TF727 inspection and rebuild

oldbee

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Slow&easy is the focus on ur 1st rebuild. It will work out fine. Further experience only teaches you to bypass some stuff that doesn’t need replaced. Clutches&steels always, as long as it’s torn down. You are on an epic journey, enjoy!
 

Wietse

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Back home since yesterday and had a bit of time to go through my received parts and made some progress.
I had dismantled both clutch pistons to replace the seals, lucky me the front piston popped right in on the 3rd attempt.
Strange enough i found a metal spacer installed between the belleville spring and wave spring. Lol.
It has a little weld, i doubt if this is original.
Pre installed new steels and frictions (dry) to check the clearance, front was at .075" and the rear had .042", so i did not need any selective rings i had included in the order.
Now i got the 5 friction setup in the front!

Also got a rebuild pump, i had a quick look inside the but the body looks great with new rotors, bushing and converter seal so i put it back together as there is nothing that needs attention.

First i am in for a week of holiday with sun, beach and beers to take care off, after that will get back to it and post updates as i go.

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oldbee

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That weld spot is totally normal. Don’t worry about it.
 

Wietse

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That weld spot is totally normal. Don’t worry about it.
From what I read before is that as per year and type it should have a plastic spacer ring, that's why I wondered it could have been a home made.
But if this is normal, it's all good.
Just finding one of those things that is different than "normal"
 

Wietse

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Since i installed a new clutch pack with 5 clutch discs, do I maintain the same clutch clearance as what is stated per the book? .066" - .123" for the 440 HP, with 4 frictions and 10 springs?
Or should I change it and follow the 426 Hemi specifications of .022" - .079" which has 5 frictions from factory?
It has .075" clearance now (dry), it would be too high for my liking if I better follow the Hemi specs, in that case i rather install a thicker snap ring.
 

dvw

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I like .012"-.015" per friction in the front clutch. .060"-.070" for 5 frictions. The rear clutch can be pretty tight .025"-.040".
Doug.
 

Wietse

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I will see if i can reduce .005" - .010" on the front clutch, not sure if there is any swell to expect from the friction material?
I will soak them in oil first before final installation and see if there are any changes.

Does anyone know about this tool that supposed to be used to adjust the throttle pressure spool? (Tool C-3763)
What is the length of this piece?
I had not changed the setting of my adjustment screw, but others might have in the past and I would like to check this before putting it back in place.
 

Wietse

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What I find strange is that all (selective) plastic washers I purchased from A&A are actually thinner than the OEM fiber washers that came out of the transmission.
Axial play was already on the higher side so I guess I will reuse the fiber ones and see where the axial play ends up.
 

dvw

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The .075" you have now will work fine. Leave the throttle pressure adjustment alone.
Doug
 

Wietse

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I left the clutch clearances as is, it is will within specs anyway.
I flipped the pressure plates on the clutches to use the unused side, the shitty side on the forward clutch can be seen now.
Few things I am not sure off, IIRC the front servo had only 1 spring as below picture, I searched some documents from the Transgo kit which states the HP engines have only the small diameter spring installed without any other springs.
I am 99% sure but just to confirm this is correct?

Another thing I found when I installed the pump, I do not hear a clear "thud" sound coming from the rear clutch pack when testing with compressed air.
I removed the complete assembly and tested the clutches again on the bench with the Input shaft assembly incl. pump and both clutch packs work, when the rear clutch engages it lifts the upper assembly a little.
When installing everything in the transmission I feel not comfortable all clutch frictions are fully in, though all teeth are perfectly aligned when i remove it, the assembly feels a bit wobbly and does not drop in snug.
Even with the pump installed and the bolts hand tight the input shaft has a little wobble and has no axial play, so something is not seated correct.
The lugs on the forward band drum are just over fully engaged with the gear shell, i see on most pictures and video's online it is somewhere halfway in instead.
I guess this causes the rear clutch not to function properly and gives the issues with the input shaft, i got fed up and hungry so i left it for today, just still wondering where it is hanging up.
As I said it seems like all clutch plates are aligned and engage.

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Wietse

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I had removed the pump and input shaft assembly again and tested both clutches again, they do work both of them.
The rear clutch does not make the "clunk" sound the forward one does, guess due to the belleville spring it is more smooth and gentle.
All installed and after some playing with the fiber/plastic washers I ended up with an axial play of .038", the minimum as per the book is .037" so it's a tight fit. (my other 727 shop manual says .036")
From what i read is that it is better this way and i have no thinner washers anyway.

Is it normal the input shaft has a little radial play? It does not sit really centered (see picture) but i can push it around in the stator shaft quite easy by hand.

Both bands i adjusted by tightening snug and and back off by 2 turns, this is as per the TransGo kit instructions.
I had not socket that fit the adjuster to use the method with the torque wrench, but it is quite obvious when it turns snug.

The normal fill is about 6 quarts of fluid, right?
I think this MP type oil pan adds about 2 quarts, so about 8 quarts total. (7.6 liter, it sounds like a lot of oil)

Blasted and painted the oil pan, letting it cure overnight and hopefully tomorrow i will put the tranny back in the car.

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Wietse

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Tranny is back in, hope all is installed well.
Still have to connect everything, selector, k/d lever, drive shaft, etc.
I just ordered a new set of U-joints as well.
I was under the impression there are 2 different ones but both measured the same which are 7290 size.
Probably will change them next winter season, time to drive the thing instead of working on it while the weather still allows.
I have my new Borgeson steering box, rebuild tranny and new converter to test and hopefully it is improving driving quality over the old setup.
 

62 Dart Convertible

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Tranny is back in, hope all is installed well.
Still have to connect everything, selector, k/d lever, drive shaft, etc.
I just ordered a new set of U-joints as well.
I was under the impression there are 2 different ones but both measured the same which are 7290 size.
Probably will change them next winter season, time to drive the thing instead of working on it while the weather still allows.
I have my new Borgeson steering box, rebuild tranny and new converter to test and hopefully it is improving driving quality over the old setup.
Fingers crossed all goes well Wietse. Great thread here that gives me info and confidence if and when I decide to pull my 727 and give it a once over.
 

Wietse

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Did a quick test drive just now. It does upshift up to Direct, but when stopping it does not downshift.
After a short full standstill it stays in Direct.
I had tested the governor pressure with a digital test gauge on the respective test port but it does return to zero when keeping the axle static with the brake and the tranny in D.
Any other things that may cause this, so far I only found the thing about the governor pressure that could cause this.
 

Wietse

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After some more reading on the web, most say the throttle pressure (k/d mechanism) might not be adjusted properly.
I had set it as i always do, carb at WOT and have the linkage all the way to the back with a little slack.
Upshift are later compared to before, which does indicate higher throttle pressure, which could be since the TF-2 Transgo kit installation.
Could it be the throttle pressure is too high at idle? To me it should be the other way around and the throttle pressure should force it to downshift.

Since the upshifts work, throttle pressure increases as speed is increased (only checked up to around 30-35 mph with the car lifted off the floor) and seen 25-30 psi.
Slowing down and holding the rear axle on the brakes while in drive the pressure drops to "0".

Other thing mentioned is the selector linkage adjustment, though i do not see how this could be causing this, could the selector valve spool be in a position other than the rooster comb forces it which causes pressure to leak "the wrong way"?

If not any of the above i guess i need to battle my way back into the tail housing to check the governor, i had it apart and cleaned it all out and did not find anything abnormal, all parts would move freely.
 

dvw

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Do you have the spring on the throttle pressure linkage holding it tight against the carb stud? If not the throttle pressure valve may not be seated at idle. It is possible for the manual valve to be misaligned. Alignment is mentioned in the Trans-Go instructions. Though I've never found one very far off. The Trans-Go tech guy is very good if you need to call him.
Doug
 

Wietse

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Thx for the tips dvw.
The selector lever (column shift) it pops in place if selecting D so i assume the selector lever sits ok.
I think the internal adjustment for the throttle valve might be off a little.
Return spring is installed, first i re-adjusted the throttle valve as per book but found 1-2 and 2-3 shift happen almost together. So i went back to the WOT type adjustment but the 2-3 shift became very harsh and both shifts late. So i backed it off again and now it is downshifting. I hooked up a gauge on the line pressure and found the following.

Idle in P: 0 psi
In Drive (standstill): 110 psi
In 2nd (standstill): 100 psi
In 1st (standstill): 90 psi

During cruising in D (3rd gear) it is at 140 psi, when stopping it drops to 110 and will take off in 1st gear again and upshift short and firm through all gears.
Hitting it a bit increases pressure, i seen just over 150 psi around half throttle in 3rd.
 

dvw

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Call or Email the Trans-Go tech line. They know their settings and pressures.
Doug
 

Wietse

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I installed the TF-2 TransGo kit.
This has a different spring and adjustment for the pressure control so pressures are higher then original. I will keep test driving it for some time and make any adjustments on the throttle pressure to see if/what changes for the better.
It seems to shift ok, short but firm.
The shifts are still a bit later then before the overhaul, i think this is due the different balancing now between line pressure and governor.
I like the little later shift points anyway, before they were too early for my liking.
I will see to contact Transgo and see if i can get some feedback from them.
 

oldbee

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I seem to remember emailing Gil Younger(original owner?) way back when, with kinda same problem (while racing). We couldn’t figure it out, so went with full, reverse manual v-body soon after. Sorry, not much help.
 
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