TF727 inspection and rebuild

[66Satellite47]

All those seal rings for the servo's and shaft come with the repair kits, right?

Indeed, like i said it was probably due to the throttle linkage or the piston seals are fried. (maybe the pump is also aiding this due to lack of pressure)
The 440 in front of it is not a stock one, i never abused it but it is driven hard at times.
We will see when i get to it again how the piston seals will look when they come out.
I am waiting for a shop here in Europe to respond on my email if they have a front pump housing for me, if not i need to include it in the order i will place from US.

The seals & seal rings should come with the kit. If I recall using the teflon seal rings for the reaction shaft were a separate upgrade from Cope the standard style were in the kit. Sometimes those clutch piston lip seals can be a real pain. Much care and patience is required.

 

[dvw]

Installing the front clutch piston is the trickiest part of the job. I put a large zip tie around the outer piston seal. Then set it in the freezer for 1/2 hr. Slide the zip tie off. Lube it up and press the piston down into the drum. Work around in a circular motion. A hammer handle is a good tool to use to push down on the piston. Be patient and keep going around. Once it starts to drop you'll feel it. either Teflon or steel rings work fine. If you use Teflon grease the sel groove to retain the ring in the groove. You don't want it sticking out where it can catch during install.
Doug

 

[Wietse]

I read some more about that front clutch piston indeed that this is a PITA.
I like your tip of putting it in the freezer and let the rubber get hard while compressed.

After some digging I found in the manual regarding the adjustment for the throttle valve.
I had mine loose but installed it back as it came out, doesn't mean it is right though.
The tool they use looks like a simple spacer that is installed against the spool and pushed all the way in, from there the tab on the linkage require to contact the screw head.
Anyone knows the dimension of this tool?
If this is know it is easy enough to check it.

 

[66Satellite47]

Installing the front clutch piston is the trickiest part of the job. I put a large zip tie around the outer piston seal. Then set it in the freezer for 1/2 hr. Slide the zip tie off. Lube it up and press the piston down into the drum. Work around in a circular motion. A hammer handle is a good tool to use to push down on the piston. Be patient and keep going around. Once it starts to drop you'll feel it. either Teflon or steel rings work fine. If you use Teflon grease the sel groove to retain the ring in the groove. You don't want it sticking out where it can catch during install.
Doug

dvw, again great advice. I've never used the zip tie/freezer method on the drum piston, but sure sounds good.

 

[Wietse]

This is confusing me, Trans Parts Online their parts are significantly cheaper compared to CRT, how come?
Do you still pay a core fee that is not mentioned? Even then the prices with CRT are much higher.
The other thing is, flex or solid front band, what is the best choice? HP rating of my 440 would be 450-500 hp.
CRT now has my year complete pump in stock, which is tempting as I do not have to fiddle with the bushing.
The other option is a used pump body (incl. new rotors) from Trans Parts Online...refurbished or used....I guess the refurbished one is the safer option here.

 

[dvw]

I've used the trans parts online stuff plenty. The clutches and bands are name brand. Or you can purchase Alto reds. No need for Altos with your combo. I've seen plenty of different failures with lots of different stuff. But I've personally never taken apart a trans with a broken flex band. Pump bodies are seldom worn. If your reaction shaft support is good, I probably have one. Don't have any idea on shipping though.
Doug

 

[66Satellite47]

If Doug says it's good I'd believe him. Cope's prices may a bit high on some things. Again I've use both aftermarket solid and flex bands in much higher HP/torgue applications than you have, never a problem. John Cope told me he typically uses a flex band. That's what I have used in my last few customers 727's.

 

[Wietse]

I trust the both of you on the tips and advises, don't worry.
But comparing a front flex band for example, $165 - 195 at CRT and $11,60 at Trans parts online. (CRT also has core fee, so reduces the price but still difference is huge)
That made me wonder, if price is lower it's no problem but don't want to end up with proper chinesium made parts.
I like the trans parts online as you can get so many individual parts, different thickness washers etc. so i would prefer to order from there the get a selection so I can do any adjustments on axial play if required.
Also adding some more bits and pieces as shaft seals etc. so I have some stock, when the time comes I need one again there will be one lying on the shelf.

 

[Lefty71]

But comparing a front flex band for example, $165 - 195 at CRT and $11,60 at Trans parts online. (CRT also has core fee, so reduces the price but still difference is huge)

I must be missing something here.... I see NO flex band at CRT's site for $160.00+ The only high dollar band I see there is a Red Lined Old school solid kickdown band, which is probably the best unit you can get your hands on, and not likely to be found at all at discount trans parts shops, because their supply has long since dried up. Am I seeing this wrong??

HTH, Lefty71

 

[Wietse]

I must be missing something here.... I see NO flex band at CRT's site for $160.00+ The only high dollar band I see there is a Red Lined Old school solid kickdown band, which is probably the best unit you can get your hands on, and not likely to be found at all at discount trans parts shops, because their supply has long since dried up. Am I seeing this wrong??

You are right, the one I was looking at is a red lined solid band. My bad.
CRT their flex band is $65, with an optional $25 core return but due to my location it is no point to return my old core due to shipping costs.
Still, a $65 unit or $11,60 is quite a difference, but maybe I am comparing a simple good unit with a high spec drag unit that I am not aware of.
Just want to make sure I get a good quality kit that has everything I need and will be there to survive for many years to come.

 

[Wietse]

Looks like this is going to be my shopping list, now I found the correct pump housing is no longer available so I will need another source for that.

If your reaction shaft support is good, I probably have one. Don't have any idea on shipping though.

dvw, do you have a good used pump housing you are willing to sell? International shipping will be covered by me of course.
If so, does it need new rotors or bushing? If required I can add the parts on my list at Trans parts online.

 

[dvw]

I'll check when get back. I'm racing this weekend.
Doug

 

[66Satellite47]

You are right, the one I was looking at is a red lined solid band. My bad.
CRT their flex band is $65, with an optional $25 core return but due to my location it is no point to return my old core due to shipping costs.
Still, a $65 unit or $11,60 is quite a difference, but maybe I am comparing a simple good unit with a high spec drag unit that I am not aware of.
Just want to make sure I get a good quality kit that has everything I need and will be there to survive for many years to come.

I think you have a typo there Eleven thousand is a lot for a band. Do mean eleven dollars? An eleven dollar band is really cheap. Not HP lining I suspect. I'm 99% sure I paid twice that for an OEM band in '73. Pretty sure I was paying $30+ for B&M red bands or Turbo Action birch bark bands in the late 70's & 80's. Lining materials are not all the same. Same is true with clutches.

 

[Wietse]

I think you have a typo there Eleven thousand is a lot for a band. Do mean eleven dollars? An eleven dollar band is really cheap. Not HP lining I suspect. I'm 99% sure I paid twice that for an OEM band in '73. Pretty sure I was paying $30+ for B&M red bands or Turbo Action birch bark bands in the late 70's & 80's. Lining materials are not all the same. Same is true with clutches.

Exactly, $11 for a front flex band.
Therefore I questioned the quality, but if this is strong enough for my application I should have nothing to worry.
They have another flex ban (Raybestos), which states HP and costs $26.
I can add the raybestos bands and borg warner frictions separate if the kit content is questionable.

 

[Lefty71]

Exactly, $11 for a front flex band.
Therefore I questioned the quality, but if this is strong enough for my application I should have nothing to worry.
They have another flex ban (Raybestos), which states HP and costs $26.
I can add the raybestos bands and borg warner frictions separate if the kit content is questionable.

I guess all I'd like to add here is, don't bounce back and forth too much trying to save a buck. You stated "500hp max motor"..... well, that's more than any stock production Torqueflite was really expected to handle!! So, build with that mindset, don't cheap out and create the next weak link that will cause a failure next time. They are really good trannys, but you won't regret building one to last, and handle the power. My 2 cents, play on lol.

 

[66Satellite47]

Exactly, $11 for a front flex band.
Therefore I questioned the quality, but if this is strong enough for my application I should have nothing to worry.
They have another flex ban (Raybestos), which states HP and costs $26.
I can add the raybestos bands and borg warner frictions separate if the kit content is questionable.

If it was mine I'd SURE go with the Raybestos band. I've used both some Raybestos bands and the Raybestos clutches over the years with great results, a Raybestos flex front band would produce great results. The OEM style band material is fine for the rear band. Not sure what the Borg Warner clutches are like. The last 727 I built for my 600 HP drag car used the Raybestos front clutch frictions. It came out after about 125 runs. I can still read Raybestos on the frictions. Just my experience.

 

[Wietse]

I am not trying to save money, i just want good quality parts that will last and if more expensive then so be it, no problem.
But i want to avoid buying drag race spec parts with high costs while i do not need it.
As 66Satellite47 said, Raybestos bands and clutches are good quality, so from here i would say i will use them, dvw mentioned he used the set of frictions that come in the kit i mentioned above and were found to be good quality.
I was just surprised to see the big difference in prices between several suppliers of transmission parts.
Most of the time you find that if it something is cheap it is made of Chinesium, so i want to avoid that.
If a good front band costs $11 or $60, it doesn't matter because i will buy it regardless as long as i know it's good.

But i think i get the kit and order a set of raybestos/Borg Warner frictions as well, i use what suits me and keep the other set for later project or whatever.

 

[66Satellite47]

Like I said before, I'd listen to dvw. I have no experience with the kits he has. I have used the CRT kits in the last 727's I have built which did not include bands, frictions, steels. Those were all separate. My builds were for basically race 727's. As I said, the last one had lip seals that were not quite the quality as some of my 40 year old parts in my spare parts box. Since dvw has much more recent experience than I do, I would listen to him. My best kits in the '80s were Fram, excellent seal rings, lip seals, steels, gaskets. Don't think I ever used the front frictions, no bands. I did use the Turbo Action front band and the TA frictions in my race 727's. Get parts you are comfortable with, see how they work out.

 

[Wietse]

Considering all you guys helpful reactions i will go with their high performance kit which includes Alto Red Eagle frictions, Kolene steels and Raybestos HP flex band.
Aside from that the washer kit as well, the master kit includes a full gasket kit with all gasket, seals and sealing rings to do a full sealing round.
It also includes some bushings, i added the other bushings to have a complete set, just in case.

One tip i found in several Youtube video's was that if you can find one, change the rear clutch Bellville spring for the later model ('74-up), which is more beefier/stronger. (mine shown in the picture, the "skinny" version)
Anyone has any experience on these if this would be a good upgrade, or stick with the original one?
I assume the later model being more stiff, it will require more hydraulic pressure for the clutch to engage, i already modified my valve body with a TransGo TF-2 kit which provides higher pressure if i am not mistaken.
Other thing would be that it releases the clutch faster due to higher spring pressure, which would cause less/shorter drag time on the frictions?

And 1 thing i find that i don't understand, it seems there are 2 sizes of the stator bushing ID, 1.125" and 1.175"??
They have a used pump in stock that says the bushing ID is 1.125", though a new stator bushing states 1.175" ID.
Or maybe it is a typo, but i did not find different sizes of bushings for the '68 - '71 models.

 

[66Satellite47]

Over the years, I've almost always used the early "narrow" style rear spring. Never a problem.
Not sure what sure the pump bushing difference is. All that I have used for many different year pumps are all the same. No difference between '70 & earlier and the later pumps. The different bushing is in the front clutch drum and pump reaction shaft.