727 Quest. 2nd to 3rd shifts late. Semi-long

Posted By: WyleECoyote

727 Quest. 2nd to 3rd shifts late. Semi-long - 04/23/10 01:50 AM

Place it in drive.
Accelerate;
1st to 2nd shifts at about 35/40 mph.
2nd to 3rd shifts at 65 mph.
It really labors and hangs until you hit 65.

Okay - so lets go back to 1995...
I rebuilt a 727 for a 440, 10:1, .550 roller.
I used an article from one of the Mopar Mags;
Valve body: threw out some of the check balls and drilled out a hole here and there a little larger.
Accumulator Spring: I'm pretty sure I tossed it.
Line Pressure: I remember the article had me make a gauge out of cardboard and adjust the spacing to the gauge.
Torque Converter: 2500 stall.

This drive train never made it into my Road Runner; job change forced me to throw it in my 84 Crew Cab Dually with 4.10 rearend, to get from Utah to Tennessee. WHAT A BLAST OF A ROAD TRIP THAT WAS!!! Transmission worked great for running it hard.

Fast Forward to 2010: I never drove the truck after I got here. Now I'm at a point where I'm ready to play with the truck and drive it. I pulled out the built 440 and put in a bone stock 72 440 and a stock torque converter.

Finally - the question:
Of the 3 mods I did; valve body, accumulator spring, line pressue - which one mod, or combination there of, makes the late shifting point from 2nd to 3rd at 65 mph?

I'd love for the 2nd to 3rd shift point to be lower - like around 50 or 55.

Thanks in advance for the inputs!

Posted By: 1_WILD_RT

Re: 727 Quest. 2nd to 3rd shifts late. Semi-long - 04/23/10 02:06 AM

Shorten the kickdown (throttle pressure) linkage about 3/16th of an inch

Posted By: WyleECoyote

Re: 727 Quest. 2nd to 3rd shifts late. Semi-long - 04/23/10 02:12 AM

Do you mean so that at WOT - the kick down linkage still has 3/16-inch before it is fully engaged?

Posted By: 1_WILD_RT

Re: 727 Quest. 2nd to 3rd shifts late. Semi-long - 04/23/10 02:15 AM

I mean how ever it is currently set-up shorten it 3/16"... It might take 1/8" or 1/4" but shorten the link & drive the vehicle...

Posted By: WyleECoyote

Re: 727 Quest. 2nd to 3rd shifts late. Semi-long - 04/23/10 02:17 AM

Copy that. Will certainly try that tomorrow! Thanks for the suggestion!!

Posted By: John_Kunkel

Re: 727 Quest. 2nd to 3rd shifts late. Semi-long - 04/23/10 10:40 PM

Quote:

Place it in drive.
Accelerate;
1st to 2nd shifts at about 35/40 mph.
2nd to 3rd shifts at 65 mph.
It really labors and hangs until you hit 65.

How much throttle are you using?

Quote:

Of the 3 mods I did; valve body, accumulator spring, line pressue - which one mod, or combination there of, makes the late shifting point from 2nd to 3rd at 65 mph?

The VB mods you did will have no effect on upshift speed.
Tossing the accumulator spring has no effect on any shift.
Raising the line pressure will make the shifts later.

Posted By: WyleECoyote

UPDATE: Re: 727 Quest. 2nd to 3rd shifts late. - 04/30/10 01:26 AM

So "yesterday" finally came and I played around with the truck...
I undid the kickdown linkage and tied it forward.
Went for a drive and it shifted GREAT!
2nd to 3rd happened repeatedly at 46 mph!
The shifts were firm (nice) but both 1st to 2nd and 2nd to 3rd happened at what seemed like "normal" speeds.
So now, to I reconnect the kickdown and keep drilling holes in it to shorten its travel???

Posted By: John_Kunkel

Re: UPDATE: Re: 727 Quest. 2nd to 3rd shifts late. - 04/30/10 05:50 PM

I'll ask again, how much throttle are you using to get those shifts?

If it's light throttle the shifts are way too late for having the lever tied full forward. With the lever full forward and light throttle you should be in top gear at 20 mph or less.

Posted By: WyleECoyote

Re: UPDATE: Re: 727 Quest. 2nd to 3rd shifts late. - 05/01/10 12:51 AM

Sorry John - I missed your question earlier. Yes, its a light throttle - I'm just trying to drive it like an old man and its shifting from 2nd to 3rd that late. I had no idea it should be into 3rd by 20. Its been so long since I've driven one of my un-altered cars that I'd forgotten what the shift feels like....

Posted By: John_Kunkel

Re: UPDATE: Re: 727 Quest. 2nd to 3rd shifts late. - 05/01/10 09:29 PM

If it's shifting that late at light throttle with the linkage off there's something wrong inside. If you move the TP lever to the rear by hand is there some free travel before you feel spring resistance?

Posted By: WyleECoyote

Re: UPDATE: Re: 727 Quest. 2nd to 3rd shifts late. - 05/03/10 12:22 AM

John - no, there is no free travel before there is spring pressure. It is immediate. As soon as I push back on it - there is spring pressure. What's all this mean?

Thanks a ton so far!!!

Ron

Posted By: John_Kunkel

Re: UPDATE: Re: 727 Quest. 2nd to 3rd shifts late. - 05/03/10 09:08 PM

It means there is no free play between the kickdown valve and the throttle lever cam as there should be. With the valve depressed at idle the trans thinks you're giving it lots of throttle as soon as you take off and that's what's delaying the shifts.

You need to remove the VB for a look see.

Posted By: WyleECoyote

Re: UPDATE: Re: 727 Quest. 2nd to 3rd shifts late. - 05/04/10 01:13 AM

Okie dokie - time to break out my factory service manual and get re-familiarized with these parts of which you speak...

Then -

Thanks John - I really appreciate this.
I'll send you your beverage of choice when we're done!

It might be a week or two before I get this task on the wife's docket - but I'll be sure to update all.
Thanks John and Moparts!

Posted By: WyleECoyote

Re: UPDATE: Re: 727 Quest. 2nd to 3rd shifts late. - 05/18/10 01:10 AM

John - (and others)

As I thought about your comments, I decided to look further into the kickdown linkage adjustments. Crawl under the truck with me and go to the kickdown lever on the trans: the rod that comes down from the engine has a "slide-adjustment" block bolted to the rod with a spring behind it. Well it was adjusted "OUT" towards the rear of the truck. This had the kickdown lever on the trans engaged by about 1.5 inches. I undid the rod/block and the kickdown lever sprung forward towards the radiator. As I examined it, it had the free travel you mentioned before it had spring tension. I removed the spring from the rod and slid the block forward and that allowed it to align with the kickdown lever when it was forward.
I now have a 1st to 2nd shift at about 18 and a 2nd to 3rd at about 30.

Considering the 4.10 gears, I think this is a good shift point. It feels a little "long/late" compared to my Superbee, but I'm guessing it [the Bee] has 2.91 gears or so.
All in all, thanks to you and others, I've brought the shift point !WAY! down!
I think I'm pretty satisfied at this point...

Unless you think it can still come down some???
Thanks again everyone!!
Ron

Posted By: John_Kunkel

Re: UPDATE: Re: 727 Quest. 2nd to 3rd shifts late. - 05/18/10 06:50 PM

That's still a little late especially with 4.10 gears but if it's OK with you leave it as is.

The correect adjustment procedure for that type of linkage is to loosen the adjustment bolt so that the rod slides freely through the swivel, then push both the rod and transmission lever full forward and then tighten the bolt. Be sure the carb is at warm idle setting with the choke full open.