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700r4 wont downshift on WOT repost
I need help on this tranny. 700r4 in chevy 1500 truck. ( not electronicly
shifted) I completely rebuilt it after my son ran it in high water. Now it shifts fine...1st shift around 15 mph on normal accelerate 2nd shift " 30 mph 3rd shift around 50mph. but it will not downshift to passing gear when gas pedal is floored. It downshifts when I stop. It shifts when I change gears on the column. I tried making adjustment to TV cable. Too loose gave soft "slippy" shifts tight gives hard shifts around the speeds stated above. But no change to downshift. I didnt use a gauge to check pressure. I found the governor stuck when I overhauled it. freed it up. what gives? Where should I look? Roy I finally got a chance to put a gauge on it. at idle ~ 62 psi in park and neut at 1000 rpm ~ 70 psi " " " " at 1000 rpm with TV cable disconnected from throttle, pressure rose fairly steady up to over 140 psi (140 was as high as my gauge reads) as I pulled the TV cable out. while driving, pressure also rose steady and leveled out about 82 psi at 55-60 mph. when in overdrive, at 55 mph, I floored the throttle, pressure pegged out my gauge BUT tranny never down shifted. I tried to check pressure as I forced a downshift by shifting into 3rd, from collumn, but the tubing and fitting to the gauge hit the shift lever. I installed a Transtech rebuild kit. I kept all the info just in case I needed to refer to it. I can get you all the shift mod details if you need. Roy --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.809 / Virus Database: 551 - Release Date: 12/9/2004 |
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#2
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I replied to your original post with the paragraph below. Assuming you
didn't see it, here it is again. I also meant to say check the governor, but you already beat me to it this time. If its free and has good smooth seal surfaces and isn't missing any flyweight springs then its probably OK. I remember the servo refered to below better now. It has about 5 or 6 seals on it around the various housings and pistons that comprise the assembly. A lot to go wrong there! --------------------------------------------------------------------- Did you put a different/ updated/ possibly Corvette part numbered 2/4 servo in it during the rebuild? I talked to a trans-guy after I had the same problem with a 700R4 and he suggested that. He sold me one to try. It slipped in without teardown from the pass. side through a steel cover IIRC. Fixed the same problem as you are describing. A pressure check showed a drop when the problem occured and he theorized it was leaking past the servo (its been 10 years, thats the story I'm stickin to) HTH, Toyota MDT in MO |
#3
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This was my first trans overhaul so I dont really know how to adjust things
like the governor. like I said the gov was stuck. It took a while to free it up. I gave thuis truck to my dad so I have to get it from him to test it. I didnt see a pressure drop like you mentioned. It seemed to rise with the TV cable. I can get a 200 pound gauge ,a 90 degree fitting and retest pressures if it will help. I used the same 2/4 servo but some upgrades to the 2nd piston. ground some oil groves in steel cover and a new spring. based on TransGo SK700-Jr-B instructions. Thanks Roy "Comboverfish" > wrote in message oups.com... > I replied to your original post with the paragraph below. Assuming you > didn't see it, here it is again. I also meant to say check the > governor, but you already beat me to it this time. If its free and has > good smooth seal surfaces and isn't missing any flyweight springs then > its probably OK. > I remember the servo refered to below better now. It has about 5 or 6 > seals on it around the various housings and pistons that comprise the > assembly. A lot to go wrong there! > > > --------------------------------------------------------------------- > > Did you put a different/ updated/ possibly Corvette part numbered 2/4 > servo in it during the rebuild? I talked to a trans-guy after I had > the same problem with a 700R4 and he suggested that. He sold me one to > try. > It slipped in without teardown from the pass. side through a steel > cover > IIRC. Fixed the same problem as you are describing. A pressure check > showed a drop when the problem occured and he theorized it was leaking > past the servo (its been 10 years, thats the story I'm stickin to) > HTH, > > > Toyota MDT in MO > --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.809 / Virus Database: 551 - Release Date: 12/9/2004 |
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