Chuck the Truck's 52 Chevy - 700R4 Installation & Payback Calculator

700R4 Installation

Traffic is getting heavier, and I drive it all the time, even on business. It only takes a couple trips stuck in rush-hour stop-and-go to get really tired of the clutch. The 833 overdrive is a good trans but it's time for a change. With an auto, the missus can drive it too (you know where that leads - something new for me!) I'm waiting on parts, but I'll document this swap as best I can. I'm hoping to defray some of the cost by listing the 89mm trans and all the goodies for sale on Ebay, unless someone reading this saves me the hassle. 03/02/05

The cooler can go in before I take the truck down. It is a B&M 70264. It fits well in front of the electric fan, using the support rods as a mount. I only needed hardware that was included in the kit to install it, except for two cable ties at the bottom. You can see the clearance as well as the uncinched ties peeking out. 03/05/05

A bit of black paint so it is invisible once it's all back together. The 5/16" tube came from my friends at Master Auto in Frankfort, my favorite local parts store. I cut and bent it to fit, putting the flare junction on the engine side of the horse collar. Since it is relatively inaccessible, I used my flare kit to put a bump on the end if the tube at the cooler. The pressures aren't that high, but I don't want them popping off while I'm on my way to fish.

If I was more inclined to work, I'd have pulled the horse collar and run the tubes down low. The high routing was easier, so there.

Hardest part of the trans install? The carb. Say what? The TV cable has the large molded adjuster mechanism that ran so close to the valve cover on my 250 with a sideways 4 barrel that there was no room for the cable bend. I considered two 2" carb spacers, turning the carb around, and a bellcrank to remote mount the TV cable. The bellcrank won and the TV doesn't know it isn't mounted to the carb. This pic shows the new throttle cable with my homemade bracket fabricated to allow just enough bend radius for smooth operation.

I bought lots of hardware that didn't work and wound up making my own. The Lokar bracket on the left put the cable too low, too close the carb linkage, and too far back. The cable was skewed as it ran to the carb linkage. Other than that it was perfect. I made one so the cable has a straight shot to the linkage and gives the clearance from valve cover needed.

Input - Left
TV - Center
Carb - Right

I contemplated mounting the bellcrank to the block, but the proximity of the plastic coated TV cable to the headers didn't give me any warm fuzzies to longevity of the cable. I decided on a frame mount. Reading and a bit of trigonometry laid out the bell crank. The TV link must be 1.109 +/- .016 center to center, and travel through a 78 degree arc. I measured the carb travel from closed to open and throttle pedal travel coming off my previously fabricated firewall mounted pivot. Since everything on the bellcrank must travel the same 78 degrees, it was basic trig to get the other link lengths. The cable end of the link ciphered out to 1.341 c-c, a number that jived with a purchased but unused TV Cable Corrector link for the Edelbrock carb (2.45" from TV to throttle cable). My input link had wider range possible, from 3/4" to 2" but I set it at 1". I made the links a light press fit on a 2" section of 1/2" black pipe. Two 3/8" ID x 1/2" OD bronze flange bushings riding on a Grade 8 3/8" bolt complete the pivot. Once I trial fitted and had the links at the proper angles, I tack welded them in place. 04/14/05

A hundred holes in the frame and none in the right spot, so I drilled a new one. If I hadn't been trying to keep the vehicle drivable prior to the actual swap, I could have used the pivot I installed for the clutch linkage. The bracket is for the lower end of the throttle cable, the nut is the pivot.

The throttle cable bracket just has a couple 90 degree bends in it, with a tab welded inboard to keep it from swiveling.

I'll flip the pull rod from the pedal so the link is more vertical once the clutch linkage is gone. Everything clears and it all works great. The TV will be tucked inside the frame rail, protected from splash by the boxing plate and I'll fab a shroud if needed.

Old stuff coming out.

Pilot removal made easy. A 9/16 bolt, lightly ground to fit the bushing, and wet toilet paper. Sounds odd, but works great. I was a "greaser", using wheel bearing grease, until I tried this. Just as quick and whole lot cleaner.

Flexplate from Summit. I paid for the cheap, non-SFI flexplate, but it has the SFI sticker. I'm not racing, but I consider that indicitive of a quality level. Of course the sticker was over the hole I needed.

Installed with a set of ARP bolts.

The 2200 RPM stall converter is stock diameter. Sometimes seating a converter can be a trick, but this clicked right in on the first try. (My nephew had one that took three hours of futzing. Don't try installing the trans if it's not home). The rebuilt trans and converter came from a local shop, Tony's Transmissions in New Lenox, IL, for less than an Ebay trans. If I do have trouble, they're only a few blocks away, which beats dealing with a shop halfway across the country.

01/08 25,000 miles and nary a leak nor a lick of trouble. I should stop back and say thanks.

The Lokar shifter is ala carte, so the module, indicator, boot, and relays are all separate line items. It does add up ($$). Here is the shifter bracket mounted to the trans, and the PRNDL module on the side.

Up and in with no difficulty. The trans x-member had to move back an inch,

while the driveshaft was 3" shorter.

The PRNDL module with linkage installed.

Eyeballed the install then bent the cooler lines by hand. Tape measure? We don't need no stinkin' tape measure! I tied the lines to the block and put the flex coupler up by the rad. If I had tied them to the frame, then the flex hoses would be close to the exhaust pipe, not good for longevity.

Lots of holes now. Time for a new trans cover?

Patched. Isn't this the way Troy Trepanier would do it? Heck it'll do for now.

Mounting the shifter took way longer than it should have. The bolts didn't want to start, but after a lot of encouraging words, they went in. It is a 16" stick, and I mounted it all the way forward to clear the seat in L1. Not that I ever need it, but just in case.

The universal dipstick fit fine after a tweek with the conduit bender.

I made a bracket for the PRNDL indicator and mounted it under the dash. From the seat it is unobtrusive, but I can see it if need be.

I bought a Painless Performance Lockup kit to control the converter. It includes a 4th gear pressure switch for the trans, lockup solenoid, brake switch, and a vacuum switch. When I first put it on the road it was locking up way too soon. I checked and the vacuum switch was engaging at 4" and disengaging at 2". Heck, by the time I'm that low, it has kicked down to 2nd or 1st. I tried the vacuum delay valve they recommended, to no avail. There was no adjustment on the switch, so I found an Air Logic adjustable vaccum switch, V-5100-28-xxxx, at PneuAire.

(Oh to heck with the vacuum switch - see below)
It adjusts from 3" to 28", so I kept stepping it by trial and error. I'm now engaging at 13" and disengaging at 9" (using the delay valve). It is shifting well for me now, almost like a 5 speed trans. 4th unlocked engages while I'm still accelerating, then when I hit cruise speed, the converter locks feeling almost like a 5th gear. On moderate hills or light acceleration, the converter unlocks but I stay in 4th, rather than kicking down. I'm pleased with the performance. You can keep the romance of stick shift - automatic is sweet.

Payback Calculator

Thinking about an overdrive trans swap to save on gasoline? Or any swap or purchase justified strictly by a gas mileage improvement? How long will it take to break even? I ciphered out a formula.
Let C = Cost of the conversion/purchase in dollars (be realistic)
G = Price of gas per gallon in dollars
P = Present Miles Per Gallon
N = New Miles per Gallon
M = Miles driven to break even
M=C/[G*(1/P - 1/N)]
For instance, if I spend $1000 (C) to boost my mileage from 17MPG(P) to 20MPG(N) and gas is $4.25 per gallon (G)
1000/[4.25*(1/17-1/20)] = 26667 miles to payback
but if I went from a paltry 9MPG to 12MPG (same 3MPG difference)
1000/[4.25*(1/9-1/12)] = 8471 miles to payback
Too much like math? I put the formula into an Excel spreadsheet so you can just plug in the numbers. Download (right-click, Save Target As...) the following file, payback.xls

Ok, I'll bet you thought I'd get around to the cover like I'd get around to finishing the door strike properly.  Hah!  I got the new cover and quickly realized that welding in the original was stupid.  I got it cut out, leaving enough to screw this one in.  Some hammer work reshaped the pan for bellhousing clearance.  The truck is a whole lot quieter without the floor touching the trans.  10/01/05

The leather boot was more dificult to install than the molded rubber ones.  I centered the flange first and predrilled pilot holes in the floor, then worked my way around the perimeter, tucking the boot under the flange and securing it with the screw.

The vacuum switch for converter lockup was still less than perfect.  If it had adjustable hysteresis, it would have been better.  I finally broke down and relegated lockup control to the onboard computer - me!  A subminiature toggle switch tucks neatly into the turn signal switch housing.  It controls a relay that replaced the vacuum switch, so I still have the 4th gear pressure switch and brake switch in the circuit.  NOW it locks and unlocks exactly when I want it to.  I never have to take my hand off the wheel like with a dash mounted switch.  I easily reach it with a finger.

From time to time I was getting a vapor lock problem, so I fixed it good.  I used a Mallory return style regulator (#4309) and  plumbed in a return line.  The line is soldered in through the sender flange.  While I was at it, I opened up the tank outlet to 1/4" NPT and plumbed the whole system in 3/8" steel.  With a new Carter P4070 rotary vane pump, I'm bulletproof.  The only "stagnant" fuel in the 2" from the carb to the tee.  The fuel lines stay nice and cool.

I also plumbed a fresh air intake.  The air cleaner assembly is off a late 80's Chevy truck TBI, the duct from the missus clothes dryer, and spud in the fender is courtesy of Maxwell House.  The fender liner I installed makes that corner a good place for cool, dry, air.