TF727 Part identification

that is (simply enough) called 'kick-down lever'.

8~)>

WARNING! don't drive without it! TF727's need that lever to control line pressure. it will eat itself rapidly if you drive it without this lever installed. you could, though, pull the pan off the tranny, turn the screw to crank up the line pressure and then drop the valve body, throw all of the springs that come out and put it back together. less need for the kickdown lever after this mod.

-- bob z.

"people with less brain power than you are doing more difficult things everyday"©

It's simply called a kickdown lever. If you don't have it installed, it can and will damage the transmission. The lever activates a rod that compresses a spring in the valve body which controls the pump pressure. The increased pressure is there to apply more pressure to the bands and clutches. It also controls downshifting (passing gear). If you need the lever, you can scour the salvage yards, or possibly check with a transmission shop. We have one here that always has the little hardware parts available. You can also check EBay.

Chris

Yeah, I definately am going to hookup the kickdown. I went to the dealership at lunch and paged through their catalog. I think we found the right one. For $4 I'll know in a few days if it's the one! Otherwise I'll hit up the tranny shops.

I have a '67 Chrysler 300; I've taken the kickdown and wired it to one spot (off, of course). Is this bad? I believe it has the TorqueFlite 727. __ Steve .

yes, this is bad. do you shift this thing manually? if you don't, you probably have noticed that it probably shifts itself through all 3 gears before you are even all the way through an intersection. the kickdown lever controls line pressure - line pressure controls how hard the bands clamp the drums. you don't want the drum to slowly stop from a band just barely clamping it. this generates a lot of heat from friction. heat eats bands and clutches. the optimum duty cycle for an automatic includes instantaneous shifts with no slippage of the bands on the drums. this results in harsh driving conditions, but the transmission will definitely live longer.

'67 Chrysler 300. beautiful car. big block, i presume? yes, it will most definitely be a 727. a 904 wouldn't live for very long behind anything else in that car!

-- bob z. p.s.

"people with less brain power than you are doing more difficult things everyday"©

I had noticed that...

Ok, thanks... I don't drive it much, it sits out there and glares at me. Too expensive to keep legal, and since it's not registered/ insured, I definitely drive it a minimum.

Yes, big is the operative word. It's the two-door, with 350hp 440. A labor of love, bought the thing for $500, got several thousand in it, without repairing the rust (ever seen a vinyl top bubble up? Not pretty...). Still, it's the only hot-rod I got... I should work on it sometime. __ Steve .

If you don't care about the car being original or not, go to

and check out their kickdown cables. They are easy to hook up and they work great. Look good too.

Chris

Thanks for the link... if I did that, then the rest of the car would have to be tricked out to match! If I go the original route, all I have to do is re-connect the linkage, and tune to spec... cheaper, too (it is a *low* budget project). Time to duct-tape the rust holes before the next rain. __ Steve .

Steve,

I didnt realize you had the original linkage.

Chris

Bill,

The first thing I would check with that transmission is that the TV (throttle valve) cable is properly adjusted. The lockup wiring simply locks the converter. It doesn't really do anything else. This is one transmission that is even more critical to have the throttle linkage/cable hooked up than the TF is. The stock 700R will more than like not handle the power of a 426 without some serious modifications, especially if it is a pre 87 model. One other thing about the 700R, if you don't have a decent trans cooler, it won't last long.

You can improve the clutch apply pressures in this transmission with a bigger throttle valve. GM had a police package upgrade for this transmission that included a valve to eliminate the automatic downshift at half throttle, as well as a bigger throttle valve assembly. You can also upgrade to an aftermarket version from

The other main upgrade on this trans is to replace the standard servo with the Corvette model servo. This has advantages and disadvantages. The apply pressure to the 2-4 band is improved, but at the cost of a slower apply rate. To remedy this the apply ports in the valve body plate are increased in size.

If the trans is slipping and the TV cable is adjusted properly, I'm afraid that your clutches are probably already damaged. This was the first transmission I rebuilt for my 350 S10 swap. I used a 1985 model transmission and did all the necessary upgrades. The trans is definitely more involved than a TF but it's not bad if you take your time. There are just a lot more parts in these things than there are in a typical 3 speed auto.

When is the transmission slipping? Does it do it in certain gears or all of them? We can probably narrow down the problem with more info. Also. I still have a list of all the mods I did to my 700R, but I'll have to dig them out for you if you want them. Just let me know.

Chris

How did you adjust the TV cable? It is a quite sensitive adjustment, and as little as 1/8" makes quite a difference. Mine took quite a while to get right. A good starting point is to open the throttle all the way and then adjust all the slack out of the cable. This is usually too much tension on the cable, but it is a safe starting point.

Also, don't get me wrong. The 700R can take a lot of punishment, but it was never designed in stock form for something with the power of a 426 Hemi. The most powerful engine put in front of a stock 700R was the 454 found in the

84 and newer trucks. I believe the SS454 would have been the most powerful one, but I have no idea of the HP or torque that engine puts out. It's not even in the same class as a stock street Hemi, let alone a Hemi that has been modified.

If the trans is slipping in all gears, then the pump is probably not doing it's job, or the TV cable still isn't right. The older 700R pumps were prone to cracking the ring that retains the pump vanes. If this happens, then your pump will lose most of its pressure, which in turn will cause less apply pressure to the clutches and band.

If it is slipping in 2nd and 4th, then the band is gone or the apply servo isn't applying enough pressure to hold it. This could be because of a bad servo seal, or just the fact that you are overpowering it. There are aftermarket servos available, in addition to the Vette one. The nice thing here is that they can be changed from the outside of the case, as long as you can access the servo cover. But like I said, the bigger the piston here, the slower it will shift into both 2nd and 4th gears.

If it is slipping in 3rd and 4th only, then it is more than likely the 3-4 clutch pack, or the apply piston seal. The 3-4 clutch failure is quite common due to the lack of cooling of these clutches. This is because of the transmission design. The clutches are buried inside everything else and are the last thing to get lube, even though they are the ones doing the high load work. The mods for the 3-4 clutch involve drilling extra oiling holes in the clutch drum, as well as upgrading to 2 extra clutch plates and steels in the clutch pack.

BTW, whatever that Hemi is in with 4.56 gears and a 3.06 first gear has got to have one hell of a holeshot. I hope your friend gets this sorted out.

Also one other note. Painless makes a wiring kit for the converter lockup on non computer vehicles with this transmission. It is basically a new solenoid that goes in the valve body, along with a brake switch and a vacuum switch. The kit allows the converter to lockup in 4th gear only, and it automatically unlocks when the vacuum drops below 12" (I believe) and the brake pedal is not depressed. This is the kit I used in my S10 and it works great.

Chris

i am obviously too late with a reply, but it looks like Chris gave you a lot more information than i ever could have. i don't have much experience with chevrolet trasmissions. all of my experience is with chrysler and volkswagen. what a combo!

8~)>

-- bob z.

"people with less brain power than you are doing more difficult things everyday"©

Got it! Ordered it at the Jeep dealership. Cost me $4.68 and works perfect.

So after I scoured a friends garage for it (that's where we stripped out the engine and tranny.... he sees what I ordered and says "oh, that part? It's sitting on the 'other' workbench in my garage". It was at his house the whole time. Oh well, for 4 bucks I think I'll just use the new one (plus the old one is missing the bolt and square nut to hold it to the post). IT NEVER FAILS!