explain why one needs a manual shift

[AmadeusCharger500]

Can somoeone tell me why I need a manual shift valve body in my car which has a slap shifter. Is the stock valve body not okay for manual shifting? If so why does the car come with a slap shifter?

thanks

[John_Kunkel]

An automatic valve body will never shift as fast as a full manual because the fluid routing in the automatic is circuitous while the manual routes the fluid direct. The manual VB also has the advantage of being fully controllable; it will take off in any gear.

The slapstick shifter is intended to prevent missed shifts that can occur if the driver gets a little over zealous. Whether or not you "need" a manual VB depends a lot on the intended use. For a mostly street driven car a fully automatic VB with a good reprogramming kit will work better with the stock slapstick shifter. If a lot of manual shifting is done with the automatic VB the rear servo mods provided in the reprogramming kits improve shifting efficiency.

[AmadeusCharger500]

So all in all a new valve body is a good idea over the stock unit?

I am thinking about one the has the option of manual shift but will shift in automatic mode also.

[John_Kunkel]

I don't see any difference between a packaged reworked stock valve body (there are no "new" valve bodies) and one modified by a good reprogramming kit.

[Ghoste]

I think he means more or less the change between a "new to his car" valve body and the one that's in there now.  John is right though, your money is likely best spent on something like a good reprogramming kit.  A true manual valve body is a nuisance on the street for most people.

Out of curiousity John, are the "new" valve bodies such as the "Cheetah" just reprogrammed used ones or do they recast the aluminum in the fashion they want?

[Just 6T9 CHGR]

My Cheetah RMVB had a 1976 cast date on it so I think they are reconditioned ones

[John_Kunkel]

Some of the more complex manual VB's have CNC machined transfer plates and separator plates but the main valve body is still an old reworked original piece.

[SpudRacer]

I've always been a "manual guy" myself.   I've got a 440 and a stock 727 with the stock valve body.   Every time I drive the car, I find myself shifting to 2nd, then low when coming to a stop, and then shift back up as I go.   I rarely-to-never just leave it in drive.   I also drive this way with the wife's Volvo XC70 which is none-the-worse-for-wear over the past year.   I hope this isn't hurting my trans.... is it??

Would I be better off installing a manual valve body?   The only thing that's kept be from doing it so far is it takes the car farther from stock, and if I ever have a brain fart and let an idiot drive my car, he/she may blow my engine by not shifting out of first, or will wear out my clutch bands by starting from every stop in 3rd gear.   (Nobody has driven the car save my wife since I got it).

It hasn't seen any drag race time yet, because I live in the sticks, and it would be a 3-4 hour drive just to get to a track, but I may make the trip if a track opens up closer (keeping my fingers crossed).

Suggestions???

Tom

[Ghoste]

You aren't hurting anything.  But you might enjoy a manual valve body if you are doing that way all the time anyhow.  It will shift harder and a little quicker.  If you get a 1st band apply one, then you can eliminate the worry of hurting the sprag.  You also won't need to worry about kickdown adjustments.

[SpudRacer]

If I get a first band??  What does that mean?  As for the kickdown adjustments, do you have a hidden camera under my hood?!?!?!  I've adjusted it twice in the last week trying to get it where I like it.  It's not there yet, but much closer.

Tom

[Ghoste]

It's a race thing.  Unless you're pounding the car, you won't need it but I felt obliged to mention it since you're considering what is for the most part a race valve body anyway.
It holds the low band on so if the sprag fails, the drum isn't spinning.

[SpudRacer]

Learn something new every day!!

THanx Ghost

Tom

[John_Kunkel]

Rear band apply and sprag failure aren't a race thing, misuse/abuse on the street is just as likely to result in a sprag failure; it's about power input and traction.

Continuous manually shifting of an unmodified automatic does cause accelerated wear. 

[Ghoste]

I agree on the sprag issue John in principle but wouldn't you agree the most common time for it to occur is coming from a burnout in water onto dry pavement?  A given that most all race trans are fortified in this area but I'm thinking about the occasional weekend warrior who drives to the track and maybe has a set of slicks or even just drag radials and runs the otherwise stock tranny?
On the accelerated wear, do you mean from the actual function of manually shifting or that it would be shifted more often?

[John_Kunkel]

Because street cars usually see more miles than a race car, misuse on the street is just as likely to cause sprag failure. Lots of drivers unknowingly strain the sprag by their driving habits.

When a TF is continuously manual shifted from 1-2 there is accelerated wear on the rear band because it relies solely on spring pressure to release it; the slow release results in drag induced wear. The rear band isn't applied in Drive, only in manual 1st.

Reprogramming kits address this issue and supply components that shorten the release time and reduce drag/wear but there will always be more wear when manually shifting.

[SpudRacer]

Then answer me this...  if I continue to shift manually, and eventually wear out the bands, are these parts included in the "reprogramming kit"?

Is reprogramming something I can install myself?  Is it basically replacing the valve body.  Like many others, I have this fear that once I pull down the valve body, balls and springs are going to fly out everywhere, and I'll have no idea what went where.

Tom

[Ghoste]

It depends on the kit.  Some kits are little more than a replacement separator plate and drilling instructions and some are rebuild kits.  A reprogramming and rebuild kit is what you need for a worn out one.  If you just want to do the valve body, it's a good place to start and become used to working on auto tranny's.  Springs and balls won't go flying everywhere although there are some balls inside.  Just take your time and follow the directions.  Get a quality kit and the instructions will be clear.  You can also purchase complete valve bodies such as the Cheetah and simply swap them.
A complete rebuild is not difficult although there are a few specialized tools. 
Above all, keep everything operating room clean.

[SpudRacer]

thanx Doc

[Ghoste]

Don't want any Junior Mints flying in there. 

[John_Kunkel]

Then answer me this...   if I continue to shift manually, and eventually wear out the bands, are these parts included in the "reprogramming kit"?

Is reprogramming something I can install myself?   Is it basically replacing the valve body.   Like many others, I have this fear that once I pull down the valve body, balls and springs are going to fly out everywhere, and I'll have no idea what went where.

Reprogramming kits are simply a sophisticated "shift kit" and can be installed by any ordinary gearhead. The B&M Transpack, TransGo TF-2, TCI Trans-scat, etc. are aexamples of reprogramming kits. This page has the instructions for the TCI kit, the other brands are similar:
http://www.tciauto.com/instructions/220000_inst.htm

There are a couple of overhaul kits on the market that include a reprogramming kit with the overhaul parts but none supply a rear band which is the part that is subjected to excessive wear when manually shifting.

[Just 6T9 CHGR]

I thought using a manual VB is better for the clutches because there is no slippage.....
Starting off in 2nd or 3rd is really bad for the trans?

I've had the RMVB in the car for 6+ years with no problems as of yet

[Ghoste]

For the clutches. The issue with Mopar transmissions is the way that it applies the rear band and rear clutch both in manual low.  There is a point when shifting to second that band and clutch fight each other (am I right John?).  With some manual valve bodies, the fluid flow is routed such that only the rear band is applied.

[John_Kunkel]

Like Ghoste stated, most reverse manual VB's don't apply the rear band in 1st, so there is no wear as the band releases.

[Steve P.]

quote]

This is the first I have ever heard this. Matter of fact many racers using MVB do their burnouts starting in 2nd and shift into 3rd.  Maybe it's different for the street??

Someone set me straight...

[John_Kunkel]

Starting out in 2nd or 3rd on the street puts some extra strain on the converter and will build heat quicker, the trick is to not mash the throttle. Ease into the throttle and you won't cause any harm to the trans.

[Steve P.]

Thanks John.

So when are you going to open up that tranny school??