Rear differential Questions

[born2drv]

OK so my differential is making a whining sound now (I guess 411rwhp on a diff over 200,000 mi on it killed the sucker). It seems to be getting slightly louder too.... so here are some questions I'd appreciate if anyone could answer:

1. How bad is it to drive with a whining differential for a month or so until I get new parts? Could this damage my tranny (auto) or engine?

2. How do I know what kind of rear diff I have? It's a 88 turbo auto tranny (from canada if that makes a difference) I know you can get different gearing, etc.

3. What is the best gearing to get for an auto tranny where I can cruise in O/D at say 80mph @ 3000rpm, or whatever... how would I figure that out? What's the best in terms of performance?

4. What else should be changed when replacing the differential???

 

[IJ.]

Front Diff not making noise?

As long as there's Oil in it the noise will just get a little worse with time but shouldn't cause any catastophic failures.

Auto's are usually High 3's but without pulling it and counting teeth you can't be 100% certain.

 

[Nick M]

1. You will be fine.

2. The clutch packs indicate LSD, and counting teeth and 1st grade division tell you the ratio.

3. 3.73, becuase I am close to that.

4. Having an extra pinion bearing wont hurt. Sometimes the press has a mind of its own.

 

[born2drv]

OK cool.... so I guess I have a 3.73 as well then... I'll have to figure that out. I'll probably just have jawsgear rebuilt mine and buy an aluminum driveshaft from them while I'm at it...

thanks for your help

 

[87CandyBlueT]

Yea I have the 3.73 and i can cruise 80mph @ 3050ish RPM but I have a manual not sure of the auto difference.

 

[Nick M]

The R154 has a slightly shorter ratio at .75:1 and the A340E is .70:1

 

[jdub]

OK cool.... so I guess I have a 3.73 as well then... I'll have to figure that out. I'll probably just have jawsgear rebuilt mine and buy an aluminum driveshaft from them while I'm at it...

thanks for your help

If yours is an '88 turbo, it should be a 3.90 ratio. They changed to 3.73 in '89 for the turbo models.

Edit: Thought you might like to know. Took my Supra out on the highway today...at 3000rpm, got 83 MPH. I have a 3.90 differential.