Author Topic: Manula to Auto questions  (Read 5395 times)

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Offline demonx

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Manula to Auto questions
« on: September 24, 2010, 11:37:30 AM »
Car = 1970

I've read a few of the posts in this section and I see people reccomend the TH400 and TH700 boxes for a conversion, but I have a few extra questions I did not notice the answers to.

Does going from a muncie to a auto require any crossmember changes? Are there any high performance auto's that are a direct replacement without crossmember changes or driveshaft alterations?

Does it require that the shift console be replaced to an auto as I was thinking of using the manual shift console and leather shift boot even though it was auto but I'm not sure if it would allow full movement. I plan on having an auto thats got a full manual shift kit.

Does the hole in the floor and everything else line up for the shifter?

What else do I need to consider?


Offline sirfixalot

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Manula to Auto questions
« Reply #1 on: September 24, 2010, 04:24:28 PM »
Have a look at tciauto.com  site  technical resources should answer a lot of questions has dimensions for different boxes & gear to strenghten box.
Auto shifters usually mount to floor not gear box so can be positioned wherever required.
Manual corvette chassis  has a fixed crossmember for gearbox. Auto chassis has a removable crossmember.

Offline Scott

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Manula to Auto questions
« Reply #2 on: September 24, 2010, 05:06:51 PM »
Auto's run fluid through the radiator for cooling, so different radiator.
Autos need the kick down set-up installed on the carby.
May need a different tailshaft.
Not sure if the cross member needs modification.  Perhaps check digital corvette or corvette forum.
Will requiring re-wiring so that the car won't start whilst in gear.  I have bypassed this going from auto to manual, but I'm not sure how it works going the other way.

T400 (and T350) are a mechanical (non computer) 3 speed box.  Both are fairly tough, and are stronger than the T700.

A T700 is also referred to as a 4L60 or 4L60E. E = electronic

The T700 is a 4 speed box and was used in commondores and C4 vettes.  VN's used a non-computer controlled version.  Later commodores and C4's used an electronic version.  T700's have a lock-up torque converter which can be tricky to incorporate, depending on who you ask.  I can't remember exactly, but if you don't do it right top gear will burn out or break.  A T700 will require modification to the cross member to make it fit.

A T700 will struggle to last behind a 502 rat :)

I may have researched this subject previously :hammer:


Offline demonx

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« Reply #3 on: September 24, 2010, 11:22:13 PM »
I was talking to a guy at work about this tonight and he suggested I dog box the Muncie and install a verticle gate. I may have to research what is involved in this and how practicle/streetable/durable it is and compare it to the auto option.

Offline gtc

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Manula to Auto questions
« Reply #4 on: September 25, 2010, 12:33:47 AM »
Quote from: demonx link=topic=7828.msg1045937852#msg1045937852
I was talking to a guy at work about this tonight and he suggested I dog box the Muncie and install a verticle gate. I may have to research what is involved in this and how practicle/streetable/durable it is and compare it to the auto option.


What's your objective?

Don't like clutches?
It's C3 chromie for me, see? Si!

Offline demonx

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Manula to Auto questions
« Reply #5 on: September 25, 2010, 01:44:10 AM »
Quote from: gtc link=topic=7828.msg1045937853#msg1045937853
Quote from: demonx link=topic=7828.msg1045937852#msg1045937852
I was talking to a guy at work about this tonight and he suggested I dog box the Muncie and install a verticle gate. I may have to research what is involved in this and how practicle/streetable/durable it is and compare it to the auto option.


What's your objective?

Don't like clutches?


It's been about 15 years since I had a manual - I've become lazy!

So yes. However since I bought my HQ ute which has a powerglide with a manual shift kit, I've become a fan of the setup. I'd just like more gears on the vette for long trips etc.

Offline mick

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Manula to Auto questions
« Reply #6 on: September 26, 2010, 04:35:20 PM »
Get a Keisler 5 speed, dont get a Auto(IMO).


http://keislerauto.com/

A guy thats coming to a car show i host has put one in his vette, Ill let you know if he is happy with it.


Offline 87Z51

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Manula to Auto questions
« Reply #7 on: September 26, 2010, 07:05:01 PM »
Quote from: Scott link=topic=7828.msg1045937848#msg1045937848

Will requiring re-wiring so that the car won't start whilst in gear.  I have bypassed this going from auto to manual, but I'm not sure how it works going the other way.

Stock and aftermarket shifters have provision for the neutral start switch
Quote from: Scott link=topic=7828.msg1045937848#msg1045937848
T700's have a lock-up torque converter which can be tricky to incorporate, depending on who you ask.

As simple as having a manual switch to operate the lockup or installing a different switch in trans so it locks up automatically whenever in 4th gear (O/d )

Quote from: Scott link=topic=7828.msg1045937848#msg1045937848
I can't remember exactly, but if you don't do it right top gear will burn out or break.

Pre '88 T700's (27 spline input shafts ) only have full flow to the trans cooler when convertor locked.
Running these without lockup can lead to trans overheating.
On later models; running without lockup is no different than running a TH400 where you have a certain % slippage with a non locking convertor

Offline 87Z51

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Manula to Auto questions
« Reply #8 on: September 26, 2010, 07:22:00 PM »
Quote from: demonx link=topic=7828.msg1045937854#msg1045937854
I'd just like more gears on the vette for long trips etc.

T700 Pros
Low 1st gear
T700 with 3.08 rear gives equiv of TH400 w/3.73's  (23% more torque )
With 3.5 rear equiv to TH400 w/ 4.11's

With 3.08 rear ,T700 .70 4th (O/d ) gives equiv of TH400 with 2.16 rear; great for cruising economy
Best of both worlds

Cons.
T700 is p#iss weak in stock form. May break if you look at it
Can be built but will cost.
I have had one behind my 410RWHP 383 for 4 years but it cost me $3500 plus core back then