Disabling 4th gear

[twinv6gtp]

On the 4t65 and 4t80e.

Is it as simple as leaving them in 3 position ?

I want to use an aftermarket shift box on them but it will shift to 4th unless something prevents it.

Click to read more...

 

[jdredd]

My trans has hardware removed to go into 4th. Plus PCM is tuned to never
let it try to shift to 4th either.

 

[Rent Free]

i know people have but whats the purpose of "deleting" 4th in the 1st place and is it worth the effort to do so on anything other than a strip only setup?

 

[1quick]

on a high power car if you let it shift into 4th under full throttle it will break and probably take out your trans

 

[Rent Free]

ok and even with hardened 4th hub still going to destroy 4th on a turbo car or is it worth it to disable/delete it?

 

[1quick]

if your building a street strip car i would keep 4th so its not super anoying when your driving around on the street, I had 4th in my old turbo car and it was fine i never went fast enough to shift into 4th full power, i just going to guess but im thinking you would have to be going around 160 to shift into 4th with a 2.93 gear set, and thats not a speed i would ever want to see in a wbody lol

 

[Rent Free]

awesome thats the kind of info im after thanks.

 

[jdredd]

4th is stupid weak clutch wise. High power build and shifting to this under heavy load rips em up. Just not enough there to work with under any real power.

My first "built" trans as it was billed from guy I bought from, had 700 miles on it before I got it, from a turbo car.
4th was already showing good bit of wear on it.

 

[Turbocharged400sbc]

i know people have but whats the purpose of "deleting" 4th in the 1st place and is it worth the effort to do so on anything other than a strip only setup?

the original reason was for the passage use by the wires for a tooth sensing ISS sensor setup to get rid of the troublesome OEM tone wheel/sensor that breaks off at high power.

the remaining passages were utilized for the feed for the trans brake that the GMR "3 spd" drag transaxles had.

if using the oem pcm trans controls youd be able to tune it out, dunno on your external box...

 

[Turbocharged400sbc]

the TR's trans managment is 4th is a cruise gear, only shifting into it at low throttle %.

depending on yer FDR th isnt really needed untill over 50mph.

its just a mater of training yerself to shift to 4th when your cruising for long enough stretches.

the track only file is set to prevent part throttle upshifts/wot downshifts, 4th delete, etc

 

[jdredd]

the original reason was for the passage use by the wires for a tooth sensing ISS sensor setup to get rid of the troublesome OEM tone wheel/sensor that breaks off at high power.

the remaining passages were utilized for the feed for the trans brake that the GMR "3 spd" drag transaxles had.

if using the oem pcm trans controls youd be able to tune it out, dunno on your external box...

That is what I have also. Worked out pretty well. Need a deal to boost the
signal up for PCM to detect it, but once that was done, no more pesky wheel.

 

[twinv6gtp]

I was thinking of using a GPS switch to make the shifts.
With 1300-1500HP it will be pretty hard to use tire speed or RPM to shift.
An Early shift slows me down and it was happening in the end at higher power level. GPS speed would be the more accurate way to shift. I can also use it for many other purposes...

But I don't want my manual controller to go to 4th. So does staying in "3rd" range prevent any shift into overdrive ?

Is it possible to get the trans in "safe mode" (full line pressure, no 1st, no 4th) and still use solenoids to shift ?

 

[Rent Free]

safe mode sounds like race mode that would be interesting!

 

[twinv6gtp]

Safe mode is what made it possiblr for me to run a very large amount of low 11d and 11.0 runs on a bone trans as a fwd with my parts car gtp. Thats how I ran my stock trans in front of my twin engine making 600hp and no failure as well. No 1 to 2 shift shock load.

 

[OffshoreDrilling]

I was thinking of using a GPS switch to make the shifts.
With 1300-1500HP it will be pretty hard to use tire speed or RPM to shift.
An Early shift slows me down and it was happening in the end at higher power level. GPS speed would be the more accurate way to shift. I can also use it for many other purposes...

But I don't want my manual controller to go to 4th. So does staying in "3rd" range prevent any shift into overdrive ?

Is it possible to get the trans in "safe mode" (full line pressure, no 1st, no 4th) and still use solenoids to shift ?

How quick of a refresh rate does a GPS have though?

 

[twinv6gtp]

I want a 10hz switch.

 

[Turbocharged400sbc]

yeah um safe mode is the oem pcm trans tables.

if you were using the 65e pcm tc youd have no problem programming the shift tables to do that

 

[Turbocharged400sbc]

i believe that manual 3rd does disable 4th but it may not...i dont have a 65e hydrostatic diagram

dave norris would know im sure

 

[twinv6gtp]

Pcm shifting can not use external inputs like a gps signal.