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Discussion Starter #1
Hi,
I have finally a working 700r4 after three rebuilds and am now setting up the TV cable.
I know all about the WOT throttle setting etc. and I tracked down a TCI corrector bracket 376715 which is supposed to give the proper pressure lift from the start etc. The cable mount is about an inch from the centre of the throttle etc. (can't remember the exact measurement now) Fitted to a Summit four barrel (a type of Holley apparently) The original bracket they sent me did work the TV cable from stop to WOT but it didn't fit the criteria of the distance to the throttle centre.
The problem...
I can achieve full TV movement at WOT i.e. the cable is tight however when it returns to the no throttle position the attached pressure gauge shows 80psi. When the cable is unclipped it drops to 65psi. I have read many articles that say the drop should only be a few psi and that this means long spring syndrome, which is better than short spring syndrome so that's something. I have two springs one that gives 90psi at the start and one gives 80psi but nowhere can I find anyone that sells shorter springs, which I think will give me the extra TV cable travel that I need. The spring I am talking about is in the TV valve in the box itself, I have already upgraded the first part of the valve ( the plunger bit ) to a sonnax one which is supposed to stop downshifting from overdrive all the time and came with a spring( the 90psi slightly longer one). Tried talking to Sonnax about how to set up their bracket with different springs ... they didn't know... great eh?
The box is behaving ok and passed all the shifting tests although shifts at 3000 rpm when floored but that can be adjusted with the governor later if needs be. On an incline at a certain revs it shuttles between 3rd and 4th, rev it a bit and it shifts down to third and holds better. I think if I could correct the TV start position it might fix this problem.
SO the question..
Has anyone adjusted the length of these springs by cutting them down etc or do you know where to buy shorter ones or infact does anyone bother?
I have had so much trouble with this box that I would like to finally sort it. and I don't want to jump in and start cutting springs before I asked if anyone has done it and how much to cut or just trial and error.
On the plus side I am on the road again after two years faffing about! (I did sort many other bits in that time too)
Thanks for any replies
Norm
 

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I would go purely by pressure. 80 at idle seems ok to me especially if it jumps to 150-180 in reverse and forward gears.
Lock up convertor wired or not?
 

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Discussion Starter #3
Thanks for the reply.
Lock up is wired with a kit and a vacuum switch, I think it was a TCI part but bought it a couple of years ago. It selects overdrive at very slow speeds maybe 30 mph, good for economy i suppose, but does kick down when called for. Lockup disengages when I touch the brakes etc.
This is my third rebuild (total miles less than 100miles!) hence a bit twitchy to make sure it is correct. ha
I agree that 80 sound ok but disconnect the tv cable and this drops to 65. According to the TCi or was it Bowtie website that any drop more than 2 - 3 psi indicates long spring syndrome. It passes all the tests but still shuttles between 3rd and 4th on an incline at a certain throttle. This is what it did the last time on a steep hill just before it went bang so you see my concern.
I have not tried that hill again yet...
 

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Hey Norm,
Understand your frustration with these boxes. I rebuild them for a living and no two seem to be the same, and they all come in wrecked !
I wouldn't worry too much about that intial pressure or the slight drop when disconnected. The most important thing is that the moment throttle is applied you get that quick rise to a high level. If the intial pressure is in the ball park, and you have a fully buried plunger at WOT, everything should be fine. Pressures are going to vary from the charts simply on pump variations, idle speed, oil temp ect. Take them as a guide and not as gospel.
I always fit the Transgo Shift correction kit SK700 to all my builds as this contains a few mods to eliminate the shuttling and fit TV correction springs. Its basically good insurance for a trouble free build. Did you fit one in yours? If you get stuck and you want a chat then PM me or give me a call via my website.
Cheers
Jon
 
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