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Old 03-05-2010, 09:15 PM
Wac Wac is offline
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700R4 Double downshift not holding... WHY?

Ok Trans wiz-kids... I had my 700r4 rebuilt recently. Beast sun shell, 5 pinion planetarys, zpack, corvette servo, pump upgrades.

After making sure the TV cable was set up correctly with WOT from pushing the pedal to the floor instead of at the carb, It drives fine, and downshifts one gear fine for passing. No Stacked shifts like would be the case with too loose a cable, and it doesn't downshift too quickly or rev high before up shifting so from all I've read, this is how it is supposed to perform under light to moderate conditions

HOWEVER, If I accellerate slowly, get it in 3 rd and then go WOT it will downshift to 2nd, then quickly to 1st, but not hold it in 1st... it shutters a bunch and power is pitifull eventhough engine is up in RPM. Let off and it stays in 2nd with pretty normal power until upshift is need or I let off the throttle.

Same thing if I get just into 4th-OD, go to WOT it will shift to 3 then 2 but shutter til I let up on it, and it goes back to 3 and keeps pulling with better power.

Something is NOT correct... What's going on??

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Last edited by Wac; 03-05-2010 at 09:50 PM.
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Old 03-06-2010, 05:30 PM
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Quote:
Originally Posted by Wac
Ok Trans wiz-kids... I had my 700r4 rebuilt recently. Beast sun shell, 5 pinion planetarys, zpack, corvette servo, pump upgrades.

After making sure the TV cable was set up correctly with WOT from pushing the pedal to the floor instead of at the carb, It drives fine, and downshifts one gear fine for passing. No Stacked shifts like would be the case with too loose a cable, and it doesn't downshift too quickly or rev high before up shifting so from all I've read, this is how it is supposed to perform under light to moderate conditions

HOWEVER, If I accellerate slowly, get it in 3 rd and then go WOT it will downshift to 2nd, then quickly to 1st, but not hold it in 1st... it shutters a bunch and power is pitifull eventhough engine is up in RPM. Let off and it stays in 2nd with pretty normal power until upshift is need or I let off the throttle.

Same thing if I get just into 4th-OD, go to WOT it will shift to 3 then 2 but shutter til I let up on it, and it goes back to 3 and keeps pulling with better power.

Something is NOT correct... What's going on??
well lets see here, ill give some ideas, since it only shutters on 2 gear downshifts, id think it would be pressure regulator, or maybe a t.v. problem
but, still need more info would be helpful.
have you had a pressure gauge on it?
what kind of vehicle is this trans in? did this vehicle come with a 700r4 or a retro?
is the governor bore ok, is the gear new? does it have a corvette governor? whats been done to the engine and whats the rear gears and tire size?
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Old 03-06-2010, 08:30 PM
Wac Wac is offline
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Quote:
Originally Posted by tnsmith10
have you had a pressure gauge on it?
what kind of vehicle is this trans in? did this vehicle come with a 700r4 or a retro?
is the governor bore ok, is the gear new? does it have a corvette governor? whats been done to the engine and whats the rear gears and tire size?
No pressure gauge yet... but am thinking of getting one for this soon... what is the correct pressures and pressure changes to look for?

'89 Jeep wrangler... all aftermarket; chevy 350 TBI probably 250-300hp, NP231 stock wrangler transfer case, 4.11 gears, 33" tires, ford rear end.
New stock governor with rebuild, not corvette.
TV cable has been a smidge tigher, and a smidge looser. same shuttering on 2 gear down shift. TV cable was set up with bowtie overdrive tv cable bracket/spring kit:

http://www.bowtieoverdrives.com/cata...php?ITEMID=217
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Old 03-07-2010, 07:33 AM
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Quote:
Originally Posted by Wac
No pressure gauge yet... but am thinking of getting one for this soon... what is the correct pressures and pressure changes to look for?

'89 Jeep wrangler... all aftermarket; chevy 350 TBI probably 250-300hp, NP231 stock wrangler transfer case, 4.11 gears, 33" tires, ford rear end.
New stock governor with rebuild, not corvette.
TV cable has been a smidge tigher, and a smidge looser. same shuttering on 2 gear down shift. TV cable was set up with bowtie overdrive tv cable bracket/spring kit:

http://www.bowtieoverdrives.com/cata...php?ITEMID=217
ok, well the pressures you can find here by m&mcustom about 1/2 way down the page here .
what your also going to need to do is buy a governor calibration kit, that will help you dial in the 2 gear downshift and getting it to hold. just offhand, your going to want to go with a heavier spring for part throttle upshifts, and then the lighter weights will control the full throttle upshifts.
once you find where your pressures are at, and if the pressure fluxuates when it shudders, itll help narrow it down to either a pump problem, or something else in the trans. i.e., converter, or forward sprag. since its applied in 1st, 2nd, and 3rd gears that also could be the problem.
have you tried doing a manual shift to see if it chatters that way as well? the overrun clutch will be applied in d down to m1 and with it applied, the shutter may not be there which could idicate the forward sprag as the cause.
once you find the cause of the chatter, and get it fixed, the governor re-calibration kits will get you dialed in on the full throttle early upshifts. gl
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