Help, fixing Differential Ratios.

[miguelmcv]

I being searching for 4 days and can't find much.

I did read a lot about what causes different ratios, Tranny, rear end, T case.

But, The answer that I am trying to know,,,, I just, Can't find it.

I put a used tranny in the car, I open it to inspect and everything was good, except the Differential, I am talking about the Big Differential, The one where the Axles attaches to, (I am not talking about the Center Differential).

The Differential was damage, So I put another one.
I have 1 tranny internals of the 89 to 91 gear set, and 1 tranny with the 93 to 99 gear set.

So I install an 89 91 Differential into a 93 99 tranny (internal).

So, my question is.

Is an 89 91 Differential the Same Ratios as the 93 99?.

I have some chirping tires when turning sharp and I just check and found out, that I have different Ratios.
Even going straight, It feels like I am using the E-brake.

I know that you might think that I have a different Tranny, or T-Case.

But, NO.

I Do have the wright Tranny and T-Case along with the Rear Differential.

I have being reading that,
When the Center Differential goes bad, It makes the tires to chirp when turning, But, In my case, I know is not the Center Differential, which I open the tranny and check everything before putting into my Car.

I read how to test for Different Ratios, which is.

Putting a tape at the tires and Drive straight and check for the tape to be the same way you put them (alighted).

So I did it, I drove around 120 FT (straight line), and one tire did 1/4 turn more then the other.

So, It means that I have different Ratios, but, WHY?.

I was going to take the tranny out and see, But, which is a little bit of work taking that down, I thought to ask, before I tear it down.

Any one with some good knowledge can jump in and give some advice, on what to look for, or where to start.



Thanks in Advance.

 

[jw4free]

Wow. A lot going on there. What year is your rear differential?

What year center differential?

What year is your front differential?

What year is your transmission?

Here's some light reading.

http://www.dsmtuners.com/forums/dri...d-transmissions-bar-codes-serial-numbers.html

There is an excellent thread that details the different ratios by model year. I can't find it. It should probably have a sticky in the Drivetrain Tech.

 

[miguelmcv]

Wow. A lot going on there. What year is your rear differential?

What year center differential?

What year is your front differential?

What year is your transmission?

Here's some light reading.

http://www.dsmtuners.com/forums/dri...d-transmissions-bar-codes-serial-numbers.html

There is an excellent thread that details the different ratios by model year. I can't find it. It should probably have a sticky in the Drivetrain Tech.

I all ready saw that,

But my probles is not about identification codes, which I have just the internal gears.
But I do know that both of the trannys came from a 95, and rear end is from a manual, wich they all are the same ratios except the autos.

I keep searching but have no luck.

 

[jtmcinder]

I read how to test for Different Ratios, which is.

Putting a tape at the tires and Drive straight and check for the tape to be the same way you put them (alighted).

So I did it, I drove around 120 FT (straight line), and one tire did 1/4 turn more then the other.

So, It means that I have different Ratios, but, WHY?

I have never heard of this test and it really doesn't make that much sense to me because you'd have to match the tire pressures to the corner weights for it to really work.

The much more straight-forward test involves lifting one side of the car and, with the car in gear, rotating one raised wheel and watching the other. If you have equal gearing to the front and rear, the opposite wheel will rotate (backwards) at the same rate. This test doesn't depend on tire diameter and/or slippage.

As to the chirping, this is most-likely caused by having different ratios to the front and rear, and therefore heating up the VC on the center diff to the point of it locking. When that happens, you've got what is effectively a welded center and all the chirping etc that goes with that.

 

[miguelmcv]

I have never heard of this test and it really doesn't make that much sense to me because you'd have to match the tire pressures to the corner weights for it to really work.

The much more straight-forward test involves lifting one side of the car and, with the car in gear, rotating one raised wheel and watching the other. If you have equal gearing to the front and rear, the opposite wheel will rotate (backwards) at the same rate. This test doesn't depend on tire diameter and/or slippage.

As to the chirping, this is most-likely caused by having different ratios to the front and rear, and therefore heating up the VC on the center diff to the point of it locking. When that happens, you've got what is effectively a welded center and all the chirping etc that goes with that.

Well,,,
It does make sense to me.

I am concern to the air presure, but, for only 120ft, is to short space for that amount of rotation diference (1/4 of wheel rotation)..

Any ways, I found tne video were shows, how to test the tranny and T-Case, for the ratios..

I will test and report the resulta.

 

[miguelmcv]

Updating my Rations inspection.

I drop the T-Case and test it, to see what year was it, and It was from late year (95).

I test the Tranny as well, and found out that,,,,,,,,, It is an early tranny (97, 99).

The tranny is a 95.

But, when my (awd swap), I open the tranny to check and see if everything was OK.

The differential bearings were bad, so I replaced all the differential with another one that I had in my extra tranny.
I did this, Because I didn't have the tool to remove the bearings.

So, I think the other tranny was an early tranny.

Well, thanks for the help and support.

I think this thread is getting Close.

 

[miguelmcv]

I just want to let know that.

I drop the tranny, open it, and it had a 58 teeth Front Differential, So,
I took it off and install a 57 teeth Front Differential.

I checked the Center Differential and it was in perfect Conditions.
Also, I checked the VC, and it was in good conditions as well.

So, now, I drove the car and it feels more better (no more crimping tire).