Im running into some dead ends with th GP/Regal ppl. And Im pretty sure you can help me!

alright heres the Sit'iation

I have a 1996 Grand Prix with a 3100. the PCM is ODB-II. The Transmission is 4T60-E.

I am currently rebuilding an L67 from a 1997 Bonneville SSEi that is now deceased. Its heart will live on in my car.

So you guessed it, Im doing an l67 swap in my car and here are my questions:

Is the 1996 Bonneville SSEi really an L67 to 4T60-E combo?

If it is...

I would like to mate up my 1997 L67 to my 1996 4T60-E, will this work? I have come to discover that my 1996 PCM is the same as the 1996 Bonneville PCM. Would it be possible to flash my PCM with the 1996 SSEi codes, re-do my harness for the L67 and have it all work nice and neat?

Which leads me to this, does anyone have vacuum line and wiring diagrams scanned for a 1996 Bonneville SSEi???? I would be very very very appreciative!

Hope you guys can help! Frankenstein and i are depending on ya!

Hey Kazoo!

Yes the 1996 Bonneville is an L67 to 4T60-E HD combo, but the 1997 is an L67 to 4T65-E HD setup. I don't know if the bellhousing is the same or different--perhaps Turtle could help you out there--he did an engine transplant in his '92 Bonneville. He went from series I (L27) to a series II (L36) so he could possibly give you a heads up on some of the things to look out for. I know that motor mounts will be an issue--not that your motor mounts won't work, but the motor mounts are on the side for the Bonneville and in the front for the GP. As far as wiring harnesses and CPM'*, perhaps the best way to deal with that is to swap the entire unit.

One other potential problem to look out for. If you are mating the L67 to your GP 4T60-E tranny, be aware that it is not the same as the Bonneville'* transmission. Any L67 application with the 4T60-E actually had the 4T60-E HD transmission that had a beefed up final gearing and Diff. (although the diff is still the weak link). Don't do any massive burnouts or you will fry your open differential.

As for diagrams, some of the members here have some diagrams and schematics, hopefully someone will chime in for you.

Good luck!

Hello Kzoo right back at ya!

I have the motor mounts taken care of. The bellhousings should be the same, its actually a FWD GM standard if i'm not mistaken, and i know the differential is different, not concerned about that becuase i actually expect the tranny to break, but hopefully that wont happen within a year. Eventually i will switch to a getrag 282 when the time comes.

Will i run into trouble with the PCM throwing a code becuase of the differential? or worse yet causing the trans not to shift at all? If it'* going to be too much work i may just go ahead and try to cobble in the 282 right away.

I hope someone does chime in with diagrams, that would be very cool.

The 4T60E and 4T60E-HD transmissions are the same in most major parts except the torque converter is a little bigger in the HD version so the stall is ~2000 rather than 1900 for the regular 4T60E. Your swap should work well. And you are going to do like the Turbo Grand Prix'* and drop in a Getrag 282 but are you sure it will work for a 3.8L? I guess it should since the 3.1L Turbo'* used the 4T60E as well. Well good luck with your project.

I might be mistaken here, but I'm pretty sure the electronics for the 4T60E and the 4T60E-HD are slightly different. If that'* true (and it might not be) you would run into a PCM problem rather quickly.

Does anyone have the factory service manuals for 96?

I'd be tempted to just buy the chip for the 96SSEi. Your speed may be off due to the gearing difference, just keep in mind that the chip itself is fairly cheap. It'* the PCM that really sets you back. You may run into problems with VATS on the SSEi chip. You'll either have to rig a bypass or change your ignition switch. That'* assuming you don't have VATS on your GP.

You'll also have to take into consideration a larger exhaust. The stock exhaust on your 3100 won't cut it. You'll run, but it won't flow too well. Also consider installing a boost gauge for the Eaton. That'* the best indication something may be going wrong. It'* an invaluable gauge. Pontiac ditched the voltmeter and installed the boost gauge in that location for Supercharged models.

When you're all done, we can set you up with the part numbers for door and trunk badges to 'show off' what you have under the hood. Supercharged SE'* had a really slick simple "Supercharged" badge on each door and the trunk lid. 95BonnevilleSESC (your neighbor) can show you what they look like. His is the rarest of Bonnevilles.

I have a rather simplified schematic for the 96 SSEi (actually the same for all models). I'll scan it and email it to you as soon as I can.

To clarify, the 1995 Supercharged SE had two badges--one on each of the front doors, the 1996 and 1997 Supercharged SE'* had one badge located on the bottom of the rear deck lid. You could do any or all--depending on your preference. The Supercharged badge for the SE is the same as for the SSEi, without the "SSEi" above it. Look at Willwren'* signature for an example. You can also see them (barely) on my pick below. If you would like to get together some time, let me know.

Awesome, this is way more response than i've been able to get from anywhere else!

1. Hmm, scuse my ignorance but i have no idea what VATS stands for or what it is!

2. Boost guage is a definate!

3. The Getrag 282 is the same as the 284, but is readily available! as long as I pull a 282 from any GM, the bellhousing matches up perfect. Ask any L67-swapped Fiero owner! As far as the PCM, there actually is a manual mode that bypasses all the transmission logic! woohoo. its so easy its pitiful. The hard part is trying to put a clutch and a shifter in a car that never had one, but is exactly the same as other cars that did offer one! that'll take a year at least to come up with all the parts becuase they are all very rare now.

4. the 4t60-E'* electronics and vacuum work is the same as the 4T60-E HD, just like what was described before, there is a slightly different torque converter and a different final drive like you said. So i do see some programming problems with speed, but i do have the equipment to reprogram PCM'*, so this isnt a big worry to me.

5. I'd love to see that pic of the supercharged logo. but your link doesnt work!

So we know the bellhousings are the same and the electronics are the same. The problem will be whether or not I can get away with flashing my PCM to work like the bonnie, or is the whole thing different? Different connections, wiring scheme etc? Im worried about this VATS thing too, can you explain willwren?

Vats is the little chip resistor in the key. If you don't have it and the 96 PCM is looking for it, the car won't start. You'll have to find the pins for the PCM that are looking for it and trick it, but your reflash could beat that, too. The best thing to do would be to get the Vats module from the same bonneville, or perhaps another one, and insert a resistor inline. There are 20 different values.....might take awhile to figure it out, but it'* been done. The guys with remote car starters have to do it. We'll get you through that.

Sounds like you've really done your homework! Can't wait to see you do this. That schematic is REALLY on the way Got home late last night and was talking to Hector into the wee hours. I'll get it out to you today for sure.

SWEET THANKS!

I see now. I've never heard it called "vats"

My car has PassLock, and an aftermarket security system on top of that. Thats not even an issue for me. Yeah homework, and a GM guy and a couple of others who have swapped in this engine have been helping me! Im going for the records of cheapest swap and quickest swap....later Im going for most frankensteined freakshow car, a 5-speed 3.8 */C....then coolest looking and fastest

That'* pretty cool! You're gonna spend a small fortune in rubber to keep that thing on the ground!