My much anticipated 5 speed swap has began to show its ugly side. The trans I installed was a TII trans with 151k miles and I still have my 3.90 rear diff. My problem is I can't unleash this car because the syncro on 2nd is shot and the 3.90 just sucks off the line. Granny shifting combined with the 3.90 and closed 5th and 6th ports (fixed that) and tires that I swear was coated in crisco I slugged it through the 1/4 in 18 flat (at 4700ft of course). The motor is plenty powerful with a new light flywheel and new TII clutch. I'm going to rebuild this trans so what should I replace to ensure smooth 8k rpm+ shifting and also I need custom bushings for the crossmember because I had to use the auto crossmember and the bushings didn't exactly fit so there aren't any bushings. I'm using royal purple gear oil and the trans holds all gears just fine. 2nd gear syncro is definitly gone and it shudders at 7k+ shifts. A 4.30 rear is in the works and new Toyo's are on the way. Just need advice on rebuilding this trans and with what parts.

 

I've never done it and I don't know of many people who have, other than experienced transmission shops.

 

Even with synthetic gear oil, a red line shift will get ahead of a 151K tranny.
Short shifting to 2nd at around 6K max should help.
With the 3.90 rear you can help your final drive ratio with 50 or 45 profile tires on 15" rims.

 

It seems 2nd is the only gear that has shifting problems. If I double clutch it at 6k it shifts fine but if I slam it at 7800rpm it grinds and the tires spin. The reason I'm concerned is the cars powerband seems to be between 6k-8k rpm. Should I just replace the syncro on 2nd or just replace the whole damn thing. Also I'm running 55's on 16 inch rims.

 

1st gear acceleration is very addictive, so it takes practice nailing 2nd at 6K.
Do you have a g-tech? They are $45 from http://gpsworldsupply.com/gps_world_...oductNum=GTECH
Practice 0-60 runs with the g-tech will tell how you're doing with different techniques.
I still catch myself holding 1st too long.

Next set if tires, drop to maybe 45's

 

Good luck - you're going to need it.
No FC trans is going to handle redline shift from 1st to 2nd.
You're going to kill the synchro or the gear itself if you're going to abuse the trans.
The reason this is not possible is due to the numerical gear ratios of 1st versus 2nd gear.
I tend to short shift 1st into 2nd due to this at 6,500RPM.
The other option is to wait a little longer during the shift, which just slows you down.


-Ted

 

Here is a short video from an autocross.
Launch hard & short shift to 2nd. link to short video

 

So there is no way a TII trans will hold up to 7k rpm 2nd gear shifts? Well how can I mod the trans to run smooth and be able to shift smoothly at 7k+?

 

My na trans takes my 7k shifts from 1-2, but grinds when I take it up to 7.5k.

 

No.
Unless you can find a way to swap out the 1st gears to lower numerically (which I am not aware of such a thing exists), it's not possible.


-Ted

 

I don't know, my 145,000 mile NA trans takes 8k+ shifts from 1st to 2nd. And that ain't no BS, just incase anyone wants to argue that. If I could mount the digital video camera in the car somewhere while I am driving, I would have proof for ya.

 

Reread the original post.
We're talking about TURBO transmissions, NOT NA ones...


-Ted

 

So would it be the differences in gear ratios between the N/A trans and the TII trans that makes the shifting differences? The syncro in 2nd is for sure gone because it grinds at any rpm. So I should probably learn better technique going from 1st to 2nd rather than dumping it at 7500rpm. All I want is a smooth drivetrain dammit!