Z32 tt auto questions

[elks240]

Hello all, I am new to the forum but I have been lurking around for a while. Any way let's get down to it with a little history on the car.

 

I have a 93 240sx with 60-1 turbo set up running around 24psi, tt auto tranny (with shift kit installed in valve body), PI 5500 stall converter, q45 rear end with (3.54's), on 26X10.5 drag radials this is mostly a strip car with some street driving.

 

I am having horrible issues with the car not wanting to go into 2nd gear with out bouncing off of the rev limiter. When I had the stock 240sx transmission computer running the tranny it wouldn't shift whether I had it it manual shift mode or auto shift mode. I disconnected the dropping resistor and that seemed to give me a little more line pressure on the low throttle settings ( shifted harder ) but nothing changed full throttle. Now I have done away with the trans computer completely and using switches to shift, so it should shift when I give power in the right sequence to shift solenoids A and B. I am still having the same issue not wanting to shift. So then I thought maybe if I added 12 volts to the line pressure solenoid it would give more line pressure, again nothing changed.

 

My thought is that if you give power to the shift solenoids it should shift pretty much when it is supposed to. So I need to know the theory of operation with this tranny. I have been searching my FSM and this forum and others and coming up empty handed. Any advice or anything you could do to help would be greatly appreciated.

 

Thanks, John

[elks240]

Well today I set up my wifes car on the switches and hers shifted perfectly. So I have come to the conclusion that the shift kit install was messed up. I am going to go get another stock transmission and put it in and see what happens.

[BRAAP]

Let us know what you find out.

 

By the way, would you mind sharing more details of both cars, yours and your wifes, and possibly some time slips for us to drool over?

[elks240]

Well, my wifes car is basically a stock auto 240sx with a few minor things I made for it. My car's best time so far has been 11.9 @120 with a 1.7 60'( 5speed) with a stock block KA24de and with the auto 12.5 @116 with a 2.5 60'. I have been working the bugs out for quite sometime now. But things are looking good I just about have them all nailed. I started my rear brake upgrade last night, figured out the shifting problem ( I hope) I will have the new tranny in by the end of the week. The car would never launch right since I couldn't build boost on the line with the foot/e-brake. I had the stock welded 4.08 gears in it at the time, but since I put the Q45 diff and axles in I am brake boosting about 10psi and close to 4000 rpm's. Hopefully with the bigger brakes in the back I may be able to get closer 5000-6000 rpm's and 15-20psi of boost. I will keep you updated on what I figure out. Here is a video of my car running last year. I haven't seen the track once this year. But I am hoping to be in Houston for the IFO in January. My car looks totally different now then it did in this video.

 

The car in the right lane is mine Left lane is my buddies.

http://videos.streetfire.net/video/7e8bc2fe-6462-4225-9741-14ba505e8762.htm

[Clifton]

I don't know if you can on those but have you thought about using a trans brake on it?

[elks240]

Yes the transbrake was supposed to happen over the summer. I was in touch with a well known ford tranny company who was building a 32tt auto (3A) as well as the 240sx (1A) transmissions. They had the 1A dyno tested out to 800HP and the 3A tested out to 1400HP both manual valve body with trans brakes. I was supposed to be testing the first prototype of the 1A version since my car isn't going to make over 600 for a little while. But that company flaked out on me back in July. I am pretty sure they were the only ones who had a working manual valve body with transbrake for the z32tt. But I hate them guys now and won't buy one from them if and when they become available.

 

So Basically I had the car ready to go this summer but had to go back to the drawing boards.

[Bernardd]

have you tried turning on the first gear solenoid, then turning on the reverse solenoid at the same time? that's all a transbrake does anyway. what about brake boosting in second then dropping it into low to launch? i do that with my old school jatco and it really loves it. lol

[Clifton]

I've read that the Q45 and TT autos are the same. Know if that is true. If some can build one to 800+ HP I would think or hope it could take the same in torque which is more important. Know anyone else that can build the Nissan autos? How much did that company that flaked want to build one up?

[datsun79z]

Elks240;

 

I feel your pains. I too, have a car (n/a 85 Subaru gl) that exhibits downshifting problems. No matter how hard I try I just can't downshift into 1st gear unless I am traveling at less than 20mph.

[elks240]

have you tried turning on the first gear solenoid, then turning on the reverse solenoid at the same time? that's all a transbrake does anyway. what about brake boosting in second then dropping it into low to launch? i do that with my old school jatco and it really loves it. lol

 

Thought about that, but what you would have to do is run a hydraulic line from reverse to 1st. That is how it is inside the valve body. That is how they get the transbrake. And I really don't feel like messing up the tranny. The brakes are almost done and I am going to go get the tranny tomorrow.

 

The company wasn't using nissan internals they were using subaru and I believe ford parts.

 

Yes, the Q45 shared the same tranny as the Z32tt from 90-94, but after that it is like a R501something or other not sure on the rest of the numbers and it does look a little different. And I am not sure what the cost was going to be I never asked. It was supposed to come to me for free to do a bunch of testing with and a discount price when I bought one. But I am sure it would probably be in the 2k range. But these 3A trannies ( Z32TT ) will hold about 650 in stock form before they start to slip in a car that weighs 2700 with driver.

 

As far as not being able to down shift I have no problem with it. My problem is up shifting.

 

Well I have a long day ahead of me tomorrow. Gotta get some sleep. Thanks for the input , keep it up.

[elks240]

Ok well I went to the shop tonight and was going to swap out the trannies. Well I found out that the input shafts are different lengths as well as the pump shaft. So I swapped out the input shafts but I noticed a crack in the pump on my old tranny. So I took it apart and it was in several pieces. Tonight was a whole lot of trial and error I would find one problem then mess with it then find another and another etc... This has taken place over the last 8-9 hours minus 1 margarita that I am sipping on now.

 

 

So tomorrow morning I will go back and see if the pump gears will interchange and move on. Wish me luck

 

But all you would have to do is swap pump housings and input shafts and the Z32 TT and Q45 would be the same. Now I did see one that looked exactly like the TT but I am not sure what the pump housings and input shafts are like on that one. I will find out and post that up as well. ( My friend got that tranny).

[elks240]

I got to drive it Saturday night, and the tranny shifted perfectly. It took about 500rpms between when I flip the switch and when it shifts and it shifts very smooth and solid not as hard as I thought it would. I didn't take it to 3rd gear because I was on the street but that should shift just fine as well. BUT Sunday when I was playing with boost levels I was running around 30 PSI and looked down to see no oil pressure . Now I have a little rod knock. And the turbo has a little bit more slop in it than I want to see, but it isn't rubbing the housing so I have my fingers crossed it is okay. I don't have the extra money to build the bottom end back up and buy a new turbo. So tomorrow I will finish pulling the motor and within the next month I will have another bottom end built and be on the track about the time it opens. Go figure my new brake rotors finally got here today as well. I will keep you posted.

[elks240]

Today I installed another race motor I am buying from a friend who is putting a VG30DET in his car.This motor has made 725whp all ready so I know it will hold my smaller 600ish. But since I was down and the turbo was shot I am getting a new turbo and will make an exhaust manifold to mount it on. But since I was waiting I made a new intake manifold ( I had all ready started this a while back but never finished it till now ). Here are a few pics of it.