700r4 trans problem?

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Post by Hs1973 on Sun Feb 17, 2019 7:04 am

Hi guys. 
Some time ago i put a 700r4 trans in my chevelle. I had a chance to try it out today, i goes into gear just fine and takes of fine. But it wont shift gear at all unless i do it manually. Im guessing the tv cable is to tight and needs adjusting, but can i testdrive it to find the right shiftpoints or what to do. I know its wery importent to have it adjustet right to not hurt the trans so im hasitating driving it to adjust it. I looked on the web but it just makes me more confuesed. I have the correct geometry bracket on the carb and the right cable also the trans worked fine when we took it out of my friends camaro, so i know its problely just adjustment of the cable that is needed. Any advise is welcome. Regards Henrik.
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Post by fasrnur on Sun Feb 17, 2019 12:21 pm

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Post by Hs1973 on Sun Feb 17, 2019 12:45 pm

Thank you. I have been messing with it all day, but i Got sidetracked by what i thought was my starter needing shims, but i could by he life of me not understand why. Then all of the sudden something made hell of a racket and i figured out my radiator scroud had shifter and touching my fan. So i messed around with that and had the starter off  4-5 times. So tomorrow im going to see if i cant get the cable adjustet right. im sure its to tight so im slacking it off a bit and see what it does.

I was just worried if i risked hurting the trans trying to adjust it, but i have read up on it and it seems it is only running it with to much slack that could be a problem. I need to ask my insurence permission to testdrive it, because im not alowed to drive it before march 15. Its a part of the terms of insurance on classic cars here that we are not alowed to drive it during winter. However the wether is fine right now so im have a hard time waiting.
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Post by fasrnur on Sun Feb 17, 2019 2:13 pm

It would be so hard for me to resist not at least driving it around the block once. lol
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Post by 73ss on Sun Feb 17, 2019 9:08 pm

OK, Your trans should still shift even with a tight cable. The shifts will be late and hard. When the cable is too loose, The shifts will be early and soft or stacked, This is where you need to be careful about burning up the trans. The main thing to look for is at WOT, you don't want anymore pull on the TV cable. If you have a factory self adjusting type cable, You cannot get it too tight. It will ratchet or click out if you run out of cable before the pedal is at WOT.

Try running the engine up to temp, Un-hook the TV cable at the carb, and pull it all the way out 10 times or so with the engine idling, this will help clear any dirt that might be in the TV valve. You could also have a stuck, gummed up governor. You can pop that out of the side of the trans without too much trouble. You don't have to drop the pan to do this. It has weights & springs that may be dislodged or stuck.

Was anything done to the trans after it was removed from the other car? Was the pan off? TV linkage inside the pan hooked up correct?

http://www.tvmadeez.com/article/index.php
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Post by Hs1973 on Mon Feb 18, 2019 4:38 am

Nothing has been done with the trans since we took it out, only fluid change. I could not drive it far enough to try it out but it just stayed in 1 gear when i was expecting it to shift. Problem is im not supposed to drive it yet so i only took it up my street wich is not that long, and when it did not shift like i expected it to i just put it back in my garage. I could only  go around 25 miles an hour before running out of Road, and i dident want to go on the main Road without insurence. 

 I test drove it before we took it out and it worked fine, it was rebuild by a prof in USA with a 500 hp upgrade and reinforcement pack, so it should be stronger. It has only seen 5000 miles since rebuild. It shifts when i do it manually. 

Today im of work and im going to try it again without the cable backed of a bit and see what it does. I know a little bit can change alot. And from what i have read it only hurts it if the cable is slacked off to much. 

I report back later when i have messed with it.
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Post by Hs1973 on Mon Feb 18, 2019 7:15 am

Update. It turned out to be the cable adjustet to tight. I backed it of a little and Got it to shift, it took some testing to get it to shift correctly. However im happy with the 1-2 2-3 shift but the last shift into overdrive is not good enough yet. The 3-4 shift is only happening at relativlly High speed and not when i expect it to.

So im looking into how to adjust it or if maybe there is a bit of dirt in the guvernor or air trapped in it. But for now i need to wait until i can drive it legally. Im just happy i Got it to a point where i can drive it. Now i need to go and fix some other little things like a speedo not working and a lockup control box not working. Also its pretty dirty now after driving it on the wet Road, so a wash is in order i guess. Thank you for your help and support.
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Post by thatfnthing on Mon Feb 18, 2019 9:47 am

What size are your rear gears? If they are lower than 3.42, the 3-4 shift (and OD lockup) will occur much later than normal.
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Post by g3chevy on Mon Feb 18, 2019 11:35 am

What carburetor are you running? If its a Quadrajet, are you running a factory bracket for an overdrive transmission? I just replaced the Quadrajet on my 87 SS El Camino with an Edelbrock. It has a factory 200-4R overdrive in it and I had to replace the cable bracket and add a pivot arm to the linkage directly on the carb to get everything adjusted correctly. Here's some pics below. It took several test drives to get it dialed in properly. Going by what TCI suggests, your 1-2 shift should occur around 15-20 MPH, 2-3 25-30 MPH and 3-4 40-45 MPH. Not sure what that is in Kilometers but hopefully this helps. Also I'm running a 3.73 rear end gear and it cruises at 70 MPH at 2,100 RPM.

700r4 trans problem?  20190121
700r4 trans problem?  Edelbr10
700r4 trans problem?  Edlelb10
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Post by Hs1973 on Wed Feb 20, 2019 4:07 pm

I have a 3:23 rear and im running an edelbrock with the correct geometri bracket. It seems like it is shifting correct now. Im still unsure its ok as is, it shifts really Nice 1-2-3 and into 4 when im cruising at a Steady speed. But im not sure its enough just to mess with the cable since just one click makes a difference in how it performs. So im looking into getting a gauge and doing a pressure test or having someone testing it and adjusting it for me. 

Or is it ok just to adjust it by feel until it performs ok, i have sort of a feel for when i expect it to shift, from driving with auto trans Many years. It sort of is imprinted in my head how and when it should shift. So when i drive it i sit and expect the next shift, and if its not coming it feels wrong. 

I know Reading stuff online can make one even more confuesed but i really dont want to burn this trans up from doing it Wrong, cause i dont have the funds to for a rebuild, and i Seam to read everywhere its make or brake getting it right, and the only Way to be sure is a pressure test. Or what do you say? If it feels right just be happy and drive it? Or do i risk burning it by adjusting it by testdrinving it around. Last time i tested i drove it up and Down the same Road like 10 times, adjusting it one click at a time from fast stagged shifts, to Nice shifts at the right speeds. If that is not the Way to do it, i dont want to push my luck anymore. However finding someone that koows how to pressure test it is not easy here.
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Post by g3chevy on Wed Feb 20, 2019 5:17 pm

Yes, you can test drive your vehicle and adjust the TV cable by how it performs. One click at a time per test drive will get you where you need to be. As long as there is tension on the TV cable at idle, you shouldn't have any issues burning up your transmission. Mine is pulled out roughly a half an inch at idle and it shifts just like described above in TCI's literature. The only concern I would have is that your have a rear end gear that is not optimal for an overdrive transmission. Most of the stuff I've read indicates you would want at least a 3.42 rear gear or numerically higher to properly utilize the 4th gear in your transmission.
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Post by 73ss on Wed Feb 20, 2019 7:02 pm

700r4 trans problem?  20190110

Have someone hold pedal to floor, Take some pliers try to pull on cable end. (red arrow). If you can pull it out more than 1/16", tighten it up a click. Much more than 1/16" pull will slowly wear away at trans. TV valve needs to be fully depressed at WOT. One click is approx 1/32"
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Post by thatfnthing on Thu Feb 21, 2019 10:34 am

3:23 is a tad low, which in turn will mean the car is moving faster than the trans thinks it is, and the upper shifts will come in later.  I first ran my 200-4R with the original 2:73 gears for a couple weeks before I could get them swapped out, and my gears were so tall that when the trans would make the shift, the RPMs would drop back down almost to idle.  This meant I was below the engine's power band, and the engine lugged trying to build the RPM's back up.

Once I swapped to a 3:42 in the rear, the RPM's fell in line, the shifts stayed in the power band, and OD and converter lockup were all in by 45 MPH.  If I'd gone to a 3:73 or higher, my launches would be even better, but I wanted to keep the highway cruising RPM's in the 1700-1800 range.

You're right, there's a ton of info out there on how to adjust the TV cable, but in the end it all boiled down to making sure the cable is fully extended when the engine is at WOT.  Everything else is secondary.  The whole point was to make sure the trans pressure was high (cable extended) when you step on it.  If the pressure is low, that's when you run the risk of the trans eating itself.  An alternative is to have a high-pressure valve body installed in the trans, so it runs high pressure all the time.  I had mine built that way, but I put a pressure gauge on it just to be sure and it's always been good.
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Post by Hs1973 on Sat Feb 23, 2019 9:22 am

First of i must tell you all that you are the most helpfull bunch of guys i have ever meet online. I know my rear is not optimal but i dont have the funds at this point to change it, but its on the list of future upgrades.

I must confess to you that i always have been unsure about doing mechanical work, i can of course do brakes and such but building an engine is not my thing. So every time my stuff dont work right, i lay Awake thinking about it and i get upset until its fixed. I dont have alot of cash to burn on my cars so i am always a little afraid it going to be expensive. And i cant leave it alone until it works again.

I Got it working like it should and it shifts perfect now, and i now understand why the 4 gear is coming in a little later than i expect. I guessed it to be something like the rear gear. Im going to continue adjusting it when i can drive it legally next month.

The last thing Wrong with it is my speedo no longer work. I tested it and the cable and speedo inside works fine, but it seem like the problem is in the trans. I have had the speedo housing of and everything looks ok, changed the drive gear still dont work??? I see the aksel turn in the housing with the cable off turning the driveshaft by hand, but its the cable connected nothing. 

Im wondering if its the right housing and gear i have, its what the trans Came with but someone could have put the Wrong parts in it. Is there different housings or gears for a 700r4??? I simple cant understand why it wont turn the cable when it seems the gear is turning??? I need to research it to see what the problem is. And again Thank you for all your help.
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Post by bigredlaguna on Sat Feb 23, 2019 3:46 pm

Just to clarify, the speedometer cable is good- correct? It could be broken or the ends worn enough so their isn't good engagement.

The parts the cable goes into should have a square hole. The end of the cable should also be square. Sometimes the cable rounds off because of resistance in the cable due to wear or lack of lubrication.
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Post by Hs1973 on Sun Feb 24, 2019 2:47 am

I just used a full saturday messing with the chevelle. I established that the speedo and cable works fine, the needle bounces around when i turn the cable by hand. He cable is in good order with no round edges. So i took the speedo gear out of the trans, it looked ok at first. But the gear itself was worn on the middle, so i Found another that was better. I can see tihe shaft where the cable inserts turn when i turn the driveshaft. But when the cable is mounted nothing happens. So im pretty sure its worn inside on the shaft. So i will order 2 new gears and hope it will fix it. 
So now i need to figure out what gear to order to make the speedo correct, i figure i Might as Well do it right. There is a page online where you can Enter your data and it will calculate it for you. However it is in inches wich is difficult for me to use. So i need to measure my rear wheel and recalculate in inches. Hot rodding is not easy, i sometime wish i was into stamps or model trains LOL.

Once again thank you all for your help. Im sure i will be back sooner than later. Henrik.
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Post by bigredlaguna on Sun Feb 24, 2019 3:53 am

A bouncy needle is usually an indication of a worn cable. It is catching and releasing somewhere inside. Sometimes getting some more lube in it will prolong its life, but it is just as easy to replace it with a new one. The resistance that causes the bounce is probably what wore out the inside of the gear shaft.

If you can see the gear on the output shaft of the transmission, the color will tell you how many teeth it has. An internet search will get you that information.

You might be able to save yourself some math headache (if you want) by getting the rpm (revolutions per mile) of the tire size you have. Then just multiply by 60, then by your axle gear ratio to get your driveshaft speed @ 60 mph. Then use either a fraction formula or a % formula to figure out how many teeth the driven gear needs to get 1000 rpm for the cable speed.

You will be dead on or within a mph or two due to manufacture variance on tire size.
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Post by Hs1973 on Sun Feb 24, 2019 9:47 am

I Got the speedo working now, but you are right it bounces a little just when the needle starts moving. Im going to replace the cable along with the gears, as soon as i have calculated what teeth i need. Fortunatly here we have automatic speed warning boxes at the side of Many bigger roads, wich tells you how fast you are going and warns you if you are close to a speeding ticket. So it is easy to see how accurate your speedo is. 
So if its close, i just need a little more or fewer teeth. I read somewhere that 1 tooth is 2 miles an hour, i need to look it up t be sure. I look forward to get it out on the Road when the season starts March 15. I just hope we get good weather this year. It is like missing a loved one not Being able to drive her. It makes the winter seem much longer. I need to get it on the lift at work to weld an exhaust leak.
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