727 missing spring

[Andrew vanman87]

So I've been working on 71 Newport 383 ... I have two big block 727s I recently removed one because the front pump was making tons of noise and it was no longer getting third gear... So I removed it and installed another one that I had found... It's biggest issue is it seems like it's just been sitting for years on end .. long story short I installed that one but could not get any gears to engage...
I dropped the valve body down and found out the selector on the valve body was not functioning ( the reason why I wasn't getting any gears)
I did notice ( both transmissions) are missing spring on both transmissions ( accumulator spring).

I thought it was odd that both transmissions didn't have that spring..

My question is why? And should I try to find a spring for it? What will happen if I install it without the spring?

 

[Oldmanmopar]

It is there to cushion the shift. Many would remove it to shorten 1-2 shift and make the shift more crisp. But a solid prop should be put in place of the spring.

A-727 Accumulator Blocker Rod 727-22841BR

 

[Vaanth]

My question is why? And should I try to find a spring for it? What will happen if I install it without the spring?

The accumulator controls the hydraulic pressure on the apply side of the kickdown servo during the
1-2 shift. It provides cushioning for the kickdown band application at any throttle position. The spring affects the cushioning.

Some shift kits, or aftermarket valve bodies, specify leaving the spring out, or leaving it out plus adding a blocker rod to increase 1-2 shift firmness. The spring is sometimes just left out by itself hoping to increase 1-2 shift firmness. It might affect the firmness in some cases, but can affect engagement harshness into gear.

There is debate on whether its absence is beneficial or harmful in a stock transmission. I typically install them if the transmission is stock or follow what the shift kit specifies in those I build with a kit. For shift kits, I use Trans-Go or older Fairbanks kits.

 

[Andrew vanman87]

The accumulator controls the hydraulic pressure on the apply side of the kickdown servo during the
1-2 shift. It provides cushioning for the kickdown band application at any throttle position. The spring affects the cushioning.

Some shift kits, or aftermarket valve bodies, specify leaving the spring out, or leaving it out plus adding a blocker rod to increase 1-2 shift firmness. The spring is sometimes just left out by itself hoping to increase 1-2 shift firmness. It might affect the firmness in some cases, but can affect engagement harshness into gear.

There is debate on whether its absence is beneficial or harmful in a stock transmission. I typically install them if the transmission is stock or follow what the shift kit specifies in those I build with a kit. For shift kits, I use Trans-Go or older Fairbanks kits.

yea i thought it was odd both transmissions didn't have one .... i am not sure the valve body is stock or not i been debating if i should by one or not ... i also didn't want it to destroy anything by not having it... would this be something someone would do to with a stock valve body ? Cheap way to make the shifts harder ? i could put a rod in there but wouldn't that make it shift harder ?

 

[Vaanth]

yea i thought it was odd both transmissions didn't have one .... i am not sure the valve body is stock or not i been debating if i should by one or not ... i also didn't want it to destroy anything by not having it... would this be something someone would do to with a stock valve body ? Cheap way to make the shifts harder ? i could put a rod in there but wouldn't that make it shift harder ?

Yes, leaving out the spring is what some try with a stock valve body to firm shifts, and it is essentially free if one is already into the transmission. Results vary whether it does firm up the shift or not.

I'm not a fan of the blocker rod, although its use can increase the firmness, and harshness, but it also increases loading on other components, so if it is used, it should probably only be used as part of a system of components intended with its use. A billet accumulator piston is a wise idea. Harshness is not necessarily firmness though...but Mr. Gil Younger could have explained that far better than me.

I'm not a transmission builder, but I've rebuilt 30-40 Torqueflites over the years and I've used a blocker rod twice. Once for a friend's transmission in a 383 Road Runner in the 80s. It was built with all B&M Transkit, etc, and used the blocker rod. Overall it worked well, but it was a complete package. The other is in my 360 Ramcharger using a mix of stock parts, Chrysler cast iron band, Raybestos frictions/steels, old style Trans-Go TF-2 (the one with all the replacement valves), front clutch aftermarket 15 spring kit, deep pan, and some other tweaks. It performs great, but the 1-2 upshift is overly harsh.

 

[413]

It is a backyard hack, "toss that spring and it's better".
The blocker rod goes under the piston.

It works fine without the rod or the spring.

I like to leave the spring in on a stock trans.

I can send you one of you want to have it.

 

[j par]

I use like a 1/2 inch socket. Then grind it down there to keep it lifted up to the top...

 

[j par]

I have only rebuilt a couple of these, and most of them are for some kind of performance.. and I only rebuild them for myself..
Having bought rebuild kits and definitely the transgo two shift kit. I have old instructions and use some of what they you say to do... And some of these old tricks and do my own thing, but I only have myself to blame, but i've had good results...
There's a couple of those little passageways they want you to drill out a little bigger, according to how hard you want it to shift and also a little pressure adjustment, nothing too extreme..
Again, I am making no recommendations, here.I'm just telling you, i've done a few things and had good results...
I have no long term data...

 

[RustyRatRod]

For a high performance Torqueflite, I just look at a stock Hemi transmission and copy that. They used an accumulator spring. There are other things besides leaving important parts out to firm up shifts. Chrysler did it.

 

[GTX JOHN]

60 years ago, I always remove the spring
when I was teenage Kid. It never seemed to hurt the trans
and did shift harder 1/2. I also turned up the line pressure
some.

But there are better ways to skin a Cat!

 

[Andrew vanman87]

Ok I think I'm going to leave the spring out... Since it's not going to be detrimental to the life of the transmission.. I had to replace the valve body in the transmission in my car anyway and I just noticed both transmissions didn't have that spring

 

[Andrew vanman87]

update....The c-clip dropped out of the for the shifting linkage hooks on... lost the ball and spring as a result... Which was the reason why my 727 was not getting a single gear... Recently swapped out the valve bodies from the other 727 I had laying around... Fix the problem really the only thing I noticed is that the transmission seems to if smoother than most 727s or 904s in my experience... I did adjust the bands to factory spec with a torque wrench... But shifts rather smoothly even without the spring

 

[71Demon540]

Happy to hear you found the issue. For what it’s worth, I don’t build a single transmission using the accumulator spring. I use a blocker rod on every unit including street transmissions. Not using a spring or blocker rod and letting the accumulator “float” is just fine.

 

[Andrew vanman87]

Happy to hear you found the issue. For what it’s worth, I don’t build a single transmission using the accumulator spring. I use a blocker rod on every unit including street transmissions. Not using a spring or blocker rod and letting the accumulator “float” is just fine.

Okay yeah I mean the transmission shift smoother than my Lexus however I didn't know that would be the outcome leaving the spring out ... I was a little bit worried about it being detrimental to the health of the transmission but it looks like that's not the case.. next time I do one of these I might put a rod in there... But for cruising around town in the Newport I think it's fine the way it is I don't need any harsh shifting for the land yacht

 

[j par]

Happy to hear you found the issue. For what it’s worth, I don’t build a single transmission using the accumulator spring. I use a blocker rod on every unit including street transmissions. Not using a spring or blocker rod and letting the accumulator “float” is just fine.

It can't get cocked sideways without support? ..

 

[j par]

I don't think the object is to give it a harsh shift, but a more quick and positive shift, not letting the clutches slip and wear out, but just making them grip quicker with less slippage...

 

[71Demon540]

It can't get cocked sideways without support? ..

It can get cocked sideways even with the spring from what I’ve read.
My preference is simply the blocker rod for a few reasons but mainly it’s one less part inside to fail or malfunction. I’m typically dealing with high performance units for drag racing the street units I’ve built, no one has complained about too firm of a shift 1-2 or too harsh of engagement when going from neutral to 1. I also know the chance of an issue with the accumulator piston is very low with the blocker rod. So I just stick with what I know has worked for me.