switching Q45 transmission from 95 to 93 year

[rsiwicki]

can this be done....switch the 95 transmission & TCU with a 93 transmission & TCU. I want the lower gears in the 90-93 transmission's for better acceleration versus the 94-96 gears and since my current transmission is going to be replaced anyway, I just thought that if I could do this mod that it would be a great mod while getting something that already needs to be fixed...

[Q451990]

I think you'd need the 93 ECU as well... My guess is that other parts (like the CAS) that changed with the 1994 revision may work differently - so it may not work. Also doesn't the 95 use a LAN for lots of stuff? Not sure if that's tied into the ECU or not...

I'm not sure that I'd try it - but I'm sure others will weigh in here soon with more information. If you're feeling brave, you could try the 93 ECU with it before buying the transmission and see how it works (don't blame me for smoke or fires) - if it works then you'd probably be OK.

I don't know if anyone else has ever tried this or not...

Heath

[rsiwicki]

thanks for your comments...and yes I will be changing the TCU as well to match the year of the transmission. I have been watching ebay to try to pick up an extra TCU for the earlier years and to stick it in just to see what kind of response I get differently. Like you said, if the different TCU does not do too much different except change the shift points, then I think that I also should be good to go using an earlier transmission. There is a guy on ebay selling transmission's really cheap and he said that he had about 4 or 5 of them sitting around the shop. He does not know how to tell if the transmission is a 51x65 or 51x79 model. Does anyone know how to tell which model a transmission is by visually looking at it withouth opening the guts?

I am new to all this terminology so I don't understand a couple of the terms you are using....what part is a "CAS" and what is the "LAN" thingy.

I think that AGM over in Australia switched transmission's to the earlier year, but I can't tell from all the posts what he ended up doing in the end. I have emailed him and hope to hear from him soon on what transmission he used.

[Rex]

CAS - Crank Angle SensorLAN - Local Area Network

[elwesso]

Youd probably have to look at the serial number to see what kind it is for sure....

Id think youd be able to do it, I dont jthink youd need to get a new ECU or anything.....

[maxnix]

Not sure if the earlier TCU (1993) will work with the LAN system on the later (1994+) cars. Didn't someone mention an interface problem?

[elwesso]

I thought the LAN only dealt with stuff dealing with the body. IE the ECU and TCU wouldnt have anything to do with it......

[rsiwicki]

thanks all for your comments....I spoke with Joe and the pin connectors are the same so should be just a plug and play type switch of the old TCU versus new TCU. I have the local dealer checking for me on the LAN or CAS issues. They don't think that this will be an issue initially and will let me know. They think that the trans TCU is almost totally independent of everything else so should not be an issue. Joe also mentioned that he thought that he as heard of others at their shop who have switched to the earlier transmission & tcu and did not have any problems. Also from what I can tell on AGM's posts, he did go with the earlier transmission & TCU for his 94 supercharged beast. AGM just got back his converter so we shall see how his setup runs.

In the mean time, if anyone would be willing to rent me a 90-93 tcu where I would just unplug mine and plug in the new one that would be great. I would only need it for a few days...a week at most so that I can get over to the dealer and see how my engine ecu, lan, cas, etc. reacts what codes if any appear. I am thinking about $50 and if I break it I will buy it and I can give you a deposit for the full price of the TCU ahead of the game so that when I return it to you I just get my deposit back. If you are interested, please contact me. Maybe somebody has an extra TCU lying around that they want to rent to me ?:)

[maxnix]

Contact Heath 1990Q45 for the extra ECU TCU rental before he puts it up for sale.__________________Brian1995 Q45 & Q45t & 2000 Q45

Discover the power of the button!

[rsiwicki]

thanks all for your comments....based on what AGM has researched and from what the dealer has told me, it looks like I can just drop in a 90-93 transmission without needing to switch the TCU...I am going to get the JWT TCU anyway...please see the JWT TCU Info thread for more info in the Infiniti General forum...

It looks like I will be running even with all you 90-93 Q's soon after I get the new transmission with the better gears.