97 SSEi 4T65E-HD swap into a 95 Monte Carlo...
 

Is the 97 Bonneville SSEi 4T65E-HD the same as a Grand Prix GTP 4T65E-HD?

If not, what parts are different?

I searched on here (and clubgp and mymonte) and found a bit about a transmission range selector, but not much else. I heard that the torque converter is different, but I'm planning on using a 245mm torque converter (4T65E non-HD) mated to a stock 97 Z34 flexplate.

The GTP 4T65E-HD will bolt in and I have a wiring harness that is OBD2 and will let me use any 4T65E. I also have tuning software for the PCM that can account for any gear ratio changes.

Thanks.

Tim

Your 95 PCM may be the hybrid. Not sure about the MC. If that's the case, it'll make the PCM alot more difficult than just the gear ratio.

Yes, the TC's are different, but you sound like you have that covered. You'll need your driveshafts (The Bonneville's are longer).

Well, the engine is very similar to the GP and should bolt up. I think there are some subtle differences, but you should be fine. Gear ratio will be your biggest concern, not sure if there is a difference there from the gp to SSEi. I would consider getting a cradle out of a 98-99 LTZ or Z34 that has the L36 NA 3.8 cause the motor mounts will be the same for it. (not sure if the 3.4 cradle mounts are different)

I already have a 96 and 97 PCM and wiring harness for a 3.4 DOHC with the 4T60E (96) and the 4T65E (97). I also have a 96-97 Z34 DHP PowerTuner.

I think I can mate the inner part of the Bonneville axles to the outer part of my current Monte axles.

Cradle- I'm not sure. The 97 Z34 came with a 4T65E and the 3.4 DOHC and I'm not aware of any cradle differences in the 95-99 Monte's.

Gearing. Is the SSEi gearing the same as the 2.93 GTP gearing?

Thanks!

Tim

3.05 for 4T65E
2.93 for 4T65E(HD)
3.06 for 4T60E (rarely 2.84 or 3.33)
2.97 for 4T60E(HD)

question for you: are you just using the Transmission, or both tranny and Supercharged 3.8? If just the HD tranny, then the issue you will have it that it has some more items in the computer than the non-HD, which might cause some issues. If this is something you can modify with the PowerTuner, then you should be fine.

that 3.4 is TOTALLY different than the 3.8
i doubt any thing from the 3.4 will fit the 3.8

Yes, the 3.4 is completely different from the 3.8. They both share the same bolt pattern though and the transmissions are interchangeable if the proper flex plate and torque converter is used.

I'm keeping my 3.4. Why would I want a L67? I just got back from a Grand Prix dyno day and put down more power than every L67 that was not running nitrous. So yes, I'm using JUST the transmission from the L67.

The 4T65E and 4T65E-HD should be identical electronically. The PCM's may be programmed differently, but a 4T65e computer should be able to control shift points, line pressure, and everything else in a 4T65e-HD AFAIK.

Tim

I think the question was asked because you neglected to tell us all the details before.

Sorry about that. I had posted here and clubgp. Looks like I forgot to include everything I should have here. :oops: Also, reading that last post I think I came off as an A-hole. I was trying to joke about it, but it's kinda hard to type sarcasm on the internet. :(

I'm planning on using a 97 Z34 engine, PCM, and wiring harness. They were bolted to a 4T65E from the factory. My 95 engine would work, but the 97 has an extra knock sensor and exhaust ports that are twice as big.

I've got to say that there have been a LOT of times I have seriously considered a complete L67 swap including the engine, but I think I must be a bit of a masochist for wanting to stick with the 3.4 DOHC. 8)

Total setup: 95 Z34 car, 97 Z34 engine, pcm, and wiring harness, 97 SSEi 4T65e-HD, and PowerTuner to control everything.

Tim