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PACT 727 to 518 Conversion Kit

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mattimuss

Number of posts: 148
Location: El Cajon, Ca
Age: 49
Registration date: 2009-05-04

PACT 727 to 518 Conversion Kit

Post by mattimuss on Mon Aug 15, 2011 8:21 pm

Hello All!

I am getting ready to pull the engine and trans from the van. I was browsing the Internet searching for any info on an overdrive transmission conversion and found a company that claims they can convert a 727 to a 518 with a simple kit.

The company's name is PACT. Has anyone heard of them or used this kit?

w w w [dot] transmissioncenter [dot] net/727transmission [dot] htm

If not, has anyone here done an overdrive transmission swap?

MoparFreak69

Number of posts: 216
Location: Boise, Idaho
Age: 33
Registration date: 2011-07-01

Re: PACT 727 to 518 Conversion Kit

Post by MoparFreak69 on Mon Aug 15, 2011 8:45 pm

If you get a late 80's, very early 90's overdrive transmission (A518) from a van or 2wd pickup they are very simple to hook the OD up on. Just a 2 wire plug, ground one side and power the other. Everything else is basically the same as a standard 727 as that is what they are based off of. They remained the same until well into the 2000's until they dropped the 4 speeds in favor of 5 speeds.
The 518 I mentioned does not have a lockup torque converter however. These didnt come until the later 518/618 transmissions that had computer controlled lockup and od functions.


Just looked at the site. What it looks like they are doing is just installing 2 pressure switches into the transmission to operate OD and torque converter lock up on later 518/618 transmissions. This is probably ok, but I would personally install a seperate switch to allow me to manually shift it out of OD in certain times of need (same reason factory installed an OD off switch on the dash/shifter).
The description is a bit misleading. What they dont tell you is that you have to have a 518 transmission to put these parts into. These parts only make the shifting/lockup automatic. Aside from being a bit longer a 518 will fit in place of a 727 behind any small block V8. They did not make a 518 in the big block pattern so if you are planning that route an adapter will be necessary (although I have heard rumors that the V10 and Cummins bell housings are the same as the old big blocks??? / unconfirmed by me though).

mattimuss

Number of posts: 148
Location: El Cajon, Ca
Age: 49
Registration date: 2009-05-04

Re: PACT 727 to 518 Conversion Kit

Post by mattimuss on Tue Aug 16, 2011 8:50 am

Thanks for the reply and info.

Bear with me and my 'dumb' questions.

Would I have to fab a new trans cradle for the A518 or can you use the tail section from the 727 hooked to the A518 and use the original hanger mount?

Will the drive shaft need to be modified?

Thanks...


MoparFreak69

Number of posts: 216
Location: Boise, Idaho
Age: 33
Registration date: 2011-07-01

Re: PACT 727 to 518 Conversion Kit

Post by MoparFreak69 on Tue Aug 16, 2011 10:08 am

No problemo.
The tail section of a 518 IS the OD assembly. The front of a 518/618/46re/etc is basically exactly the same as the 3 speed 727. You would have to use the 518's tail housing in order to have OD.
As far as I am aware all 2wd 518s are the same length so you will definately be looking at driveline modification. Im not sure if your van has a ball and trunion assembly or the later slip yoke, which is what the 518 will have. Any competent driveline shop can modify your shaft or build you a new one for under $200. If your transmission has a slip yoke I bet shortening would run under $100 if the shop is honest.
As far as trans mount/cradle, yes you would need to basically fabricate your own mount, or get the mount setup from a B-van (70's-on) and mount it up to your rig, with modifications of course. No 518 has the top mount like the A-series vans had so this is your only option. Its quite easy if you have some mechanical/fab skills otherwise it may seem like a daunting task.

To add a bit more to your first question, yes that kit will make installation of an OD trans into your Van easier/nicer. It will eliminate the need for you to have to wire up your own system and go through the trial and error problems associated with it. As I mentioned you wont have an option to not use OD unless a switch is added but that is only a minor inconvenience, even less if you live in flat land area and dont tow/haul much.

RodStRace

Number of posts: 2863
Location: Chino Valley
Registration date: 2010-01-21

Re: PACT 727 to 518 Conversion Kit

Post by RodStRace on Tue Aug 16, 2011 10:29 am

I see you have a 108, which is the ONLY wy I's consider it. The 518 is the same externally as a 727 until you get to the tail section. That tail section is longer (big problem in a 100) and fatter. They require cutting and welding to fit in muscle cars, due to the fatter tail. It interferes with the torsion bar crossmember. Since the vans have the trans hanging down, there will be little to no issues.
1993-94 is when the lockup torque converter was added.
You can decide if you want the added MPG and slightly lower RPMS on the freeway (approx 100 RPM) with a stock stall speed which is best for a stock or mild build, or go with an earlier non-lockup trans and be able to use any aftermarket torque converter with higher stall speeds and more strength. That would be more suited to a more radical build, along the lines of a street/strip car.
The weak link is when the trans is in OD and you hit the throttle, the 3rd gear clutch pack ends up between a rock (the tall gearing) and a hard place (engine torque). It is best to use a throttle switch or vacuum input to kick it out of OD. If you run a Torque Converter Clutch (TCC) for lockup, it is nice to have a switch for that too. Most use a brake switch input for this, just like a cruise control.

MoparFreak69

Number of posts: 216
Location: Boise, Idaho
Age: 33
Registration date: 2011-07-01

Re: PACT 727 to 518 Conversion Kit

Post by MoparFreak69 on Tue Aug 16, 2011 4:40 pm

I dunno about skipping its use in a 108. I did a little rough measuring and the 3 speed thats in my pickup is roughly a foot shorter than a 46RE that I have in a pickup (just a very rough estimate because the 46RE is 4wd). Taking a foot out of my driveline still leaves me with a longer driveline than the one in my Wrangler, and it flexes a whole ton more than the A100 is ever going to think about. Another thing is that my truck has a slant 6. This means the engine is quite a bit longer than a V8 that will eventually find its way in that spot. Figure at least 6" that I can move the motor forward and that gives the driveline more breathing room.

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