[tyang82]

ok so I've been doing some reasearch on doing a complete swap from a 7mge to a 7mgte with the r154. i see that the rear differential is different from the late 80's and early 90's. Is it necessary to also swap rear differentials?

 

[sixpack]

No.
About the only major difference are the ratios.

Seeing that you are NA now, I am guessing you have the 4.3 ratio gears,
but a check of your car's build tag will give a trans/axle code, I can tell you exactly what you have.

Most of the later turbo cars had a 3.7 ratio.
Some people like them to limit wheel spin off the line.
Personally, I like to put enough tire on a car to do that.
I run 4.56 gears on the street, and 5.29 gears for the strip, but I run an automatic.
A 5-speed does not require ultra deep gears like that.

 

[tyang82]

thanks 6pack, you're much help. i appreciate that very much

 

[Miiike]

the other difference is the N/A diff might not be LSD if it wasn't a "sport package"

 

[tyang82]

damn. where can i look to see if it is limited slip diff?

 

[tyang82]

ok, so i was now wondering if the MK$'s differential will fit onto my MK3?

 

[Miiike]

Jack the back up and spin one wheel, if both wheels go the same way it's LSD, if they spin opposite of each other it's open. And no, the MKIV diff won't fit right on as far as I know.

 

[tyang82]

so which one is better, the 4.3 or the 3.9?

 

[Miiike]

Since you're going GTE, the lower ratio the better because you'll have longer gearing, so the 3.9 or a 3.73 if you can find it would be your best bet.

 

[tyang82]

i see an 3.9 on ebay. thanks MIKE

 

[sixpack]

Yeah, if your not willing to put big/quality tires on the car, go with the taller gears (lower numericly).
But if your willing to put more traction under it, the lower gears (higher numericly) will launch better.