[Graham Shortreed (Transma]

I came across some technical information today on the TF727. It has to do with shift kits and how they should function. So with your permission, here goes.

Many think that the harder a shift feels, the better the shift is, and how it adds to the performance and durability of the transmission. This thinking is correct, providing the stiffness that is being felt is not being caused by interferance or overlap with the gear that is being changed.

There is a great amount of overlap on the TF727 during the 2-3 shift. Overlap by the way, is the time the transmission is literally in two gears (in this case, 2nd and 3rd )at the same time. Overlap is a major contributor to band and clutch wear in the 727. This overlap is often mistaken for firmness, when in reality, it is shift stiffness. When you eliminate overlap, friction is reduced, and the result is an improvement in performance and reliability. You will find that when you eliminate the overlap condition, the 2-3 shift may feel less firm. The condition is ok, provided you have installed the shift kit correctly, and your throttle and band linkages have been set as instructed. Your aim on the TF727 should be a smooth, QUICK gear change that feels kind of loose under light throttle. This information applies mainly to street driven vehicles that have been slightly modified. Transmission that are going to see very high horsepower, and are going to be used strictly at the race track are another matter, and I don't want to get into all the tricks and high dollar modifications and parts that are in a race transmisson.

Another thing that should be pointed out, is you MUST follow the instructions in any shift kit exactly. Too many times, I've seen good valve bodies ruined because someone thought he knew more than the maker of the kit. If your not an automatic transmission mechanic, or don't have a complete understanding of the hydraulics of an automatic transmission, don't try and reinvent the kit you've purchased.

I hope this information is of some help to the group, and as I find more hints/kinks that I think the group can make use of, I'll pass it along. I've got some good information coming to help you select the CORRECT high stall converter for YOUR application in YOUR Challenger.

[Jeff Maxwell (Redchalleng]

Graham, I can see why Transman is a good name for you. I got a lot of info in this short posting. Thanks!

I have an application question as a follow up. My car was a 318 car, but I sold it and a 340 was installed using the same 904 tranny. Now that I've bought it back (and like the Shaker hood) I don't like the 904 hooked up for two reasons. It shifts hard and the kickdown to second doesn't work. You've solved the hard shift question with your info above. Yet it also upshifts different (also hard) than it ever did, which is why I've got to watch every stop I make. Is there a linkage kit available to allow the kick down from 3rd to 2nd, or should I simply go do the obvious thing and get a 727? It is the right thing, just the expensive thing I'd kind of like to avoid. I don't race the convertible, rather drive the wheels off it. 4k miles this year, which will be low to average of my past use.

[Graham Shortreed (Transma]

Jeff, I don't know if there is any difference between the linkage on a V8 318 OR 340 or a 904 or a 727, but I'll see what a builter I know can tell me. Some of your problems may be related to the transmission starting to fail. If you can, drop the oil pan and see if there is any excessive debris in the pan, and also check the oil is black and has a pungent odour about it.
I personally think the 727 is the better choice, but at work, we are in the development stage of making an aluminum drum for the 904, that will be beta tested in a SS/AA Hemi 'Cuda. From what I've been told the 904 properly done up ( that is spend lots of $$) will hold up to just about anything.
I've got another hint for those of you that don't put a lot of miles on your cars. Don't use the stock dacron material transmission filter. Use the brass screen type. When I serviced the 727 on my Challenger recently, the dacron filter was plugged up with a gooey muck. The builder at the shop I was at ( by the way a Mopar Guy) said that the muck on the filter was not uncommon. The reason is the dacron filter doesn't drain back as completly as the brass screen type. No problem on a daily driver, but a possible problem on cars that don't get a lot of mileage on them.

[Graham Shortreed (Transma]

Jeff. I just got off the phone with my rebuilder buddy. He says that to the best of his memory the linkage was the same. He feels that the only area there might be a difference would be if one was a two barrel carb and the other a four barrel carb. Other than that, he says there should be no reason he can think of for the linkages to be any different.
Hope this helps.

[Jeff Maxwell (Redchalleng]

Graham, you guessed it. The 318 was a 2bl and of course the 340 has 4 bl. Fluid is the right color, I'll ask the previous owner about the filter. He isn't the one who switched it, but he knows a lot about Mopars as he rebuilds them for a living.

Graham, THANK YOU for the input! I'm at the other end of the performance curve when it comes to what you're used to. Mine sounds much nastier than it is, as my 300M would leave it in the dust. My job is to educate others about Challengers by putting smiles on their faces as I drive mine as much as possible with the top down. The looks you get are priceless, which is why I want the ride to behave. 727 is probably the best answer. Thanks again!

[Graham Shortreed (Transma]

My pleasure Jeff.
Anytime I can help with the little knowledge I've got, I will.