Anyone know a quick way I could check to see if my tranny is for sure an SI while its out of the car?

Ive searched and posted on the topic before, but have never really gotten a straight answer

 

Anyone?!

 

I needed to know this once too.

So i searched and in 3 minutes I had the answer. You must have forgotten to click the "archived content" button.



Here are the results of my test.

Mark both.




Check after 10 rotations of mainshaft.


Mystery solved.

 

Its in the FAQ sticky post, along with some handy casting stamps that will help too.

 

that they all had the same 1st gear

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 7808 &raquo;</TD></TR><TR><TD CLASS="quote">that they all had the same 1st gear</TD></TR></TABLE>

*twirls finger in air*

All the USDM Si and dx trans all had the same 1-5 (hell even reverse was the same) gears and the only difference was the painful 3.888 Final drive that killed the dx trans.

Please note this is only true with 88-91 L3 transmissions. a 92-95 dx trans is not the same ratios as a 92-95 si trans.

 

someone please explain final drive

 

When old muscle cars used to swap out their rear end, it was changing their final drive.

A higher number final drive will accelerate through the gears more quickly (more mechanical advantage) and a lower number will hurt acceleration properties as the engine struggles to climb each 100 rpm (less mechanical advantage)

Final Drive is the ultimate decider of your acceleration and top speed:

Higher FD: faster acceleration, lower top speed
Lower FD: slower acceleration, higher top speed

Does this help at all?

 

how is the final drive calculated

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 7808 &raquo;</TD></TR><TR><TD CLASS="quote">how is the final drive calculated</TD></TR></TABLE>

Take the number of teeth on the ring gear(attached to the differential) and divide it by the number of teeth on the countershaft. The countershaft is the one with the teeth that ride on the ring gear

For example:

Ring gear 68 teeth...divided by 16 teeth on the countershaft = a 4.25 Final Drive Ratio