Should I do a trans band adjustment myself on a 1970 300 727?

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Transmissions have freaked me out ever since I was 16yrs old and tried fixing one on a trashed 1967 Olds Demont 88. After about a year, I never got it back together and junked the car. I've been restoring a 1970 300 Hurst I got from a junkyard in 2001. I put about 500 miles per yr on it. Trans probably is original and has 150K on it. When I got it running in 2003, I replaced all the fluids/filters and was surprised trans doesn't leak, especially for sitting in a field for 10yrs. The only problems I have with it are minor. If it sits for more than 2 days, I have to rev it up to about 2000 rpm for about 5 seconds for it to move in reverse. After that, reverse is fine unless it sits for more than 2 days. It shifts fine except it'll usually stay in second gear for what I think is too long, when I'm driving 35mph. I usually speed up to 40 so it shifts into 3rd gear, then slow down. If I stomp on it, it won't downshift the first time, but it usually will after that. I've played with the downshift linkage but didn't help. There's been no weird noises or any vibrating. I used ATF+4. Years later I tried adding Lucas trans slip but I didn't use too much since I was afraid. There was no difference. If I adjust the bands (tighten til snug, then back off 7 turns on both bands), will these problems go away? If not, how many turns should I adjust? Since its been almost 20yrs (10K miles) since last trans fluid change, This time, I'd like to try mostly ATF+4, 1 bottle of Type F and half bottle of the Lucas...yes all bottles not opened but 20yrs old). I believe all of these are compatible. Mistake or OK? Thanks
 

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No the problems won’t go away. That trans doesn’t have a part throttle kickdown so it won’t ever work like a GM or ford trans on kickdown.

if you back it off 7 turns that is way to much! It is 2 turns, or 2.5 depending on year Of trans.

please stop revving it in reverse. When you start it up put in on N for 15 seconds then it will go right into gear, that’s because N is where a TF circulates the fluid. That’s why you check the level in N.
 

CBODY67

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For the older TFs, the issues you mentioned after re-starting after sitting is completely normal for a TF which does not have its orig atf in it. The cars did not do that when new, or before the first trans service, as the OEM factory fill fluid was allegedly a multi-vis fluid. Once gone, the delayed engagement started to happen. But we didn't noticed that much back then as we were driving the cars every day.

Yet our '66 Newport 383 2bbl would do it on the first start of the day. Starting the engine in "N" gets things flowing sooner and better, too. Just a quirk of the Chrysler 727 transmission.

Apparently, the "converter drain-back valve" lets fluid seep overnight, whereas the ones on Ford and GM automatics must seal better, apparently.

LEARN the idiosyncracies of Chrysler products and you'll have fun and expand your knowledge base.

Enjoy!
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Just to echo the above replies, my '68 Chrysler transmission works pretty much the same as yours, always did. One thing I will add--I've heard ATF+4 isn't compatible with the old Dexron fluid, so shouldn't be mixed. And I wouldn't mix ATF+4 with Type F either. Just use the ATF+4 but make sure to get all the old Dexron fluid out of it.
 
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I guess I should have learned this stuff 20yrs ago, but I'm lazy and just another backyard mechanic. From now on I'll put it in N first. OK, I'll just use ATF4+. I'm not going to adjust the bands and I don't trust todays computer mechanics, so I'll just live with it not going into 3rd on time and not kicking down into lower gear everytime I floor it. I've been asking a number of mechanics and it sounds like no one really knows how to adjust the bands, so adjusting the bands will just take a lot of testing, readjusting and playing around with it...which means I would probably end up breaking something.

Anyone know what this is circled and what is does? (See pic). I thought it was the kickdown linkage but 413 says no. Thanks for everyones response. It really helps.
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I'm pretty sure that IS the kick down linkage. It shifts it into "passing gear" (2nd), but only at WOT. Chrysler didn't have part-throttle kick-down until around '73. But, the older transmissions could be modified to have it. Depending on the adjustment of that lever, it also affects the shift pressure, so you get quicker shifts when the throttle is depressed more. I think most of us want quicker shifts all the time, but the general public wanted smooth imperceptible shifts at light throttle. These cars do stay in second when you're just tooling around town. They don't usually shift into third until you hit about 30 or 35. I'm not sure what the symptoms of out-of-adjustment bands are, but hopefully someone here can describe that.
 
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Thanks Bronze. I know its probably my fault the way I think. I want everything to work perfectly, even 50 yrs old cars. I'm one of the few that like the imperceptible shifts rather than a quick car. I guess if I wanted a fast car, I would have bought a new Telsa. All 1960, 1970 musclecars are considered slow today, but I just love the way old cars look, smell, feel and drive.
 

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1970 Chrysler service manual calls it “throttle pressure rod”. Look it up sometime. It tells the trans where your foot is on the gas pedal and it increases internal fluid pressures so it doesn’t toast the friction materials. Bit will still have soft shifts for grandma drivers.

manual valve bodies eliminate this linkage and fluid is max pressure at all times.

We car guys call it kickdown linkage. That’s what is it on a GM car, and thy have a vacuum modulator for throttle pressure sensing, amd the linkage kicks to passing gear. Not exactly how a 1970 TF operates.
 

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Hopefully someone will correct me if I'm wrong but I think that not only is that your kickdown linkage it also looks to be waaaay out of adjustment. Shouldn't the other end of the slot in that linkage rest on the pin?

If its out of adjustment that would explain your symptoms of a missing third gear and not downshifting.
 
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Thanks 413. Makes more sense to me now.

thehee - you made me remember that in 2005 I changed the Holley to a Thermoquad and I love it. Best carb I've ever had. I dialed it in 2005 and never touched it or had a problem with it since. I had to weld on a piece to the throttle pressure rod to lengthen it to work correctly which can't be seen from pic. I think I played around with this for a month before I thought I had it dialed in....but maybe not, maybe I never had it right. I'll look at it again. Thanks for everyone's help!
(Please remember, this car was abused, raped and trashed before I got it. It probably saw air and flew like Dukes of Hazzard too since oil pan, steering were bent. I fixed those and I removed tons of dirt from front, but it'll never be perfect.)
 

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1970 Chrysler service manual calls it “throttle pressure rod”. Look it up sometime. It tells the trans where your foot is on the gas pedal and it increases internal fluid pressures so it doesn’t toast the friction materials. Bit will still have soft shifts for grandma drivers.

manual valve bodies eliminate this linkage and fluid is max pressure at all times.

We car guys call it kickdown linkage. That’s what is it on a GM car, and thy have a vacuum modulator for throttle pressure sensing, amd the linkage kicks to passing gear. Not exactly how a 1970 TF operates.
I was beginning to think I was the only one that knew it wasn't a "kickdown" linkage.

Thank You!

To the OP, and I do this just to be sure... You are checking the fluid in neutral with the car running... Correct? Sorry, this comes up every once in a while when there are trans issues and I've mentioned it and 9 out 10, they are checking it correctly... But that one time that they aren't....
 

CBODY67

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In many cases, the min throttle upshifts into 3rd usually happen too early on TFs with factory calibrations. On our '72, it would go into 3rd at about 25mph, with a 2.7 rear axle ratio, which meant that after it shifted, any acceleration was "on the converter" (i.e., lazy) rather than "geared". So, after that and on our '66 Newport 383 with 2.76 rear axle ratio, I determined that the 2-3 upshift should happen at a road speed where the engine would be at 1000rpm after the shift. Rather than otherwise.

On the '66 Newport, with the threaded rod adjustment, adding two more turns of pre-load on the rod put it there. On the Newport with 2.76 and H78-14 tires, that was right at 28mph. This also raised the automatic part-throttle shift points a few mph higher, which worked well in "fast" city traffic. With the factory settings, I was getting left in the exhaust fumes of the other cars. First, I tried upshifting manually, which helped, but it would be better to have the trans do it itself instead, which lead to the tweak of the kickdown linkage. WOT upshift speeds were not affected.

By 1970, they had gone to the slotted road adjustment like on your car and my '70 Monaco 383 4bbl. So I played with the adjustment to get the 2-3 upshift at 25 mph, as the car had 3.23 gears and HR78-15 tires. Worked well, too. NO problems with either transmission. NO cooked fluid or other signs of distress, either. This was a very small deviation from the factory setting, too. Just my experiences.

There was a special procedure to do the base adjustment Seems like it involved springs to hold the trand-end rod fully forward as the carb rod was held on the carb linkage stud? More involved that it should be, I thought. By 1980, they'd hidden the adjustment under the car. Similar springs held things as the carb end was adjusted. BUT . . . I got the same result by using a thin black plastic wire tie to effectively providie more linkage preload to the factory adjustment. I put the wire tie at the rear of the carb rod slot, on the bottom. ONE is all it took. The car felt peppier and more happy, afterward.

The part-throttle kickdown 3-2 happened in 1971. BUT by that time, I had devised a scheme on the '66 Newport to do the same thing, manually. With a little practice, just as i was throttling into the car to get on the freeway, I would slip the shift lever into "2" manually with very little more throttle input. This was "geared" acceleration rather than "on the converter", as WOT was not needed and would have gotten the attention of passengers (including my parents). So, it all happened smoothly and quickly, just as it would on a car with part-throttle kickdown. "Practice makes perfect".

End result in all cases, MORE acceleration with LESS throttle input, which should equate to lower trans fluid temps (a little bit) as the torque converter was slipping less. AND no need for the carb to go into the power mixture mode, either.

Just my experiences,
CBODY67
 
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I measured the distance from the Holley before I took it off and mickey mouse welded the same distance for the Thermoquad. I remember I kept driving around and adjusting the rod bolt to the point where the rod wouldn't go back any further at WOT. So shouldn't I be experiencing early shifts (which never happens)? Only problem are late shifts from 2nd to 3rd and sometimes not downshifting at WOT. I'm guessing the throttle starts pushing back the rod around 1500 rpm. There are no adapter kits from Holley to Thermoquad linkage, are there?

Thanks for all the hlep. I thought I would only get a couple responses.

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You are getting late shifts because there is no spring pulling that linkage forward To the pin on the carb. Do that and it will shift earlier.

sounds good on the WOT adjustment.
 

CBODY67

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When the throttle opens, the linkage should move with it. NOT related to any particular engine rpm.
 
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Finding the right spring tension took time but I do notice an improvement. (Too heavy a spring and it was pulling the idle up by itself). I've only driven it once since but 2nd the 3rd seems happy now. WOT doesn't hesitate, but I've only driven it once so maybe it'll give me grief in the future.

Thanks for the help everyone....onto the next problem!
 
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