Hi everyone, this is my first post on Saturn Forum, I wanted to ask about the changes and what is the same about the engine harnesses on the 95-99 DOHC. This is for a 95 sw2, The reason I'm asking is because the automatic transmissions from the years 93-95 are giving me issues. The problems pertain to shuddering on the shift from 1st to 2nd, half of 2nd gear, clunk from 2-3 which is usually valve body from what I've heard, slam or clunk from the last shift on normal mode at around 33-35 mph. Now would that be 4th or OD. I've been using the Blue Valvoline Bottle transmission fluid when I recently changed out m transmission a couple weeks ago. I've never really have been fond of that fluid. After a couple thousand miles I was starting to lose second gear and reverse completely! The transmission came out of a red 94 sc2 with 266k on the odometer, the odometer didn't work so I assume the miles must be higher than what it showed. The car sat in a field the previous owner stated, they also stated they replaced some solenoids and the valve body from a car with 130k.I checked the readings of each one and they stayed in the normal ranges. So, I changed the transmission fluid again and I replaced it with Type H Plus from AutoZone. 4 Quarts. Now I was reading on some Honda Forums that that is compatible with Dex lll. It's pretty much Honda Z1 fluid. One thing I found out on this transmission was on the dipstick it stated use only DEX llE. Dex llE was before Dex lll. Something about it is mineral oil I read? Could someone confirm this? Okay Dex lll, it should work if I could get it. Now GM wants to push the new DEX 6 I believe what it is now and saying its compatible. It's not. But the Type H Fluid does work for right now. Still no second or reverse so the car is only running 3 forward gears from what I've counted. I've haven't had a problem with the blue jug from Valvoline on my 02 sl2 with 130k. I know this is a long post, so back to the main topic. If I were to convert a 95 sw2 into let's say a 99 DOHC, since it had the harness going through the fender and I would have to take my dash wiring out for the electrical and cluster and computer, would I be able to use a 99 or 00-02 engine or transmission, or would I need a bcm? Did 99 have a BCM? I know that 99 had the revised engine, transmission and the aluminum intake manifold like previous years. It's a big undertaking but I have some OEM Saturn shop manuals at home. what do we think? Thanks!

 

We think we don't know which car you're talking about for the first half of your post. Not assuming anything other than it's possibly a 99 s x 2.DOHC.

The s car did not have a BCM until 99 I believe.
95 is actually OBD1 not OBD2 like the '99.
So if you are considering putting a 99 DOHC into a 95 DOHC car, you would have to change the entire wiring harness not just under the hood, but you would have to take all of the PCM driven functions in the 95 and wire them to the BCM that you bring over with the engine, along with wiring everything as needed to the PCM that you bring over from the 99.

Not sure how you deal with passlock, since 95 didn't have it, but you need it to start and keep the car running. I'm sure there's a hack for that somewhere but I don't know it. The issue is whether the ignition switch from 95 can be swapped out with a 99 plus ignition switch. Either fits or it doesn't and you'd have to rewire it to the BCM and make passlock work.

As for the transmissions, I don't remember where the transmission control module is, but it may be that the 93 to 95 transmissions had an OBD1 based TCM to match the rest of the communications with the 95 PCM. Not a transmission expert on these cars but that would be my first guess. Communications from 97 up would be based on an OBD2 compatible TCM.

I would look up the part numbers for TCMs for both the 95 and the 99 version of the MP2 or is that the mp3. One of them is for DOHC automatic and more of them is for DOHC manual. Having a brain fart sorry.

I sincerely doubt they are the same. That might explain some of your transmission issues although the valve body and the input shaft nut may also be contributing to the slamming.
I think I remember that the clutch pack for second gear also comes into play with reverse, but I may have dreamt that so I would check. Would point to a bad solenoid possibly not commanding things to move as designed.

Please clarify the vehicle with the shifting issues and the vehicle you are considering for the swap in. Thanks

 

I apologize for the confusion, the whole post is about the 95 sw2 and seeing if i can swap a 99 engine and transmission into it. Pretty much the whole dash wiring would come out and i would switch steering columns. Since pass lock. i would see if i could swap in the whole dash from the 99 if the mounts line up. The transmissions would be an mp7 for auto, what is entailed for replacing clutch pack? do i have to pull the transmission out for that?

 

In all honesty, trying to essentially make an OBD1 1st Gen believe it's a 3rd Gen OBDII based vehicle AND have everything operate properly is a tall order. Because you are ditching the 95 PCM for the 99 PCM and BCM, I think the only way to ensure that everything is routed correctly when the smoke clears is to swap the entire 99 harness into the 95. As in the whole car. Even doing that, the exterior lighting may be different.

You would also need to swap out the fuse boxes inside and out and the power distribution blocks beneath them in order to match the 99 harnesses.

You'd have to swap in the 99 cluster since it's digital or has 95 is mechanical for the mileage.

The physical dashboards between 1st and 2nd generation differ so putting in a third generation dashboard easily seems very unlikely. The third gen cluster might fit in the first gen dashboard.

The BCM/SRS is going to be looking for all of the additional airbags in the 99 that physically do not exist at the 95.

Also looking for the additional collision sensors which don't exist unless you bring them over too. With the additional airbags, you can't. Also, any additional collision sensors on the 99, even if you hook them up in the 95: with the 99 brain, will probably report the SRS as inactive due to it's inability to contact either the missing sensors or the missing airbags or both. Then you are going from two airbags to zero because the SRS system will not arm.

Also, 95s did not have drls ( I know 97s did) . Not sure how to satisfy the BCM. Having transferred the fuse blocks and distribution panels beneath them, the 99 will also come with control logic and a spot for a DRL relay in the fuse box you brought over.

This is an obscene amount of work for the return you will receive.

I would sooner recommend you do a manual swap in to get rid of that crap automatic, but that has its own fun aspects.
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It's at times like this that I continue to curse the ****er who let that site go down the drain. 20 years of wisdom gone.