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DIY 727 build questions

Posted By: Brad_Haak

DIY 727 build questions - 07/20/22 06:11 PM

1. What are the "must have" special tools for teardown & reassembly of a 727?

2. What's a reasonable ballpark price for a core BB 727 in the current market?

3. Do you have any preferred suppliers for these tools and/or standard & performance parts for the job?

Thx
Posted By: GY3

Re: DIY 727 build questions - 07/20/22 06:42 PM

1. Clutch spring compressor. Two vice grips with the wide jaws will do in a pinch.

2. Around here a BB cased 727 will run you about $150.

3. I like the Transtar kits but upgrade to the kolene steels and Alto Red clutches if it's for a higher horsepower build. I used to get locally from a supplier but now just go online and get them.
Posted By: 440Jim

Re: DIY 727 build questions - 07/20/22 07:06 PM

Here is my thoughts on "must have" tools for a simple disassembly and reassembly for freshen-up, not an overhaul with bushings, etc.

0. Something to pull the front pump. Slide hammer, chain, etc.
1. Feeler gauges for setting the clutch pack clearance.
2. Dial indicator to measure the input shaft endplay before and after.
3. Snap ring pliers to take the output shaft snap ring off/on.
4. Expander pliers to open the tail housing bearing retaining ring to get the tail housing off. But a couple screw drivers can get it done.
5. Front clutch compressor to change the seals (and maybe the springs). A home made one gets the job done (pic).

Attached picture 727_clutch_compressor.jpg
Attached picture P818_Clutch_spring_compresser.JPG
Posted By: RTSE4ME

Re: DIY 727 build questions - 07/20/22 08:42 PM

I use the same tools as Jim except slide hammers and front clutch tool. For the front clutch I use the center of a steering wheel/ damper puller with a bench vise.
I bought everything from CRT
Posted By: Blusmbl

Re: DIY 727 build questions - 07/21/22 01:27 AM

Originally Posted by GY3
1. Clutch spring compressor. Two vice grips with the wide jaws will do in a pinch.

2. Around here a BB cased 727 will run you about $150.

3. I like the Transtar kits but upgrade to the kolene steels and Alto Red clutches if it's for a higher horsepower build. I used to get locally from a supplier but now just go online and get them.


This might be a can of worms but I'm starting to research what I'd need to rebuild my 727 in case I hurt it on the spray this year. For 600-ish horsepower @ 4300 pounds, besides the steels/clutches you mention, is there anything else that's a must do? Billet front drum? I've already got a Cheetah RMVB that doesn't have low band apply but I never pedal the car in 1st gear and only downshift to 1st if it's creeping along, and also am trying not to do burnouts in 1st gear either.
Posted By: AndyF

Re: DIY 727 build questions - 07/21/22 02:14 AM

Originally Posted by Brad_Haak
1. What are the "must have" special tools for teardown & reassembly of a 727?

2. What's a reasonable ballpark price for a core BB 727 in the current market?

3. Do you have any preferred suppliers for these tools and/or standard & performance parts for the job?

Thx


Move back to Oregon. I have 727 cores, spare parts and all the tools. I'll even let you borrow my 727 stand.

Attached picture DSC_1691 (Large).JPG
Posted By: Brad_Haak

Re: DIY 727 build questions - 07/21/22 12:15 PM

^^^ You're killing' me, Andy laugh2

-------------------------------------------------

A brief glance at the local ads shows I can pick up a BB 727 core (or 2) for about $200 +/-. Are there better years or versions to look for, if there's a choice?

Never done a trans, other than what little I did to help 440Jim when he went through mine 20+ years ago. People say "they're easy", but I look at the book I have and still think I might get lost inside one... lots of little sh!t to deal with. confused

-------------------------------------------------

FWIW, one of these CRT kits appears to have just about everything that's been upgraded in my current trans, should I want to build something pretty much from scratch ==> CRT DIY 600-700 HP kit
Posted By: 440Jim

Re: DIY 727 build questions - 07/21/22 03:12 PM

Originally Posted by Brad_Haak
A brief glance at the local ads shows I can pick up a BB 727 core (or 2) for about $200 +/-. Are there better years or versions to look for, if there's a choice?


I prefer the 1971 and newer. I have seen '77 and '78 van/truck BB 727's with the older 2 spring kickdown servo.
Originally Posted by 440Jim

1970 & earlier:
- narrow bushing high clutch drum with 2 oil ports 180° apart.
- Flat snap ring used in high clutch drum
- corresponding narrow bushing journal on front pump reaction shaft support and large oil port for high clutch piston.
- Solid kickdown servo piston with 1 or 2 springs
- Different piston lip seal dimension wide vs. short lip
- 1966 & earlier had 19 spline input shaft
- 1966 & earlier had 10 spring peg high clutch piston.

1971+:

- Wide bushing high clutch drum with 1 slotted oil port.
- corresponding wider bushing journal on pump reaction shaft support and smaller oil port for high clutch application.
- Controlled load kickdown servo piston with oil cushioned inner piston with only 1 spring (shim solid or plug the side hole in the piston)
- Flex bands introduced
- Wavy snap ring in high clutch drum
- 1967+ had 24 spline input shaft
- 1976+ had 37.5° pressure angle on front planetary for improved strength
- Part throttle kickdown valve added
- Lock-up converters 1978+
- Smaller orifices in VB to feed servos with less harsh shifts
- 15 spring peg high clutch piston

Many more differences......
My notes show the planetary spline pressure angles were:

'62 to '75: 45º
'76 to '93: 37.5º
'94 and later: 30º
Posted By: AndyF

Re: DIY 727 build questions - 07/21/22 03:23 PM

Unlike engines, Mopar actually improved the 727 over the years so generally the new stuff is much better than the older "classic" stuff. A late 70's truck or van transmission is a pretty good core and they are typically less expensive than a muscle car core. Just watch out for the lock up ones since they used some special parts that you probably can't use in a performance trans.

I used to be afraid of opening up a transmission. The first 727 that I rebuilt took me about a week to do. I read the book, took some parts off, read the book, took more stuff apart, etc. The second trans took about a day to rebuild and then the third one took half a day. Most of the time is spent cleaning parts since used transmissions can be filthy. Not sure what a pro can do, but once I got familiar with a 727 I could put one together in a couple of hours if all the parts were clean. I'm sure a pro can do it faster than that. They are actually easier to put together than an engine since you don't have to measure as many things. Once you figure them out it is more like putting drum brakes on a car. Lots of springs and frictions and little clips.
Posted By: 440Jim

Re: DIY 727 build questions - 07/21/22 03:26 PM

2-cents. twocents
- Shim the rear servo so the cushion spring is almost solid (Brad, I likely did this to yours already or billet)
- A billet (1-piece solid) rear servo with a stronger retainer and stiffer spring is good with low band apply. (See Randy in parts forum).


Attached picture Rear_Servo_shimmed.jpg
Posted By: AndyF

Re: DIY 727 build questions - 07/21/22 03:33 PM

I checked over the 727 in my Duster before the season and it only took a couple of hours to pull valve body, pull the pump, open it up and take a look. Everything looked good so I put it back together and checked the end play. Piece of cake once you have a few tools and know the drill.

Attached picture DSC_3520 (Large).JPG
Attached picture DSC_3524 (Large).JPG
Attached picture DSC_3529 (Large).JPG
Attached picture DSC_3531 (Large).JPG
Posted By: Brad_Haak

Re: DIY 727 build questions - 07/21/22 03:41 PM

@Jim - We (you) put in one of RandyJ's billet servos and the HD spring that came w/ the JW valve body that went in originally

@Andy - Thanks for the words of encouragement... everything "new" is "scary"

@Anybody - Found this a few minutes ago that should be helpful as I begin to search for a core: http://mymopar.com/downloads/transguide.pdf
Posted By: moparx

Re: DIY 727 build questions - 07/21/22 04:52 PM

the monroe book and a FSM come in handy for things you may have forgotten.
those also show the tools needed, and gives a guy ideas on how to make his own.
just my opinion. your mileage will vary.
beer
Posted By: an8sec70cuda

Re: DIY 727 build questions - 07/21/22 05:27 PM

Brad, I'm almost done w/ my first trans rebuild on a 727 out of a 340 Duster. Everyone has always told me the same thing...they're easy to do and no reason I shouldn't be doing it myself. The guy that's always done mine is semi-retired now so he only does a fraction of what he used to...I figured I need to learn how to do it. Taking it apart and reassembling it is the easy part. Knowing what to look for as far as wear patterns and all that is what worries me.

I have the Munroe book https://www.amazon.com/Torqueflite-727-Transmission-Handbook-HP1399/dp/1557883998/ref=sr_1_2?crid=35OEIW119E2MM&keywords=how+to+rebuild+727+transmission+book&qid=1658424307&sprefix=how+to+rebuild+727+transmission+book%2Caps%2C74&sr=8-2

and I've watched this video about 20 times, lol. https://www.youtube.com/watch?v=nmYAL7i32fA

My trans guy has helped me out w/ some questions I've had too.

The only thing I had to buy was a clutch spring compressor. Got one off amazon for about $50. It looked nice and I didn't want to bother trying to make my own.
If you have a couple of different decent snap ring pliers and some feeler gauges, you should be good.
Posted By: racerx

Re: DIY 727 build questions - 07/22/22 02:26 PM

Taking it apart and reassembling it is the easy part. Knowing what to look for as far as wear patterns and all that is what worries me.
^^^ This is what I'm going through now work (short story) had a transmission that lost reverse at the end of last year, and when came time to tear it down i notice one of the planetary's outer gear had some uneven wear on it. Replace it with a steel planet from Cope ......we shall see how it goes work







Also there's some great homemade tools made hear up
Posted By: Brad_Haak

Re: DIY 727 build questions - 07/22/22 02:29 PM

FWIW, I have the Carl Munroe book and the FSM for reference. My intimidation factor has been reduced a good bit by the responses above. luck
Posted By: sixpakdodge

Re: DIY 727 build questions - 07/22/22 02:55 PM

I did my first 727 in 2016. I disassembled every component and rebuilt it using a variety of components from TSR, A&A, and Coan. I did buy a slide hammer, but do not remember how I managed to work around the other items listed. I tend to get creative when needed. Long story short, I drove the car for the first time on a Saturday night to work, got off Sunday morning, and went straight to the track. I made two time runs, and went three rounds. Trans is still in the car today with zero issues other than checking the band adjustment. There is no need to overthink this.
Posted By: Cab_Burge

Re: DIY 727 build questions - 07/22/22 06:34 PM

I use a 3 to 4 foot long big chain,3/8 or bigger to remove the front pump from the tranny. Remove all the bolts holding the pump into the tranny and use two 3./8 by 2 to 4 inches longs bolts with flat washers holding them into the chain links and screw them into the threaded pump holes on each side at 9:00 and 3:00 clock position and jerk on the chain until the pump slides out up scope wrench
Crude and it works boogie grin
Posted By: crackedback

Re: DIY 727 build questions - 07/22/22 10:05 PM

Take all bolts out of the pump, put in longer bolts that allow for some space, pump to drop, stand on bellhousing and hit tailshaft with a mallet. Pump drops out, no slide hammer needed.

The 727 rebuild video is a great reference as well.

https://youtu.be/nmYAL7i32fA

There are some on youtube by a guy in australia, very good
Posted By: Tig

Re: DIY 727 build questions - 07/23/22 11:36 AM

I've been doing mine for years, ever since I lost gears at the track and a racer helped me fix it whilst there. We got away with just band adjustments at the time but I bought a few books, trawled the 'net and re-built my first one soon after. I made a slide "hammer" to pull the pump housing and a couple of spring compressors for the drums. I had various bits of pipe turned down to use as bearing drifts. I don't have a stand, they go on the bench supported by wooden V blocks, but this makes fitting the drums onto the o/p shaft awkward, easier to do this vertically. I'll get round to sorting something for that one day but so far I've managed.
My approach to rebuilding is modular, I just do the pieces that come out in one lump, ( V/B, pump, front drum, case, etc). Do them one at a time, clean, check, measure, repair and replace (if needed), then set aside ready for refit. Use a good auto box assembly grease and a lip seal installer, take your time, soak the bands and clutches, measure everything and write it down. Air check. So far I've done OK, I did burn up a front clutch pack a couple of seasons after a rebuild but I didn't replace the front pack as they were still within spec (albeit on the loose side). Lesson learned wink . I have been asked to build 'box's for other's but it's not something I want to get into, I usually encourage them to do there own.
I usually refresh a box after 4 seasons but we don't race as much here, as you guys do over the water. 6 or 7 meetings a year if I don't bust stuff from wheelstands, which I have done for 4 years running now blush. I get my parts from various vendors, CRT, Marsh performance, A&A etc. H/D Bands and racing clutches (Alto Kolene) are readily available over here, or they at least used to be. I have a good selection of spares.
HTH's up
Posted By: Brad_Haak

Re: DIY 727 build questions - 07/23/22 01:14 PM

All good feedback; highly appreciated wrench
Posted By: Moparite

Re: DIY 727 build questions - 07/23/22 02:14 PM

Another issue that is often ignored is the sprag or over running clutch. If it lets loose you could crack the case and you will be building another transmission(ask me how i know this). It's good insurance to get a bolt in sprag this will keep it from spinning and possibly cracking the case. Some also are built stronger than the stock ones and can handle more.

https://www.coperacingtrans.com/?product=crt-727-16-roller-drag-sprag
Posted By: justinp61

Re: DIY 727 build questions - 07/23/22 03:47 PM

Originally Posted by AndyF
I checked over the 727 in my Duster before the season and it only took a couple of hours to pull valve body, pull the pump, open it up and take a look. Everything looked good so I put it back together and checked the end play. Piece of cake once you have a few tools and know the drill.


Andy, why such low resolution on the indicator? LOL.
Posted By: Cab_Burge

Re: DIY 727 build questions - 07/23/22 05:22 PM

Originally Posted by Moparite
Another issue that is often ignored is the sprag or over running clutch. If it lets loose you could crack the case and you will be building another transmission(ask me how i know this). It's good insurance to get a bolt in sprag this will keep it from spinning and possibly cracking the case. Some also are built stronger than the stock ones and can handle more.

https://www.coperacingtrans.com/?product=crt-727-16-roller-drag-sprag

isn't that Sprague a stock Ford?
I seem to recall that being stated on here years ago: work: Sorry for not remembering the exact application, C6,C4 or ???
Posted By: 451Mopar

Re: DIY 727 build questions - 07/23/22 06:16 PM

alternative to slide hammer for pump removal. Long bolts with large body washers, than use the "V" part of a large crow bar to slide along the length of the bolt like a slide hammer.
The trick to the front drum compressor is to have a flat surface under the drum. Two large "C" clamps can then be used to compress the spring retainer plate (just do it evenly.) A setup like shown with all thread in the center makes the job easier because it compresses/releases both sides at the same time.
Snap ring pliers, small flat blade screw driver for the servo and clutch snap rings, #2 phillips screw driver for valve body, Tail shaft phillips screws are easier to remove with an impact screw driver. Normal sockets and wrenches, mostly 7/16", 1/2", 9/16" sockets and larger wrenches for the band adjustment lock nuts.
If replacing bushings, a bushing driver kit. Usually at least replace the pump bushing and output shaft bushings.
Trans-Go TF-2 shift kit if doing a shift kit.
Under 500 HP, a regular Trans-Star trans rebuilt kit (tan clutches, untreated steels) should work fine. For higher performance, The Alto red eagle clutchs and kolene treated steel are normally used. There is also some in-between cost/performance options like the Green High Energy clutches.
There are different materials for the front band, I really couldn't tell all that much difference?, but I don't do alot of transmissions.
A 3.8:1 or 4.2:1 front band lever seems to work best.
An old paint can makes a nice support for the front pump, input shaft, and clutch assemblies then you can air test the clutch assemblies and measure clutch play with a dial indicator.
The large "C" clamp can also be used to hold the servos in place when removing / installing the snap rings, but a large vice grip welding "C" clamp is easier to use.
https://www.lowes.com/pd/IRWIN-VISE..._gIaoN-2kQaAvIAEALw_wcB&gclsrc=aw.ds
Posted By: Moparite

Re: DIY 727 build questions - 07/24/22 11:04 AM

Quote
isn't that Sprague a stock Ford?

Not sure what you are referring to, The link is for "NEW FOR 727 TRANSMISSIONS".
Posted By: moparx

Re: DIY 727 build questions - 07/24/22 04:48 PM


isn't that Sprague a stock Ford?
I seem to recall that being stated on here years ago: work: Sorry for not remembering the exact application, C6,C4 or ???"



Cab, i remember reading in a magazine long ago about using a C6 sprag. i can't remember what magazine it was, but i'm sure it mentioned a C6, and it was used because it had more springs and rollers in it.
i wished that could be confirmed, or discovered i am full of bullpucky.
beer
Posted By: an8sec70cuda

Re: DIY 727 build questions - 07/25/22 01:45 PM

I don't have a trans fixture to hold it on an engine stand, but I do have a pair of chains and a roof truss. laugh2
It worked perfectly to drop in the clutch drums and front pump. Everything else can be done easily on a workbench. The weight of the drums makes it more difficult sideways.

Attached picture trans chains.jpg
Posted By: 440Jim

Re: DIY 727 build questions - 07/25/22 02:12 PM

Originally Posted by Brad_Haak

3. Do you have any preferred suppliers for these tools and/or standard & performance parts for the job?

I couldn't resist buying another tool. But it wasn't expensive and is different than I already have.

Amazon WINtool clutch spring compressor
I took some pictures from the one I bought. I would slide the jaws to about 4" ID for a TF727 front clutch (Tool max ~4.3")

Attached picture Clutch_spring_Compressor-WINtool4.3a.jpg
Attached picture Clutch_spring_Compressor-WINtool727.jpg
Attached picture Clutch_spring_Compressor-WINtool.jpg
Posted By: crackedback

Re: DIY 727 build questions - 07/25/22 03:59 PM

WV Bob's trans stand was best, Wheelbarrow

Awesome.
Posted By: Brad_Haak

Re: DIY 727 build questions - 08/05/22 01:18 PM

FYI, I just received a copy of the 727/904 book by Tom Hand and it looks like it's also a good reference for DIY work ==> LINK HERE

Still waiting for the spring compressor like 440Jim showed above to arrive...
Posted By: JohnRR

Re: DIY 727 build questions - 08/08/22 02:57 PM

Originally Posted by Brad_Haak
FYI, I just received a copy of the 727/904 book by Tom Hand and it looks like it's also a good reference for DIY work ==> LINK HERE

Still waiting for the spring compressor like 440Jim showed above to arrive...


I have the factory chrysler compressor ... which does double duty for pressing in the outer race of a rear sprag .... but in a pinch when rebuilding a power glide I made something out of a PVC pipe coupling that I was able to compress with a big C clamp we had at work.

That one that Jim shows would come in handy for many different types setups like that .
Posted By: Cab_Burge

Re: DIY 727 build questions - 08/08/22 06:38 PM

Buy yourself a 1965 to 1971 Mopar Factory service manual, the tranny section is invaluable scope: twocents
Posted By: moparx

Re: DIY 727 build questions - 08/11/22 04:47 PM

an ATSG [Automatic Transmission Service Group] book is also a good guide for the do-it-yourselfer.
beer
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