the cover off. Simple and quick, other than the tie-rod being kind of an annoyance.

What size tires you going to run eventually? What transmission? What usage?

Paul

 

[SDlivin]

Freeway-Flyer gears!
Aren't you glad you took it out now? Good catch. Just think, you could be one of the few that ends up thinking that something more in the 3.50-ish range would be an upgrade for larger tires!
At least you can count the teeth on the 44 by just taking the cover off. Simple and quick, other than the tie-rod being kind of an annoyance.

What size tires you going to run eventually? What transmission? What usage?

Paul

yeah, no wonder it seems to do fine on the freeway.70-80 no problem, any faster and I just don't feel too safe.

33" tires now, 35" once d44 goes in. Original 3 sp manual tranny now, Nv3550 eventually (in garage, just need to rebuild and buy adapters etc.. $$$) Dana 20 'T' shifter.
75% on road, 25% off road, no hard core rockcrawling, but want it to be capable.

whatchya think? can I get away with the 3.54 gears, which would mean just buying for the rear and installing the LS diff in the front.

Using the gear calculator: 3.50 gears, 35" tires, say's I'd be @ 2400 rpm @ 71 mph with the 3 spd, and 91 mph @ 2400 rpm with the NV3550.....

 

[Viperwolf1]

You'll want at least 4.56 gears to make use of that od gear.

 

[DirtDonk]

If you were planning an automatic trans, I'd say you'd be happier with 4.10's, but go for it anyway. With the manual trans though, and one with an overdrive to boot, I'm going to have to say no to the 3.5 series. With 35's, even on the street, I'd say the 4.10 is the minimum, and 4.56 is not out of line. I know some think that might be a bit low, and you can survive just fine on the taller gears, but gears are something I consider a "do only once" kind of thing.
So the 4.10 might be the compromise gear. Still decent acceleration from a stop, and capable off-road with the NV's 4.5 or so first gear, but certainly no deep off-road gears.
Anything taller and you might as well not spend the money on an overdrive transmission. If you think you might even consider the 3.5 gears, then plan on an NP435 for a tranny too. Lower first and no overdrive in the way. You save some money, but I think you'd be happier in the long run with the NV3550 and 4.10 gears.

Paul

 

[SDlivin]

I like the idea of 'done in one', or do it once and right...

With that said, and since I'll be changing out gears in both the front and rear regardless....

4.10's or 4.56?

Funny how what you think is going to be a small, simple, cost effective upgrade on paper ends up snow balling into a major project/purchase once you break into things...

thanks for the advice folks.

 

[Skiddy]

i would do the 4.56's

 

[kayakersteve]

4.11 unless going to BIG tires

This way, you wont have to change out the front which you already stated was 4.10. Will save money. If you are going with 35" tire, on the other hand, you may want 4.56.

Edit - Read last post and in that case if planning on doing both = 4.56

 

[SDlivin]

Okay so 4.56 it is....

In the pics posted can someone tell me if that is an open differential or not?

Also, for the 9" since I am going to the 4.56 R&P, I'll have to change out the differential as well?
With new install kit?

This is a 28 spline ford 9, with 11" drum brakes.

Am I better served trying to find a big bearing 31 spline, and doing the gear upgrade in that?

thanks again.

 

[sprdv1]

4.11 mostly street, 4.56 mostly trail