The title pretty much says it all. Will a 99 Eldo tranny with a VIN 9 fit in a 95 Seville SLS with a VIN Y? Thanks.

I have done a little research on this and every source I talk to informs me that as long as it is a Cadillac 4t80e (Oldsmobile has one for the Aurora),it will mount up to a Northstar engine. I have a 94 with vin code Y and I was asking the same question. A local mechanic said that even though they have different converter clutches(vin y=viscous converter clutch) vin 9=torque converter clutch they mount the exact same way.:D

Mounting may not be in issue but the gearing is different in a Vin 9 and a Vin Y. Make sure you're computer won't have a problem with this...

My 2 cents...

Even if the trans is from the same year as the car, it doesn't mean it's going to work right. For example, 1998 has 4 different transmissions listed for the 9 motor alone. It would be an expensive lesson to find out that the PCM doesn't recognize the trans.

The final drive is different in those two transmissions and it will cause immediate SES light due to codes setting. I would find the same trans that you have...a vin Y... If it was a vin Y it would work fine. The model year doesn't matter in that case....just the vin Y so it will have the same final drive. Otherwise it will bolt up fine.

Depending on when the 95 Seville was built it might or might not have a VCC in the torque converter. Originally, the 95 4T80E for an STS had a TCC. The VCC was substituted for the TCC mid model. So , a 95 might have a VCC same as the 99 would. After mid95 all the Cadillac 4T80E transmissions had VCC.

Those two transmissions will mechanically interchange..i.e...you can bolt it in....but the final drive ratio will be different and cause the SES light to illuminate immediately and you will not be able to "fix" the problem. You need to find a vin Y trans. The trans with the VIN 9/L37 engine (300 HP) has a 3.71 final drive and your SLS with the VIN Y/LD8 engine (275 HP) has the 3.14 final drive. Not compatible inside the computer calibration and there is no readily available cal for the PCM that would work. If you do buy the 99 trans you could swap the final drive from your original trans if it is OK.

Hey guys thanks for setting me straight on this issue and saving jc some money and loss time.:tisk:

Thanks for the replies. I didn't think it would work, but it was worth a shot.

OK, I am fixing to buy a transmission and I just need one last clairification. Will any year transmission work so long as it is a VIN Y? Or do I need a 95 and down transmission with a VIN Y. Again Thanks for all the help.

Jason 95 Seville SLS.

I'm curious whether there are any manual transmissions out there that will at least fit in a seville without too much trouble even if it doesn't bolt right in.

The junkyard is saying that only a 95 transmission will work. They have both a 94 and a 96, but they are saying only a 95 will work. I think he is wrong, but I need to know.
Edit:
Also, how do you tell a VIN 9 tranny from a VIN Y tranny? The tag on my transmission has a code AA on it, but I can't find anything that tells what the codes mean. I just don't want to get burned and have to install the tranny and then pull it back out again. Thanks.

You should be OK with most any year 4T80E transmission. It doesn't have to be a 95 or earlier. That would matter if you had an STS since the STS had a different style lockup torque converter in it but the SLS would have the VCC and any later year trans should work fine...as long as it was from an SLS not an STS.

Well, I got the 96 and I have it installed. To my delight, when I dropped the pan I found the new style solenoids already installed. Today I am going to fill it up with fluid and take it for a test drive. Wish me luck and thanks for all of the help.

Well, I got the 96 and I have it installed. To my delight, when I dropped the pan I found the new style solenoids already installed. Today I am going to fill it up with fluid and take it for a test drive. Wish me luck and thanks for all of the help.

Yay! Let us know how she runs.....(like a bear I'm sure)

Does the 4.0 Northstar Jr in an Aurora share the bellhousing pattern with the rest of the GM FWD V6's like the L36 and L67s?

Thanks,

IT WORKED!!!! The only way I could tell it was shifting was by watching the RPM's, it's that smooth! I want to thank everyone that replied, espically bbobynski. Thanks again!