Transmission Swap Fittment (Regal to GP)

**indygrandprix** · 03-08-2014

Bought a transmission from a 98 Buick Regal GS and am going to put it in my 01 GT. I already read up on the issues with the fittings for the tranny lines needing to be switched. Not a big deal. My bigger concern was that the casting on the tranny's bellhousing from the Regal says 910 and the one on my GT says 901 and then the one in My GTP says 911. I just want to make sure everything will bolt up before I tear into my GT.

Other questions I also had...

Is the 4th shaft hardened in the HD tranny before 03?

Anything I should replace besides the axle seals and input shaft seal before putting it in?

Will the regal torque converter work in the GT?

**Sven the Sexman** · 03-08-2014

I'm not 100% as to why, but the interchange from car-part.com is showing 97-98 GTP and GS only work in those cars. I think there were some subtle differences but am not sure. Regardless, the torque convertor for the Regal won't bolt to a L36 flexplate, so you'll need to use the one from the GT trans. Also, the gear ratios are going to be wrong so you'll need to change the trans settings in the PCM so that works right. And, you need the P/S axle for the HD differential.

**indygrandprix** · 03-08-2014

I know about reprogramming for the Gear Ratio change. I'm gonna have dsmuts do that for me after I get it changed over.

If I have the flex plate from the L67 engine will that bolt to the L36 crank so I can use the Regal torque converter?

**jsnyder49090** · 03-08-2014

I would change the filter and clean out the pan now.As far as I know only the line hook ups may be different.See if the boxes on the trans are the same.The 4th is supposed to be hardened in 03 up.I had an 03 trans rebuilt and the splines had some wear still.I am not sure if I have an early 03 or what but I replaced it.

**Sven the Sexman** · 03-08-2014

Originally Posted by indygrandprix

I know about reprogramming for the Gear Ratio change. I'm gonna have dsmuts do that for me after I get it changed over.

If I have the flex plate from the L67 engine will that bolt to the L36 crank so I can use the Regal torque converter?

If you have the L67 flexplate then you can run the L67 torque convertor.

**l67ss** · 03-08-2014

Actually yes an l67 tq converter WILL bolt to an l36 flexplate. Its the l67 flexplate that wont bolt to an l36 tq converter. L36 flexplates have dual bolt patterns, l67s have one. Only issues youll run into is the tranny lines and dif gear ratio. Also your car will be a lil slower. You grabbed the matching pass cv axle too right?

**Sven the Sexman** · 03-08-2014

My L36 flexplate wasn't dual pattern.

**Scottydoggs** · 03-08-2014

seems like you got it all covered, the only other thing that you may have to do is the PNP swap, if your 03 has an internal shift deal.

the 98 regal trans has that black box by the shift lever its external. theres a how too here if you need it.

**l67ss** · 03-08-2014

On all the l36s i dropped trannies on they were, there was actually a debate on a gtp fb page that saved my butt. They were having the reverse debate. Im planning on bolting an l67 to an l36 trans pulled my flywheel and it was single pattern. I grabbed flexplate off an 01 monte ss, dual pattern

**Sven the Sexman** · 03-08-2014

I had a L36 bolted to a 4T60 (97 GT)

**l67ss** · 03-08-2014

Yeah i almost made the same mistake on pnp switch myself

**l67ss** · 03-08-2014

Ive got a 3400 bolted to an l36 4t65

**darkhorizon** · 03-08-2014

PLEASE do not swap flex plates to fit the torque converter... If the bolt holes do not line up use a grinder to make them bigger or smaller.

**indygrandprix** · 03-08-2014

I'll have to see if it's dual pattern when I tear into it. I was gonna do a build thread on how to Put a HD trans in a GT car. I know its not much different from R&R of any 4t65e trans but I figured i might as well.

As far as the axle I was just going to get a new one from NAPA and tell them I need it for an 01 GTP. That will get me the correct length axle right? I replaced the Driver Side one about 10k ago fortunately I hadn't replaced the pass one yet.

**l67ss** · 03-08-2014

Grind on a balanced part? Anyway flexplate will bolt up anyway

**l67ss** · 03-08-2014

Yeah thatd b the right one

**indygrandprix** · 03-08-2014

Originally Posted by darkhorizon

PLEASE do not swap flex plates to fit the torque converter... If the bolt holes do not line up use a grinder to make them bigger or smaller.

Why do you say not to swap the flex plates?

**indygrandprix** · 03-08-2014

Originally Posted by Scottydoggs

seems like you got it all covered, the only other thing that you may have to do is the PNP swap, if your 03 has an internal shift deal.

the 98 regal trans has that black box by the shift lever its external. theres a how too here if you need it.

I haven't read anything about a PNP switch swap. My car i'm putting the 98 tranny in is an 01 tho so I shouldn't have to right? It's just 03+ that had internal PNP switches?

**l67ss** · 03-08-2014

That and 2000+ monte/impalas

**Scottydoggs** · 03-08-2014

98 has this box by the shiftier lever.

if the tranny in your car has this box its a direct swap. if not you need to follow this how to.

http://www.grandprixforums.net/threa...21#post1090321