Time to upgrade the 727

[Dualtire90]

I'm sure I am beating a very dead horse at this point but my trans is nearing the end of it's life and I am looking for some advice on what works and what doesn't. My truck is a 90 2WD single cab dually. As much as I would love to do a swap to a 47rh or swap in a manual, due to time, workspace and money considerations, that isn't going to happen this time around. The engine is mostly stock at this point aside from exhaust and some mild tweaking to the pump but I plan on bumping up the power later on so I want to build the trans with enough strength to allow for that. The truck is used as a daily driver most of the time and sees occasional towing but not much and so far, nothing heavier than a single car trailer. Once I have worked on the power side of the equation, I want to take it up the drag strip and play around with it.

Here is my rough plan thus far:
- rebuild the original 727
- lower stall torque converter, perhaps around 1300rpm
- upgraded flex plate
- a shift kit, something along the lines of what some might call a "towing" level kit or "stage 2" kit.

I have been toying with the idea of installing a GearVendors unit on it but I have heard mixed reviews on how well they handle power and how long they last versus what they cost. Any input from you guys would be greatly appreciated. I'm a heavy diesel mechanic by trade so I have a good understanding of how it all works, I'm just not familiar with these tranny's. Thanks again!

[cmann250]

Have you considered a 46RH swap from a later 1st gen? They're a pretty cost effective way to get over drive.

[Dualtire90]

I've thought about it but I haven't looked in to it very closely. How involved is the swap and how well do they hold up to power upgrades?

[cmann250]

The drive shaft is different and you'd have to wire up over drive. These Chrysler autos will hold about anything with good upgraded parts. Example: BC847's transmission

[Philip]

A rebuild kit for a 727 and 518 are almost the same price. The 727/518 use the same converter. Go with an OD trans. core 518's are cheap. You can be rebuilding it while the 727 is still moving you around.

Those 3:08's your running and a OD trans makes a nice package for road usage. Right now at 60 MPH your turning 2K RPM. With a OD you would be turning 1650 for the same speed. The truck would be a lot quitter.

[Dualtire90]

I would love to be seeing 2k @65. Right now, the trans or torque converter is slipping so badly I'm running 2550 rpm @65. Are there any shift linkage differences between the 518 and 727?

[cmann250]

No. Shift linkages are the same, as is the TV cable and cooler lines. If I recall correctly, I even used the 727 style mount when I put one in my '89. Over drive is controlled by a solenoid, so you need a pig tail (power and ground). I wired it to a dimmer switch on the floor. The drive shaft is a slip yoke instead of a fixed yoke on the 727.

[Sutter1stgen]

Longer front drive line and shorter rear. How much?I can't remember. I now use a dimmer switch to control O/D. I would t shoot for the grass on stall speed. A aftermarket converter from one of the big name companies will be more effiecient PERIOD. If you go with too low of a stall it will make your truck a pig off the line, towing or hauling will only worsen the event.
I run a Specrite and my boss's truck runs a "off the shelf" Suncoast converter. My flare stall is lower than is but our brake stalls are about he same. His truck runs larger tires and can get spooled up significantly faster than mine. I can cruise with a trailer at slightly cooler Trans temps because of a more effiecient feel in the lower rpm.
As for a shift kit, that's a must. I'd stick with a trango kit, they seem to really be dialed in for a diesel application. I'm running a Fairbanks transaction kit and I've finally got it about as tuned in as possible after 3 years. Lol
I just switched out my 3.07s for 3.54s. They make the shifts between gears feel more positive, and the engine is always in the meat of its torque/power. I want to say at 2k Rpms I was cruising at 82mph.

[txs]

You could even make the 727 a lockup, only thing is they never made a solenoid actuated 727, they are hydraulic controlled.