Shift kits.. do you really need one????

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Bakerlite

Bakerlite

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The more I look into a shift kit for a Torqueflite the more I question just what it does and more importantly why they do the mods they do.
I think it's time we really looked at what we are doing to these transmissions and why we are doing it.
Is a shift kit the right way to go? Or should we be actually making some internal mods to the trans to make it shift better?
There are two components, and one piece of information I can see as value in shift kit. Ie, the TF-2
1) The upgraded line pressure spring.
2) The new manual shift valve that charges the converter in Park.
Modifying the holes in the separator plate, if required.
The rest I'm not so sure about so lets discuss them.
First, the orifice restrictor for the 2-3 shift. If the idea is to free up and increase oil flow in the trans, then why would we want to do this? And will doing this shorten the life span of the clutch? Is there a better way??
 
I think I'll follow this I can't add much. All's I know is I have always added them. Was told when I was young that they would increase the life of your TF. I will say I have put some many miles on TF that had them in them. I do like the positive shift also.
 
If you are not going to hot rod the car, not needed. My 66 Dodge went 120,000 miles with no shift kit and had to rebuild because an O reng was pinched by the factory when assembled. If your a goimg to race 9i.e. street/strip thne put one in it. Trans Go kits are very good and don't require all the work you are proposing. If it's a 904 than I would put in a shift kit to keep from losing the second gear band which is the weak point of that trans. My opinion at 71.
 
I used to do transmissions for a living in another life :) and I can explain a little.
First, the cup plug is not for applying but for timing the release of the previous gear, so that you don't end up with a flare between gears.
I don't have a shift kit in mine because I can do what I wanted with internal mods.

I have the pressure raised and the separator plate drilled for quicker firmer shifts and a spring on my TP rod to delay the shift a little.
Under normal every day driving my car shifts into second at about 20-25 mph, and into 3rd at about 40-45
I don't need it to bark tires on the shifts, just a little quicker apply.
Doing it this way does not raise the wide open shift points, only the low and midrange shift.
If I also wanted it to shift later at WOT I could take some weight off the governor valve to do that.

The main job of a shift kit is to get into the next gear faster and with less slippage, and at a desired RPM.
Wanting quicker shifting is a no brainer, and less slippage of the clutches on the apply means less wear on clutch and band material and less heat buildup in the trans.
This can be taken too far though to the point of premature hard part failure of shaft splines, planetary gears and sun gear shell teeth. (overly hard shifts)
In my oppinion, the most imortant parts the shift kit has are the springs to make the shift valves operate at the right times, because when you raise the mainline pressure it affects the timing of everything else.
Kick down (passing gear), for example will change a lot from a relatively small change in mainline pressure and the shift kit spring compensates for that higher line pressure.

A person that knows what they are doing can do almost eveything a shiftkit can do with a drill, grinder and a few little springs, but most people are not capable of doing it.
 
TrailBeast said:
First, the cup plug is not for applying but for timing the release of the previous gear, so that you don't end up with a flare between gears.
Click to expand...

This ^^^^^ X1000. In the Torqueflite, the release of the bands is very important to speeding up and firming up shifts. That's one reason why I always recommend cast rigid bands instead of flex bands. It's not the apply time, but the release time that's important. Some kits don't speed up release time. This can result in shifting into the next gear while momentarily still engaged in the previous gear. This can actually give a "false firm" shift and make you THINK the transmission is shifting firmly, when in fact it is in two gears at the same time for an instant.

Shift kits are an important piece to the performance transmission puzzle. By raising line pressure and reprogramming the valve body that enables the clutches to have more holding pressure since the line pressure is increased. The kit also speeds up shifts so there is less flare up between shifts.

Go to Allpar.com and read Tom Hand's (VOETOM) article on the Torqueflite. He gives very descriptive information with fluid flow charts as to exactly what's going inside a Torqueflite. What they need in terms of performance usage and why. It's one of the best articles ever written on the Torqueflite far as I'm concerned.
 
Gil Younger (Mr Shift of TRansgo) developed the TF shift kit to address 1 design "flaw" and to firm up the shifts, therefore putting less time on the clutches, and also allowed you to defeat a few features like downshifting into first and holding gears. The perceived flaw was the convertor fill circuit (also the drainback his new spool valve retards) and his improvement was firmer shifts and higher line pressure. These may make your trans live longer (debatable, what about the pump?) and allow firmer shifts. Thats about it. I see it more of a crutch for an older trans. A new trans behind a factory 440/hemi did fine.
 
I'm not sure you guys have this all correct. Based on my experience doing them since the late 80s...

"the cup plug is not for applying but for timing the release of the previous gear, so that you don't end up with a flare between gears."
"Flare" is the rise in rpms that happens when the release of one holding mechanism and the apply of another. Normally when you increase line pressure there is less flare, and in the case of the 2/3 shift, it's overlap, not flare that's the problem. In the case of the cupped plug - it slows down the 3rd gear apply to give the 2nd gear band a chance to release. The cupped plug goes into the high gear apply passage.

"I have the pressure raised and the separator plate drilled for quicker firmer shifts and a spring on my TP rod to delay the shift a little."
The enlarging of the plate passages, the removal of the casting wall, the removal of the check balls, and the removal of the spring from the accumulator all decrease the time it takes for the trans to shift. The firmness comes from the combinations of line pressure, kickdown pressure, the changes in the shift circuits, and the forces opposing the holding mechanisms - those being the Belville spring in the forward clutch, the multiple springs in the high gear clutch, and the ratio of the kickdown (2nd gear) lever. It's not a couple things - it's all of it working together.

"In the Torqueflite, the release of the bands is very important to speeding up and firming up shifts."

I disagree. The rear band is not applied in stock valve bodies in Drive ("D"). It does get engaged in Break-a-way first ("1") but there's a very stiff spring to release it, and it's a smaller diameter (smaller surface area) so it pulls off very quickly as soon as the pressure is dumped. When it shifts up into second (in "D" or "2") the low/reserve band loses pressure and releases but not as fast as the kickdown band can apply. So it's common to have overlap (feels like a shudder) when going 1st to 2nd at part throttle (less rpm than a WOT upshift). When it goes from 2nd to 3rd the kickdown band servo loses pressure and the large spring works against the kickdown lever's ratio to releasee the band. While that's hapening the high gear clutch pack is getting pressure. That pressure acts against the return springs in the clutch pack. By installing that cupped plug the volume of fluid allowed to pressurize that clutch pack is reduced, and the affect is a slower 3rd gear apply. The biggest affects on 2nd gear release is not the band, but the spring and that lever ratio. That's why most good builders don't use the 5.0 lever. The best compromise is the 3.6 or 4.2 levers. If you get the return spring count, line pressure, and lever ratio right - the 2/3 shift feels instantaneous and precise. Doesn't matter what band is used really. The lighter double wrap is fine for most cars but does not have the holding capacity of the 1-piece. The 1-piece can hold anything but can slow down the apply. Trucks and heavy towing applications would normally use the 1-piece.


I'd like to here Fishy's opinion on these. Maybe I'm completely off...lol.
 
perfect timing for this thread, as im throwin a shift kit on this weekend or possibly friday. (bottom seal is leakin anyhow soooo)

i will post a reply n tell if i notice anything. right now 1-2 is really slow, and i bein all this new found power i cant wait for it to shift
 
Done right, a shift kit is going to benefit any trans, street, strip, whatever. They made them soft from the factory on purpose to feel smooth, which is what most customers wanted. I put the TF2 in my Chrysler a few year back and the difference was very noticeable - quick shifts with minimal overlap. The trans just feels tighter and more crisp. That car chirps 2nd at WOT, which is pretty impressive for a still mostly all stock 42+ years big, old land barge.
 
Buddy owns a trans shop. He does not use shift kits, a drill here and there, perhaps a bit of welding here & there to obtain firmer shifts. He has told me time & time again there is nothing to be gained by having the car shift as firmly as some folks seem to think it has to....only thing that happens is busted parts. Sure you will find some folks that say this is complete bs......to each there own....
 
340-4spd said:
Done right, a shift kit is going to benefit any trans, street, strip, whatever. They made them soft from the factory on purpose to feel smooth, which is what most customers wanted. I put the TF2 in my Chrysler a few year back and the difference was very noticeable - quick shifts with minimal overlap. The trans just feels tighter and more crisp. That car chirps 2nd at WOT, which is pretty impressive for a still mostly all stock 42+ years big, old land barge.
Click to expand...

The first line here is about as true as you will get......key words being the first two....problem is everyone seems to think that they will gain something by having there trans shifting extremely hard...
 
moper said:
I'm not sure you guys have this all correct. Based on my experience doing them since the late 80s...

"the cup plug is not for applying but for timing the release of the previous gear, so that you don't end up with a flare between gears."
"Flare" is the rise in rpms that happens when the release of one holding mechanism and the apply of another. Normally when you increase line pressure there is less flare, and in the case of the 2/3 shift, it's overlap, not flare that's the problem. In the case of the cupped plug - it slows down the 3rd gear apply to give the 2nd gear band a chance to release. The cupped plug goes into the high gear apply passage.

"I have the pressure raised and the separator plate drilled for quicker firmer shifts and a spring on my TP rod to delay the shift a little."
The enlarging of the plate passages, the removal of the casting wall, the removal of the check balls, and the removal of the spring from the accumulator all decrease the time it takes for the trans to shift. The firmness comes from the combinations of line pressure, kickdown pressure, the changes in the shift circuits, and the forces opposing the holding mechanisms - those being the Belville spring in the forward clutch, the multiple springs in the high gear clutch, and the ratio of the kickdown (2nd gear) lever. It's not a couple things - it's all of it working together.

"In the Torqueflite, the release of the bands is very important to speeding up and firming up shifts."

I disagree. The rear band is not applied in stock valve bodies in Drive ("D"). It does get engaged in Break-a-way first ("1") but there's a very stiff spring to release it, and it's a smaller diameter (smaller surface area) so it pulls off very quickly as soon as the pressure is dumped. When it shifts up into second (in "D" or "2") the low/reserve band loses pressure and releases but not as fast as the kickdown band can apply. So it's common to have overlap (feels like a shudder) when going 1st to 2nd at part throttle (less rpm than a WOT upshift). When it goes from 2nd to 3rd the kickdown band servo loses pressure and the large spring works against the kickdown lever's ratio to releasee the band. While that's hapening the high gear clutch pack is getting pressure. That pressure acts against the return springs in the clutch pack. By installing that cupped plug the volume of fluid allowed to pressurize that clutch pack is reduced, and the affect is a slower 3rd gear apply. The biggest affects on 2nd gear release is not the band, but the spring and that lever ratio. That's why most good builders don't use the 5.0 lever. The best compromise is the 3.6 or 4.2 levers. If you get the return spring count, line pressure, and lever ratio right - the 2/3 shift feels instantaneous and precise. Doesn't matter what band is used really. The lighter double wrap is fine for most cars but does not have the holding capacity of the 1-piece. The 1-piece can hold anything but can slow down the apply. Trucks and heavy towing applications would normally use the 1-piece.


I'd like to here Fishy's opinion on these. Maybe I'm completely off...lol.
Click to expand...

I think your spot on.. your exactly on the same page I am.. no one ever talks about increasing the servo release spring pressure.. There are different springs available, depending on the year and also what application your trans was destine for when it left the factory. Transgo add the cup because they know joe average won't fiddle with the internal hard parts. People tighten up the pack clearance and then delay it with the cup.
I think the cup is a compromise . In fact I'm going to go as far as saying I think adding this cup could shorten the life of the applied clutch, simply because of the nature of how a small restrictor in a larger passage works,but then I could be wrong about that.
I think we need to look at just what we are changing, why, and if we can put some of these "shift kit" parts aside and do a better job with a better selection of internal parts.
 
TrailBeast said:
I used to do transmissions for a living in another life :) and I can explain a little.
First, the cup plug is not for applying but for timing the release of the previous gear, so that you don't end up with a flare between gears.
Click to expand...

I thought this cup was used to stop 2-3 bind up, not 2-3 flare..
 
I got this from another forum.. this nis sort of what I'm talking about..

"The valve body, itself, has only limited control over the overlap period. When the valve body commands the 2-3 upshift, fluid is routed to the kickdown servo to release the band and fluid is simultaneously routed to apply the front clutch.

If the kickdown band is properly adjusted, a known quantity of fluid is needed to release the band but, because the clearance in the clutch can vary widely (and isn't adjustable externally), the quantity of fluid required to engage the clutch can also vary widely.

If the front clutch clearance is at its tightest allowable factory tolerance (.025"), a mere 7 CC's of fluid is required to engage the clutch while 27 CC's are needed to fully release the band. As one can see, with this much discrepancy in fluid quantity, the clutch will tend to apply before the band can release; big time overlap.

If the clutch clearance is at its maximum allowable factory
tolerance (.125"), 34 CC's of fluid are required to engage the clutch. This discrepancy in fluid quantity would tend to make the band release too soon before the clutch can engage and you have engine RPM flareup. (Since the trans is technically back in 1st gear)

Additional factors that can influence the overlap are the size of restrictor orifices in the fluid circuits that limit the velocity of fluid flow and the configuration of the return springs in the servo/clutch.

If one is assembling the transmission, the proper choice of clearances and spring combinations goes a long way to attaining the proper overlap, but if one is working with an assembled unit , already in service, adjustments are limited.

Attaining the perfect overlap period with all of the possible variables is akin to choreography; this is what the reprogramming kits attempt to do, to balance the action of the valve body and the existing hydro/mechanical components it controls."
 
There's a lot of talk about the TF-2 shift kit, nothing wrong with it, if that's the type of shift you want. I've got the little kit in my 74 Challenger, the SK-TF. It was put in by a talented transmission builder, and it does exactly what it was intended for, reducing the overlap time between shifts. Under normal throttle, the shift is quicker, but not harsh, however, under full throttle it'll bark the tires.
The TF-2 was intended for heavy duty useage, such as in trailer towing, 4x4 situations, and those that wanted that kind of shift in their car. Originally Transgo had 4 shift kits for the TF. There was the SK-TF, also known as the builders kit, the TF-1, the TF-2, and of course the TF-3 for those that wanted a full manual valve body.
IMHO, if you're not beating on the car, but want to improve the shift quality in your TF, just install the SK-TF kit. It'll cut down on the overlap, but won't give you a hard shift unless you're under WOT.
Installing or not installing a shift kit is usually the builders option, based on the information received from the car owner, and what the vehicle is being used for. In the almost 30 years I worked in the industry, there were builders that installed kit in every transmission the built, and others who didn't unless the customer wanted one. In this era though, it seems like every transmission has issues, and shift kits are available for all transmissions to help cure these problems.
As it was mentioned before, factory transmissions usually had a nice soft shift. God forbid you should feel the transmission change gears, and while this may have made the owner feel good, those long overlaps and soft shifts weren't doing the friction plates in the transmission any good. By the way, a shift kit won't really help a transmission whose life cycle is just about finished. They don't make a bad transmission good, but will make a good transmission better.
 
I'm go and make this one short as these are the facts to why you want one.

TrAnsmissions love to shift harder and quicker. Not abusively hard. They like it better, live longer since there less time the internals are creating less friction and heat which they don't like for long life. It also quickens the car in acceleration. All for cheap!

Add a cooler and a deep pan and it'll live a Long happy life shifting quicker and cooler.
This is why you want one.
 
rumblefish360 said:
I'm go and make this one short as these are the facts to why you want one.

TrAnsmissions love to shift harder and quicker. Not abusively hard. They like it better, live longer since there less time the internals are creating less friction and heat which they don't like for long life. It also quickens the car in acceleration. All for cheap!

Add a cooler and a deep pan and it'll live a Long happy life shifting quicker and cooler.
This is why you want one.
Click to expand...

I think I may not have made the reason for this thread clear. It's not about if you should have a shift kit, it's more about if you really need to use all the parts and do all the mods that the kit asks you do to, when you are building a trans from scratch.
The first part I'm looking at is the cup plug and it looks like if you were to use the correct selection of parts and clearances at build time then this plug would not be necessary..
It's easy to say.. " oh yeah, just stick a shift kit in it" but how many people really know exactly why they are doing these things.

As I said, so far, there are two parts I would use in the kit. That's the
New manual valve and the stiffer line pressure spring.
I'd like to discuss the rest of the parts and why we would use them..
I think it's a good topic and would give a different perspective on trans building..
 
low speed roller has a tendency to leave the case. use a shift kit and all is well.
 
How does it help rays266?? I also assume your talking about the sprag?
If it's the sprag, then they seem to want to leave the case due to driver abuse more than oiling issues..
Also just to add, you can drill the case to supply more oil to the sprag.
 
Hmmmm....I think rays266 may have just depleted his Torqueflite knowledge in just one line of one post.
 
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