q45 trans swap from 93 into a 90

[djauto]

I have 2 q45's a 90 and 93 the 93 is wrecked with a good trans, the 90 the trans is out. I put the 93 trans in and it looked the same and all connections are the same ,,, when i was done the trans does nothing,,, so i called a junkyard and they informed me the 90 is its own trans.. Well i have the 93 trans in the 90 all hooked up ok what can i do to get this trans to work in my 90 I have the whole other car so what parts or computer would i have to change thanks for any help Dan

[rsiwicki]

should work just fine as I put a 92 transmission into my 95 car. Be sure you keep the 93 TCU and put it into your 90 car...this has the 1st gear start. There are others that have much more know how on this but you should not be having any problems

[djauto]

The trans will do nothing ... 1st problem is the shifter even though its in park is acting like reverse. because my reverse lights go on, the car wont start either, (park) i have to put it just a hair above neutral and then it starts. When it does start i run it through the gears and i get nothing the rpms change a little bit and it looks like maybe something is happening but nothing no movement no slip no nothing Do you know if the computer should be swithced and where the trans computer is located? n thanks for the quick reply

[rsiwicki]

tcu is in the drivers side (left foot) kick panel...behind the carpet next to the emergeny brake....don't know what to tell you but the two trans should be a R&R operation....but others are much more experienced on something like this as it maybe something really simple that was overlooked

the 93 TCU is the only TCU with the 1st gear start...the 90-92 TCU's all have 2nd gear start which creates undo stress on the transmission shortening its life so that is why you want the 93 TCU.

[djauto]

what will i need to make the tcu work i already grabbed the computer to which you are referring to... I do know the odometer will probably need to be change to the odometer with the tcu, and ill have to get the tcu switch. any other idea.

[louiegz]

I have 2 q45's a 90 and 93 the 93 is wrecked

Hey, if the engine is good and the guides were done, that might be good for Wes's car. Wes, check this out. If you want to sell your engine, Wes might buy it.

[rsiwicki]

no need to change odometer....it is a simple plug and play for the 90-93 TCU's....

I am put in a 92 transmission into my 95 car and have swapped between a 93 and 95 TCU with no problems for the past 3 months and the gearing is different for the 90-93 transmission vs. my 95 car...you gearing is the same for the 90-93 Q's....

[djauto]

my only question is the 90 doesnt have the tcu so why are all the plugs the same, and also when i removed the trans the 90 trans will click 5 times by moving the linkage for the shifter and the 93 has 4 clicks

[rsiwicki]

don't know...beyond my knowledge, maybe ask Q45tech what's up but as far as I know and have heard...all 90-93 trannies should be relatively the same

[elwesso]

No TCU??? That might explain why it doesnt shift!!!!!!

[djauto]

You tell me am i right? I thought the 1990 model doesnt have a tcu. and the 93 does of course. so what gives ? How do i get the trans to do something.

[rsiwicki]

wow!!! that is a first that I have ever heard that the 90 does not have a TCU

[elwesso]

EVERY Q has a TCU... They are electronically controlledby the TCU... So with no TCU they probably wont do anything (may go into fail safe??)

You need to put the TCU in if you havent already!

[djauto]

all i did was switch the trans from the 93 to the 90. i didnt add or remove anything. the 90 doesnt have a tcu switch (in the middle console) the 91 and above have the tcu button. that is the only difference that i can see.

[djauto]

i was just looking in the q45 portal and it says the 91 traction controll was added so 90 probably didnt have it.

[00_Altima MD]

90-93 transmission's are freely interchangeable (barring the occaisional drivability problem due to slightly different tcu's/ecu's but nothing major)

If it doesnt shift at all one could speculate, its likely a wiring problem, of some kind or a damaged TCU..

[Jesda]

I think we need to clarify some important terms.

TCS = Traction Control SystemTCU = Transmission Control Unit

[rsiwicki]

ahh....here we go. The confusion between the TCS switch and a TCU. You should not need to do anything with the TCS switch as the TCS is not connected to the transmission, rather the TCS is connected to the pumpkin (rear-diff) with sensors on it to determine traction and ABS as well.

btw...you can't easily switch the pumpkin between the 90 vs. 93 as the shaft lengths are different

[djauto]

i changed the computer thats located under the kick plate, their was a different # on it to .. i thought that would do the trick but no such luck.. So im probablly looking at a damaged wire or something like that?

[Q45tech]

I would be concerned that the transmission wasn't mechanical installed correctly.Easy to not get a TC to shaft engagement ant nothing happens same with misaligned shift linkage.

[djauto]

Hello guys by the way thanks for everyones help....

I got under the car again (last night) the shifter doesnt work properly so i disconnected it from the shifter. and manually moved the linkage on the trans through the gears. Im only getting 4 shifts when it should do 5 ..Park is not working. Obvously there is something hooked up wrong. any ideas and hopefully this will be the problem that im encountering with the trans not working at all.