Shift Kit 2-3 overlap cure?

[PLUM_72]

How do shift kits prevent the 2-3 overlap?

[fox]

Actually the shift kit only REDUCES the overlap to a point where you don't feel it. It is done by increasing the fluid flow to and from certain parts of the trans.
Most people don't know it but the front band should be adjusted by loosening it until you get a slight flair-up shifting into 3rd then tighten it about a 1/2 turn. I bet these comments cause some opinions to surface!

[cuda66273]

Hey Fox you seem to know your stuff,
have a look at this article and tell me what your opinion is..as with most stuff there's a thousand opinions on everything here some right and some wrong...I just try and sort it out....

http://www.4secondsflat.com/Bandadjustment.html

It was actually written by a person I feel is an expert in the field.

[fox]

I have seen it before, but never tried it. The first thing I am concerned about is that each of us have different strength in our hands. Then is the issue of used bands and also is this done hot or cold?
Actually the idea of putting the rear wheels up on stands and bringing the rpm up to 3,000 in manual low, shift to 2nd while having someone watch the wheels to see if they slow or stop. then continue to 3rd and see if the wheel action is the same.
There will not be a bind -up in the 1-2 shift but will be in the 2-3 shift if things are not set right.
2-3 bind-up can actually cause the wheel to completely stop if it is severe!
Most people think a tight front band will shift firmer but it causes more bind-up.
BTW, I'm just average in skill, there are some real sharp people here that could chop me up like the old BASS-O- MATIC on Sat. night live!
I enjoy this site, my wife thinks I am here too much. I shoo her away.

[92whitedak]

I slightly preterbed, while at the same time excited, that there is finally another fox on this board Tell your wife you are getting payed to do it and you are saving up to buy her something nice and shiny. That should keep her at bay. Then, when the time comes, whip out a piece of chromed trim molding reading "hemi 'cuda" snicker snicker. You'll be hurting for days and I doubt you'd have a chance of her making it feel better. Anyway, Plum, if you'll notice with the shift kit, it is basically just a flat plate with numerous holes and grooves cut in it. As Fox (ooo, thats odd) previously stated, the shift kits improves fluid transport to the shifting pistons of your tranmission. Overlap is near impossible to eliminate but what fox again said is correct. It simply lowers the feeling of it. I'm not sure why they don't produce newer vehicles with standard shift improver kits. I'd PROBABLY buy a vehicle with a "smoother shift" for an extra 300-400 bucks rather than the 78 bucks for the aftermarket shift improver kit. And to say the least, they are incredibly easy to install. I feel sort of weird echoing fox but everything he said was correct. Number 1 being that a tighter band does not, as many would conviece, create a smoother shift. There needs to be a slight "slip" if you will in order for a nice tranfer to take place. Number 2 being that he was right about loosening the band until almost no grip is achieved (a "flair up" in the shift") and then tightening it down a half a turn, or as I like to commonly use, about 200 degrees (a little more than half a turn). I got a good laugh about the BASS-O-MATIC. Good to see the two foxes have a sense of humor. When are the rest of you guys going to catch up? By the way, don, now you'll DEFINATELY have to call me "Deac" when this guy and I are both subscribed....

-Fox Deacon

[fox]

Most chryslet trans can be greatly improved (both durability and shift feel) with out drilling holes. Just get the clutch clearances reduced to the minimum spec and the shaft end play correct.
Thus you don't need to drill holes and make things hard to correct.
By reducing the clutch clearance, the piston in this clutch moves less so it needs less oil to reach apply.
Also the line pressure needs to be raised. Now you are going to ask me 'how much'. Best answer is to put a gauge on it, record it and then drop the pan turn the correct screw three or four turns. Put the pan back on and and record the new reading. It should be up by 10# . There really is more to this so don't get the wrenches out yet. This adjustment will change the shift points. The kick-down cable (or rod )should be checked before for proper adjustment and adjusted after to put the shift where you want it.

[Slant Cecil]

Question about the jack stand test. If tested with a stock type(non-manual) valve body, can the 1-2 shift be made manually? It seems the tire speed would slow because of the rear band dragging, if too tight, when coming out of manual low. Should the 1-2 shift test be done with the shift being made by the valve body?

Cecil

[John Kunkel]

The foursecondsflat band adjustment method is the biggest load of crap on the web. The author assumes that the tightest possible band clearance is preferable and his claim that it is "easier" and "more accurate" are outright bull.

I put it right up there with the oil filter "study".

[cuda66273]

Now John don't go hollering like that...tell me why..i used it on my tranny and it works just fine and has for over 300 passes...tell me a different way I'm all ears.
I asked for an opinion not a slap in the head...

I'm all ears..

Don

[23T]

Thank you Ma Mopar for making 4 sp manual trannys

[John Kunkel]

cuda66273,
If you're happy with the procedure, stay with it. Have you used the recommended procedure and then gone back to see how many turns out the adjustment turns out to be?

I see no logic in this adjustment method, as stated earlier the are way too many variables such as:

Personal strength.
Parasitic drag elsewhere in the drivetrain.
The difference in parasitic drag in the trans due to tight/loose clutch packs and thrust washers.
The difference in servo travel with different ratio apply levers.
(the last item is a biggie)

Using this method is, to me, the exact same thing as going from Los Angeles to New York by way of Mexico City.

[b-1ken]

John: I like your stuff on TF's. I don't run them anymore (only have 'Glides now), but you present very convincing arguments. I'd be interested in your non emotional (please) take on the oil filter study. I wondered, myself, what credentials did the author have, if any, to make his evaluations.
Ken B.
By the way, do you have much experience with Powerglides (I love 'em).

[cuda66273]

I see what your talking about, I'll compare it to the factory spec next time we pull the tranny, but as it's a TF Mopar Tranny in a Mopar it could be many years before I ever have to remove it.

I'll be talking to the tech Guy's at TCI today on a 904 project and also Frank Lupo at Dynamic...I'll ask them what they think and let you know.

Thanks for the input

I know your a great tranny man, would you be interested in writting a rebuttle and alternate meothod for that page?

[cuda66273]

Mexico is nice this time of the year

[John Kunkel]

The kickdown band is a wear item, just like brake shoes. In a competition environment I would like to see the kickdown band adjustment checked on a regular basis, this way one can keep track of the wear rate. The only way to do this is to use the traditional turns out method.

As far as rebuttle (I've already voiced that) and an "alternate" method of adjustment, I consider the "twist the driveshaft" to be the alternate method and the traditional "turns out" to be the accepted standard. Some folks advocate using a sort of feeler gauge between the band lever and the servo plunger to check the actual free play but this requires removal of the pan for a simple band adjustment. This defeats the advantage of the external adjuster and winds up at the same place.

IOW, if it ain't broke, don't fix it. I view the "twist the driveshaft" method of band adjustment a solution for a nonexistent problem.

[PLUM_72]

Okay thanks for all the responces...so the consensus is that the shift kit will not correct 2-3 overlap? Whats with all the springs for the front and rear servos, kickdown levers, etc. Fox had mentioned to correct 2-3 issues keep a tight clutch pack. Is that all? Im in the midst of a trans project, and was wondering if a shift kit is necessary? I'm going with the 3.8 lever and 12 springs in a 4 disc front clutch. There is always the basic magazine article that shows the drilling of the seperator plate and adjusting the line pressure. The only other thing I was going to do is get a Sonnex manual valve for the convertor charge in park. The car is not a racer, its a cruise nite street car.

[fox]

Your on the right track. Just get the clutch clearance to .040 to .060 , the kit will reduce the overlap. If you want hard/quick shifts drill the holes and do the servo's.
I am not a fan of drilling holes in the valve body anymore. There are better solutions. The manual valve and the pressure reg. valve are both good idea's......

[John Kunkel]

I don't believe there is a "consensus" that a good reprogramming kit won't correct 2-3 overlap, that's their purpose. Not all "shift kits" are true reprogramming kits.

The orifices (orifi?) in the separator plate restrict the velocity of the fluid, if they aren't enlarged, all the other modifications will be in vain. The key to an efficient 2-3 upshift is timing, this can't be accomplished with certain clutch clearances alone, there are too many variables. A tight clutch pack will often eliminate engine rpm flareup during the 2-3 upshift but it might actually increase overlap which is often perceived as a firm shift by the butt meter.

The goal of the reprogramming kits is to choreograph the shifts by controlling the volume qnd velocity of the fluid flow to the various components involved in the shift process. They do it pretty well.

Be advised, shift kits aren't a band-aid for an ailing transmission, the instruction sheets state this. If the trans isn't in good shape to start with, no amount of tweaking will help.

[cuda66273]

Thanks John that's good info...can I copy your post over to my web site?

Transmissions are a fairly complicated beast, if a guy wants to overhaul his own would you have any recommendations on a good manual to buy and once all the new parts are assembled and it's ready to go back together do you have a favorite shift kit that you like to use and is there any "Hot Tips" that you could touch on here that would get us Shadetree guy's going in the right direction?

[92whitedak]

I like how Don still refers to himself as a "Shadetree guy". Tell that to the dude WITHOUT a garage and a bridgeport mill (cough cough me). As someone who really only understands the internal dynamics of a transmission and now really what goes into making them better/worse, I'd be very interested in reading something on it. Thanks

-Deacon

[John Kunkel]

For overhaul info, the factory service manual is hard to beat and that, combined with the instructions in kits like the B&M Transpack, TransGo TF-2 or the Superior #10430 should produce a good shifting trans.

For an all-in-one kit, the B&M Transkit isn't bad. It has good quality friction materials, the Transpack shift kit and includes instructions for other modifications. TCI makes a similar kit but it lacks instructions.

There are a lot of other "shift kits" out there, many are "problem solvers" that are specific to certain problems. I would avoid any kits labled "shift improver", they don't cover the entire spectrum of operation. Kits such as those I mentioned above are reprogramming kits and they address the major needs in a performance transmission.

Anyone is free to use any of my rantings.

[skankweirdall]

I have to agree with John. I did trannies at a dealership for over 18 years, the T/F's are the simplest strongest 3 speed tranny out there. They ain't hard to do. I also would not tighten up clutch clearances. As John stated it can increase the overlap period and also cause parisitic drag and premature wear. Let there be room for the fluid. Since I'm basically a racer and not a street guy (drive a T&C minivan) I'm all for the T/A manual valve body or any of the better trans brake valve bodies out there.

By the way my band adjustment procedure is 72 inch/pounds and back off 2 1/2 turns. If you have the pan off you can pry down on the lever and see that this gives you approx. 1/4" to 3/8". I never really measured it.

[cuda66273]

Thank you John and Skank your rantings are excellent...and very informative..could one of you guy's drop by and give the Fish Fry tranny a quick once over before the season starts.....I'll let you make a pass

John I took you up on your offer

http://www.4secondsflat.com/Bandadjustment.html

[skankweirdall]

I've always wanted to visit the NW Pacific area. Hmmm.

[FASTDARTCHESTER]

Question for trans gurus:

The kickdown band in the 904 I am rebuilding was so worn when I pulled it apart that it scored the hell out of the front clutch drum. So, I turned the drum down to remove the scores, then I gave it a finish (with fine emery cloth) like stock. The cast iron band was worn to the metal, but there is still plenty of meat on it.

Problem is: I wound up taking almost 0.075" off the diameter. I talked to a guy at Specialty Brake and Clutch and he said they can reline it with Kevlar up to 0.074" thick. This will put me almost to stock specs, only my drum is smaller and I have more friction material to make the difference.

The Question: Will doubling the thickness of friction material cause any issues with performance/shift quality?

Any input???

TD

[John Kunkel]

I've never had any luck refacing a badly scored drum. The process of scoring usually leaves hot spots where the cast steel becomes hardened and resists refinishing. The spot hardening can also be a source of stress risers which weaken the drum and could lead to disintegration. New drums aren't that expensive.

A word on band adjustments, when using the turns out method of adjusting, the actual number of turns to back out the adjuster depends on the band apply lever ratio. The levers come in several ratios, 2.9, 3.2, 3.8, 4.2 and 5.0. The different lever ratios will effect the travel of the servo.

To achieve desireable shift timing, the volume of fluid required to apply/release the servo should be consistent, so a different number of adjustment turns is appropriate for each lever ratio. Generally, the higher the lever number, the tighter the adjustment should be. For example, the common 3.8 lever would take 2 turns out while the 5.0 would only take 1 1/2 turns out.
For other levers:
2.9= 2 1/2 turns
3.2= 2 1/4 turns
4.2= 1 3/4 turns

Basing the turns out on the lever ratio will keep the servo travel and the volume of fluid flow consistent. The actual number of turns out can be juggled to change the 2-3 shift timing if desired.

[FASTDARTCHESTER]

Can you be specific on "never had any luck"? Did you have drums that actually failed on you? Do they tend to wear a re-lined band quicker?

Thanks

[skankweirdall]

I personally would not turn a front drum. Those are spinning pretty fast in first gear even if the overrunning clutch is holding. Should it roll over that drum triples or quadruples in RPM. Either way it spins at an alarming RPM and that is the part that shatters and speads carnage and shrapnel everywhere. I say it's best not to mess with it.

[cuda66273]

More good stuff already loaded on the web site..THANKS!

Skank....Should I pull the tranny while it's still up on the jack stands?

[skankweirdall]

cuda, wish I could get up there. It's not going to happen anytime soon though.