727 2-3 shift flare up at wot

[Nachtfalke]

Freshly rebuild a-727 transmission from a transmission shop + they installed a transgo TF1 reprogramming kit for whatever reason.
Shifts fine at low to moderate throttle. At full throttle however, the 2-3 shift happens "too slow". Feels like as if it goes into neutral for a split second resulting the engine to rev up +500rpm. I'm concerned that it might destroy itself over time by doing this.

The trans-guy keeps telling me that the throttle linkage is adjusted wrong. Throttle linkage is adjusted with the lever all the way back at fullthrottle and i already tried each and every possible adjustment with no results. Kickdown works fine. I also checked the PRND-selector lever on the transmission to make sure it's not inbetween N-D or D-2.

It didn't do this before the rebuild and my previous car with 727 transmission never did this even with the throttle linkage misadjusted... so i can't really believe what the guy keeps telling me, however im no expert and the other car didn't have this reprogramming kit installed.

From a bit of online search i have found this:
http://www.binderplanet.com/forums/index.php?threads/transgo-tf-2-installation-tip.105752/
seems to be the same problem but with a TF2-kit (im guessing they are similar)

Not sure what to do now since im scared of opening up the thing and doing anything else than a oil-filter change, but i also don't want to pull the transmission out another 4-5 times in the hopes of finally finding someone who can fix this thing while spending 1000€ everytime they are taking a look.

Maybe just leave it like that and pray it doesn't blow itself up?

 

[vance.dykes]

it sounds like there could be a pressure problem. you would need to use a pressure gage on the pressure port on the side of the trans a service manual would tell you witch port and the p.s.i range. there is a air pressure test but you would have to remove the valve body to do this . this is in the service manual also it is not hard but being clean is the most important dont want sand and or dirt getting in this oil system. if the air test passed then you could up the line pressure but it would be best to redo the valve body and go with the stage 2 kit . you might find that the re builder put the wrong spring or did not do the auj,

 

[justcruisin]

If it was fine before the rebuild it may be due to the shift kit. Flaring on the 2-3 shift is normally a timing problem between the 2nd gear band releasing to early and or the high gear clutch pack engaging to late. There are a few things that change this, the transgo kit do a pretty good job of controlling shifts, (I have only fitted the TF2) normally with a shift kit a restriction is placed in the feed hole for high gear, this slows the apply of the clutch and allows the 2nd gear band to release without having both 2nd and 3rd gear at the same time, if the restriction is too small for the number of springs in the clutch the clutch will apply too late - causing engine flare up. The feed hole can be accessed with just dropping the valve body, no need to remove the trans. Removing the restrictor or increasing the hole size is not too hard, I would try that first. It is a good idea to tap a thread in the case so that rather than using a fixed size restrictor, an 1/8" NPT bung with a hole in it can be screwed in, simply change the bung out for one with a different size hole to achieve your desired timing.

 

[2quick]

You could try tightening up the 2-3 shift band about a 1/2 turn. It's on the outside of the case by the shift linkage. You'll know if you went to far, if it starts to bang when shifting.

 

[wyrmrider]

just call dave at transgo phone number on the transgo instructions or use internet they are in el monte ca

 

[YY1]

is the kickdown linkage installed and adjusted properly?

 

[Dipstick]

Removing the restrictor or increasing the hole size is not too hard, I would try that first.

Best advice.

 

[dvw]

The Trans-Go help line is good. Call them 1st. It may need the restrictor opened a bit, but ask the experts.
Doug

 

[Garys1969RR]

When it shifts from 2 to 3, the front band releases, and the high clutch applies. To get a good, fast shift, there is a split second where they are both partially applied. Sounds like the band is releasing too soon, causing it to run away before the high clutch applies. By tightening the band a half turn, as post #4 said, it keeps it applied longer, so it is releasing as the high clutch applies. This is the easiest way to try and fix it. If that doesn't work, then it may have another problem. Try that adj first. If you get it too tight, it will bang during the shift, as the driveshaft actually stops turning for a split second. Then you would need to back it off 1/4 turn. The initial adj is tighten adj bolt to 72 inch pounds, then back it off 2 to 2 1/2 turns. Just experiment a little. Be sure to tighten the locknut that's on the adj bolt.

 

[Challenger340]

When it shifts from 2 to 3, the front band releases, and the high clutch applies. To get a good, fast shift, there is a split second where they are both partially applied. Sounds like the band is releasing too soon, causing it to run away before the high clutch applies. By tightening the band a half turn, as post #4 said, it keeps it applied longer, so it is releasing as the high clutch applies. This is the easiest way to try and fix it. If that doesn't work, then it may have another problem. Try that adj first. If you get it too tight, it will bang during the shift, as the driveshaft actually stops turning for a split second. Then you would need to back it off 1/4 turn. The initial adj is tighten adj bolt to 72 inch pounds, then back it off 2 to 2 1/2 turns. Just experiment a little. Be sure to tighten the locknut that's on the adj bolt.

BINGO !
Tighten the 2nd band.

 

[Dipstick]

Tightening the band without first determining where it's set is bad advice. IOW, if it's already pretty tight and the flareup problem lies elsewhere, you're causing added drag.

 

[justcruisin]

I agree, the band should be set to work with your KD lever, however, you may well fix or improve the shift but you may over tighten the band and as Dipstick said, having the band not fully released will cause drag on the front drum. Best to go with the factory setting IMO.

 

[Garys1969RR]

Yes, adjust it to the factory setting first. See how many turns clockwise it takes before it stops turning. If it isn't about 2 1/2 turns, then it was set wrong.

 

[wyrmrider]

ask dave how he adjusts bands they have changed over the years
Gary's hint "when it stops turning" is a key
also lever ratio may make a diffference on that band

 

[dvw]

The band will not release to soon. It can take time to complete the 1/2 if its loose. But it's got to be really loose to cause a 1/2 flare. 2/3 flare? Never seen a band adjustment cause that. But the clutch can come on to late. That will definitely cause a 2/3 flare.
Doug

 

[Garys1969RR]

I have been able to change the 2 3 shift characteristics by changing the number of turns out on the kickdown band. So experiment a little. It's Pretty hard to hurt that transmission.

 

[Nachtfalke]

late update: been driving like this in sunny-weather-daily-use for almost 3 years now. I didn't want to void my warranty by touching any adjustments on the transmission since my transmission-mechanic put a blob of paint on the adjustment screw. Now that my warranty has expired i checked the kickdown band adjustment and it was almost exactly 2 1/2 turns out.

Factory service manual says "tighten to 72 inch-pounds and back off 2 turns // 1 1/2 turns for 426 cu."

I tried both settings and even tightened it to the point it banged on 2-3 shift, however it didn't fix my problem.

Now i would like to remove the restrictor, however im unsure where it is located or whats going to happen when i drop the valve body. Are there any springs or check-balls that i have to look for when dropping the valve-body?

Is the "Orifice Plug" the restrictor that i have to remove?

By the way i made a video showing the issue:

 

[justcruisin]

Do yourself a major favor and get Carl Munroe's book on 727"s and the factory service manual. And yes that is the plug installed from the shift kit in the high gear feed hole. IMO it is best to tap that hole for 1/8 NPT and use a bung with a hole in it.

 

[dvw]

Yes the picture shows the restrictor in the high clutch feed orifice. The valve body must be removed to access it. A sheet metal screw in the hole will allow it to be pulled out. However there may be an issue with the high/rev clutch. Worn frictions or a torn piston seal. If I was a betting guy Id say the outer piston seal in the high/rev clutch is damaged.
Doug

 

[4406bbl]

For what it is worth I have almost always had to pull that plug to stop the 2-3 flare up, even with tight front clutch clearance. Pull it and put your band back at 2 turns. Think about it, the band releases about the same no matter where it is set.