transmission slipping, please give advise!

You are absolutely right on that, clearance is the main culprit in most cases. The band is released on the 2-3 shift, and if the clearance is not in spec's, it will take longer to engage clutches etc. Leaky piston seals along with servo, can also be involved. The larger C and H servo's, allow the band to come off faster as well as apply it with a bit more aggression when needed. Most shops will set these clearances mentioned before, to factory spec's which are great for normal street driving. But give the little darlin's some aggresive hot rodding, on the throttle, and they just are not going to work quite the same. Takes a bit of doing to get the right thrust washers and clutch pack clearance a little tighter for a good shift in all gears. Adding an extra disc in the drums is well worth the effort, in performance. Most shops are not in that type of business though, and for daily drivers, their stock rebuilds should work if they do them right.

 

The band adjustment is 10 foot pounds. If you use 10 inch pounds you are not getting the preload on the bands. tighten the band adjusting screw to 10 FOOT pounds and back the rear band out 3 turns and the front band gets backed out 1 1/2 turns. the "flare" that you get on the 2 - 3 shift is the band letting go before the hi clutch is taking hold. Adjusting the band will usually take care of the problem. If the high clutches were toast it would affect reverse too. As long as you have a solid reverse those high clutches are ok.

 

did anyone else see the date on this thread?...2003/ o5 /23

...:Handshake ...

 

Yes, but as some of us new folks get aquited with our cars, the problems that many of you have long sence resolved will be new to us

I would be willing to bet that this type topic will never go away. I for one am in the process of being de-flowered in the relm of tranny rebuild, and was just cruising any and all discussions I can find that might help me better understand what I'm doing.

I don't know if anyone cares, but I am photoing the process, mostly so I can remember where evrything goes

Lou

 

Welcome aboard. My boss has a cabin in your neck of the woods somewhere. Check out the sticky thread in the tech section about hot rodding your c4 and get her rippin'.

 

I wonder if this guy got his problem fixed, and what it was?

Lou

 

Just read this after worrying about my C4.. has the same 2nd to 3rd "flare" everyone is talking about. my reverse is rock solid as is the transition from N to D (1st to 2nd) is solid shift its early but tight. so if I adjust my intermediate band as per PaulS 10'lb then back out 1.5 turns this should cure the problem.. sure beats the hell out of a full rebuild as previously discussed.

 

The 2-3 flare is most often caused by:
a) worn clutches in the high reverse pack (too much clearance)
b) an error in the porting of some after-market valve body kits or valve bodies
c) a combination of the two

The how it happens is relatively simple; Second gear servo releases before the high clutch engages cause the engine to rev as the transmission shifts from 2nd to high.
My flare eliminator kit adjusts in order to make up for the wear that happens during a season of hard racing - it can also make up for some of the wear that happens in a daily driver but there is a point at which you simply must rebuild the transmission.

Sometimes a "shuttle-shift" is wrongly called a flare. The "shuttle-shift" is a shift to 3rd, back to second and then to 3rd again. This is caused by too little vacuum at the modulator. The vacuum must be at least 10" HG at idle in gear measured at the vacuum modulator. If you have a big cam, poor compression or a combination of both then the only way to fix the problem is to use a manual valve body - one that does away with the vacuum modulator.

 

mine the reverse is solid, its just the 2nd to 3r forward shift that is crap if I am on the gas. also dumps the shifts real early even under hard throttle. I will try the band adjustment and the modulator for the simple fact that is cheap and cant hurt. if all else fails when the cash flow is available I will just get another pre built transmission.

 

If you are going with a pre-built and you don't want any problems get one from Broader performance. Jay is a great guy to work with and has a history of building great products at a price that is low for the value.

 

Will a bad modulator cause white exhaust. I know several things that will, is this one? I gat the "flare Up" on my '64' Comet.

 

Yes, burning ATF will cause white smoke. You can check it by simply pulling the hose from the modulator - if there is oil in the hose the modulator is leaking.

When you say you have the "flare up" on your 64 are you talking about the 2-3 flare? Is the transmission fairly new or very old?

 

Yes. 2-3 flare. Transmission is original and not rebuilt. I changed the modulator and it shifted a little better but still flares. Which way do you turn the adjustment screw to tighten the shift?

 

if the filter was changed recentlly make sure the high preasure valve and spring didnt fall out, it it is held in by filter and will fall out into old fluild container, will cause slipping between gears and burn up clutches eventually, valve is about the size of a small nail,