transmission advice

**butt86** · 09-29-2009

i already pm'ed the transmission guru maybe he will chime in here too.

-planning on a swap for my 97 regal gs
-im putting in a transmission from a 99 regal non-hd
-using intense/zzp pcm for the 3.29's
-would like to use the stock GS convertor, can i use the non hd convertor and use a non-supercharged flywheel? (for the different size convertor)
-using a non hd R axle with the non HD diff ( in know its weaker but its temporary)
what else do i need or what havent i thought of chime in and let me know thanks!

**Scimmia** · 09-29-2009

The converter you use is determined by bolt pattern on the flywheel. Stock flywheel means stock sized converter. You can get the flywheel drilled for the smaller converter if you'd like, I wouldn't put a flywheel from an L36 on an L67, they're balanced differently.

You will NEED to use the passenger axle from the non-SC car unless you swap your HD diff over.

**butt86** · 09-30-2009

k thanks yeah i was thinking the flywheels would be balanced differently, and i have the axle from the non SC car. thanks!

**Scimmia** · 09-30-2009

I just noticed that you said a PCM programmed for 3.29s. Don't forget that the Regal LS had a 3.05 diff, so that's going to be a problem unless you swap in the diff from the HD trans, which is 3.29.

**butt86** · 09-30-2009

Originally Posted by Scimmia

I just noticed that you said a PCM programmed for 3.29s. Don't forget that the Regal LS had a 3.05 diff, so that's going to be a problem unless you swap in the diff from the HD trans, which is 3.29.

did not realize that the diff in the LS trans was a 3.05... can anyone else confirm this?

**QwikGT** · 09-30-2009

i believe 305 gears are in the impala....regal is the indentical twin to the grand prix so it would have 329's in the ls/gt and 293's in the gs/gtp

**Scimmia** · 09-30-2009

*sigh* why is nobody believing me on this point lately. I drive a Regal LS, and currently on a transmission that I built. I can absolutely guarantee that it has a 3.05 diff. If you want more proof, here's a screenshot of my stock tune.

I may have a pic around of my stock diff that shows the sun gear, if you want to count teeth.

**butt86** · 09-30-2009

Originally Posted by Scimmia

*sigh* why is nobody believing me on this point lately. I drive a Regal LS, and currently on a transmission that I built. I can absolutely guarantee that it has a 3.05 diff. If you want more proof, here's a screenshot of my stock tune.

I may have a pic around of my stock diff that shows the sun gear, if you want to count teeth.

lol no i dont need to count the teeth

so swapping the diff out for my stock (GS) diff it will give me the 3.29's?

**Scimmia** · 09-30-2009

Yep, the HD diff is 3.29 and the gears on the chain are going to be 35/35, so you'd end up with 3.29 overall. Not only that, but you could use your stock axle.

**butt86** · 09-30-2009

Originally Posted by Scimmia

Yep, the HD diff is 3.29 and the gears on the chain are going to be 35/35, so you'd end up with 3.29 overall. Not only that, but you could use your stock axle.

k well that would work out well. so i would still need to have the computer reprogrammed from the stock 2.93's but thats it?

**BillBoost37** · 10-01-2009

There's a couple ways to go about this one. What is the current problem with your 97 trans?

Reason I ask is you could swap the diff over, but will need to also swap the output shaft (easy to do with both transmissions out of the car). I've been talking with Doug on the gear ratio and checked the ATSG book I have last night. It shows the non-hd W body (Regal/GP) as 35/35 drive and driven sprokets and a 3.29 diff. This is the same diff ratio as the HD diff. The only thing you'd need to do is reprogram for the 3.29 ending ratio vs the HD 2.93 ending ratio. (Caused by the HD 37/33 sprokets vs the 35/35 of the non-hd)

The 97 output shaft and diff are slightly different than the 98+ because the 97 year used a clip taht requires you to install to hold the diff on the output shaft vs the 98+ where you had a compression ring where you tap the shaft to install it into the diff. Splines are slightly different on the shaft to diff as well.

Overall though, I've done this conversion and it's easy. If your 97 diff, diff cover and ouput shaft are good, I'd suggest swapping them as they are stronger than the 99 non-hd parts.

**Scimmia** · 10-01-2009

Good catch on the output shaft, Bill, I'd completely forgotten about the difference there.

I still maintain that the Regal has a 3.05 diff, though

**BillBoost37** · 10-01-2009

The ATSG could very well have a misprint. I know the Bonnevilles only came in 3.05 and 2.86 ratios. GP GT's are supposedly 3.29.

**BillBoost37** · 10-01-2009

Ok guys, I have confirmed the gear ratio of the Regal LS with Pat. Pat knows every little minute detail that most of us would never learn or forget in moments. He's a library and I do rely on him alot at times.

Doug is not on crack. Standard Regal LS diff ratio is 3.05