? on trans swap (slightly different car)

[93ParkAvenue]

I have a 93 Park Avenue base model with no traction control. I guess it mattered because the yards I called all asked that.

I found a trans out of a 93 Park Avenue with a supercharger (also, no traction control) with 39k miles on it. The guy told me it will work but I need to swap over something and it would work. After looking at it, I assume he means the whole final drive assembly. I took my old housing off to access the final drive and was presented with the pretty picture of broken teeth, so I can't use that one.

Now my question is: do I have to swap in another assembly or can I use the supercharger's transmission as is? Or will the computer need to be flashed(or chipped, w/e they use)?

Other than that, any good sites with the torque specs for my car? I changed out the rear main while I was that far in and need to torque the bearing cap and flexplate at least.

Thanks a ton!

[robertisaar]

can you pull the model codes for the two transmissions you have? there seem to have been quite a few 93 4T60Es used in the C-bodies.

3BTW
3CLW
3CSW
3CXW
3WAW
3YMW
3YZW

if they are 93s, then they should be one of those, they had various final drives and VSS reluctors, if you're lucky, you might have an exact match, otherwise you would need to have the calibration changed to match.

[93ParkAvenue]

How do you pull codes? I tried looking GM Vin cards but they didn't specify transmission. Then I looked at the rpo codes in the car and didn't see any 4 digit codes. Finally, I looked over both transmissions and didn't see any 4 digit codes there either.

Thanks

[3400-95-Modified]

there should be a metal tag on the back of the trans leg near where the exhaust comes down from the engine.

[93ParkAvenue]

there should be a metal tag on the back of the trans leg near where the exhaust comes down from the engine.

Donor transfer has a tag. These are what I found on it.

613BTW
W18T0

Stamped into tag were these : 032 4A 02

Big letters : BT

And at the bottom right in small letters : 8678222

The broken transmission is tagless. And unfortunately appears to also not be the original transmission.

[robertisaar]

well, your replacement trans is a 3BTW model. you may have to pull the diff cover and possibly side pan on the broken one and verify final drive gear set, chain set and VSS tooth count.

3BTW is a 3.33:1 final gear set with a 37/33 chain set to make it an actual 2.97 final drive. there are 31 teeth on the VSS reluctor and it would have came paired with a 1897RPM stall converter.

[93ParkAvenue]

I pulled both covers off but am unsure of what to count. I've looked for differential diagrams but haven't found any. The reluctor has 30 teeth. The gear on the inside of the assembly (that has the r smalller gears that rotate around it) has 38 teeth unless I counted wrongly.

And I don't see anything really behind the side pan. What should I be looking for?

[robertisaar]

it's been a while since i've gotten this deep in a 4Txx but i believe the two parts you'll have to count teeth on are shown here.

EDIT: and in the side-pan, you should see a pair of sprockets connected via a dual chain. those are part of the calculation as well.

[93ParkAvenue]

I don't know how it's going to be possible for me to count the sprockets you speak of. I'll take another look with a flashlight this weekend and see what's going on.

What would happen if I just put this trans in? If the computer needs to be reprogrammed, do you know how much that is approximately?

Thanks a ton. I've never had to work on auto transmissions before(thankfully).

[robertisaar]

just putting it in, the final drive and VSS reluctor MIGHT be different, so anywhere from an incorrect odometer/speedometer to the PCM disabling 4th gear / TCC lockup due to large amounts of positive or negative "slip".

shift points will be the same as before, but if the FDR/VSS is different, they'll feel different as well.

those are the only big things i can think of. not sure of too many people playing with the older 3800s or if i even have the XDF to play with it, would need the BCC/BIN from the current MEMCAL to know.

[93ParkAvenue]

Man, what a headache..

The guy at the yard spoke to "somebody" who told him that all I should need to do would be to change out the vss. I figured the sensor was the exact same between models so I discounted what he said anyway. However, I told him of my situation and he said if isn't right when I put it in, he'll make it right(I'm assuming he means getting me the correct diff). I knew him in high school so I'm not too worried about him not keeping his word. I've been at a standstill for a couple of days though because of all this.

Should there be a need to change the stall? With all the metal that circulated through the old trans, I'm not comfortable switching anything over to the "new" one(save for the 4 new solenoids I just put in it...).

[robertisaar]

IIRC, you MIGHT be able to swap the VSS reluctor over to the new one.

then the only issue you might have to worry about is the wrong chain drive or final drive.

[93ParkAvenue]

IIRC, you MIGHT be able to swap the VSS reluctor over to the new one.

then the only issue you might have to worry about is the wrong chain drive or final drive.

I took a quick peek at the reluctor thinking I might be able to swap it but I couldn't come to a conclusion about that.

IF I was able to, what would having a different final drive or chain drive be problematic if the reluctor was giving the correct speed to the ecm? I figured it would be just like changing the gearing in a rwd axle, but obviously I'm only speculating.

EDIT: also, if I go ahead and put the transmission in(only because of time limitations and weather), if TC lockup was disabled, would I damage the trans by riding in 3rd until I can properly switch out the final drive assembly OR flash the ecm?

[robertisaar]

interestingly enough, GM built their FWD transaxles to have the VSS located after the final drive.... so any change in final drive ratio or chain ratio will not cause issues with the speedometer, as long as the VSS reluctor matches what the ECM is calibrated for. so the only real issues are shift points potentially feeling too high/low and the ECM disabling TCC/4th gear due to it thinking the TCC is slipping.

sticking in 3rd, the ECM will eventually try to turn the TCC on in 3rd gear, so the fake slip issue will still be there, so i wouldn't bother attempting to disable TCC.

[unchained01]

I for one would not use the converter I would use the new solenoids. And i would widen my search for the correct trans And hopefully you have a place like we do here. They deliver free to businesses up to 50 mile away. And make daily runs Good luck !!! Sometimes these things just need time to be worked out