G50 Late shifting

[66mgb]

I've noticed that my G50 shift points changed (lagging) after my 18" tire installation. I'm assuming that the difference in tire diameter is causing this.Is there a module that can be changed to coincide w/ my alterations?I've read that when you changed to the 4.08 gears, there was something that you could replace.I still want to keep my stock gearing for now, but thought that the transmission needs to shift at the proper rpm for a long service life.

I know the easy answer is to go back to a stock tire diameter, but those G35 wheels look so damn hot!

BTW, I'm due for my annual transmission flush and filter. Might be a good time to make changes then. (if possible)

(edit)Also to throw a wrench into the sprocket so to speak - I'm also installing a '93 TCU in my '92. I know that it has 1st gear start, but not sure on the shift points.

[maxnix]

Tire size shouldn't make that much difference as most difference in diameter would be <5%.

1993 is programmed for your 1st and 2nd gear ratios. Later ones are preferred to earlier, but I don't quite remember why.

[CrimsonQ]

Thats weird. Ive never had that problem after switching mine to G35 wheels.

Is it hanging thru all gears?

On the tcu if I recall correctly, the earlier 93 tcu will cause a slight over rev? so to speak in first gear. I noticed mine held on for a split second more after I put in the early 93 tcu. Hasnt seemed to be a problem since, but my car rarely sees redline work too.

Good luck bro, I also have a stock 90 (2md gea start) TCU lying around. Just incase you want to try a different one out. Let me know. Its free + shipping

[elwesso]

what tire size are you running? What TCU are you running?

[66mgb]

225/45 R18 - 245/45 R18 Pilot Sports ...need Z rated rubber soon... My '92 looks exactly like CrimsonQ's only in white.

Stock '92 TCU

Lag is in all gears - I would say that you have to go 10mph faster to reach the next shift.

Maybe wheel sensor is bad or something in the transmission, i.e.: low line pressure??

Would diagnostics show any problems? I might take it to the local Nissan dealer (to get cornholed) and see what they could find.

[66mgb]

Ok - now I'm red faced right now!

Checked my transmission fluid level - of course it was low, since I just installed the transmission cooler and forgot to add a quart.

Topped off the fluid and installed my '93 TCU - now I can't stop smiling!

I'm still going to do a flush and filter.

Of course now because of the 1st gear start, this will lead to a torque converter, driveshaft and differential failure!

[elwesso]

actually hte 1st gear start is a lot easier on the TC and everything else..

The pilot sports should be Z rated... Just put 245-45s in the front and call it a day.

[66mgb]

Ok now I'm getting worried - took it out on the interstate and jumped up to 90 mph.

After about 5 min. the transmission felt like it jumped into neutral (engine rpm's went up - no power to rearend) After I backed off, it jumped back into gear.

Bad solenoid or is the torque converter giving up?

[elwesso]

hmm. you didnt feel any weird vibration.. Generally they start making a nasty vibrations when they start slipping..

Only thing you could do is hook a consult to it and see if its electrical, else its new trans time.

[66mgb]

No - didn't vibrate at all - just slipped out of gear when I loaded it up. When I let up it came right back.

I'm curious what it would cost to locate a used transmission and have it rebuilt w/ all of the performance goodies.

[elwesso]

That seems kinda odd, generally when the TC slips it makes nasty noises... Mine slips a tiny bit and you KNOW it when it does it.

[66mgb]

That seems kinda odd, generally when the TC slips it makes nasty noises... Mine slips a tiny bit and you KNOW it when it does it.

Maybe it's just a bad solenoid. The transmission has almost 200k on it, and only God knows how the previous owner treated it, (but I have a clue...) I'm leaning towards Level Ten for the performance parts.

Wes did you take your Q to Level Ten or did you just order the parts? (valve body, converter, clutch packs, etc.)