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Off roading Torqueflight Questions (transbrake, tirespin) #2548807
09/11/18 02:54 PM
09/11/18 02:54 PM
Joined: Oct 2004
Posts: 132
Colorado Springs
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Bens_Coronets Offline OP
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Bens_Coronets  Offline OP
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Joined: Oct 2004
Posts: 132
Colorado Springs
I'm building a '77 Ramcharger with a 440, 727, 203/205 doubler, dana 60s and 40" tires. I've got a couple questions that are 727 transmission specific and kinda taylored a little for the CRT reverse manual valve body, since that's what's at the top of my shortlist for transmission upgrades. I'll PM CRT, but thought this'd be best discussed in this sub-forum.

Q1; Can I sit on a hill at idle with a 727 transbrake engaged for several minutes.

Reason I'd like to do this is when I set it in park it'll roll down hill a little to take up slack in the drive train. Then getting it out of park is a bit of a bang as it releases the spring in the drivetrain. The transbrake would do the same thing, but it seems to me it could 'handle' it a lot better. That is, if it does not build up heat or have some other issue with idling locked up for a few minutes. I'm aware if the engine dies, the truck rolls down hill. I'd only be planning to do this if I'm in it.

Q2; With a full-manual valve body the pressure regulator is fixed at high pressure. Does this force me to accept harsh shifts, or can I soften the shifts some (not stock soft, but not 'bang'). I currently shift an automatic valve body manually, but if I leave it in 2 or D and let it shift while I'm in 4:1 low range that 1-2 shift is a pretty hard shock on the drivetrain. The manual valve body would make it predictable, but I'd also like to have the option to make is a little less harsh than my buddy's drag car.

Q3; Burnouts in first gear in water are bad... and some posts elude to finishing a burn out on dry pavement in first gear may also be bad for a torqueflight.... But I've never seen a real answer to why. why/what-for and would this translate to an issue if I'm really working-it on a rock ledge ect and suddenly back off the throttle in first gear.

Thanks,
Ben

Re: Off roading Torqueflight Questions (transbrake, tirespin) [Re: Bens_Coronets] #2548819
09/11/18 03:20 PM
09/11/18 03:20 PM
Joined: Jan 2003
Posts: 25,618
Rio Linda, CA
John_Kunkel Offline
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John_Kunkel  Offline
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Joined: Jan 2003
Posts: 25,618
Rio Linda, CA
1) Solution is to set the parking brake before shifting to Park. As suspected, continued engagement of the brake might overheat the solenoid; John Cope will be the one to confirm/deny that.

2) Most manual VB's can have the stock throttle pressure operate the same as an automatic (instead of pinned wide open) so the firmness of the shifts are dependent on throttle position.

3) Burnouts in 1st gear are dependent on whether the VB has LBA in manual low. The why is because, without LBA, all of the load is on the sprag which is failure prone when abused. With LBA the load is shared with the band so the sprag is less failure prone.


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Re: Off roading Torqueflight Questions (transbrake, tirespin) [Re: Bens_Coronets] #2552287
09/20/18 01:01 PM
09/20/18 01:01 PM
Joined: Jan 2003
Posts: 2,771
Cedar Lake IN
CRT Offline
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CRT  Offline
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Joined: Jan 2003
Posts: 2,771
Cedar Lake IN
1. yes you will burn up a solenoid, you would never use a trans brake valve body on a rock crawler any way.

2. harsh shifts on a manual valve body can be softer by running the accumulator spring and not a blocker rod. One hole must be drilled
in the plate for this to work. tell me when ordering

3. what JK said

Re: Off roading Torqueflight Questions (transbrake, tirespin) [Re: CRT] #2552440
09/20/18 06:54 PM
09/20/18 06:54 PM
Joined: Oct 2004
Posts: 132
Colorado Springs
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Bens_Coronets Offline OP
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Bens_Coronets  Offline OP
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Posts: 132
Colorado Springs
Perfect, thanks.

Now to save up some $$$

-Ben







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