Ready to Pull

We recently finished the last step in prepping our "classic" 7.3L F-350 for full-time pulling our Big Country. Brian's Truck Shop in Arkansas has, for years, specialized in rebuilding the Ford 4R100 heavy duty truck transmissions. Brian has several parts made special for him to replace parts that typically fail in these transmissions. You can either send him your transmission, have him rebuild it and send it back to you, or you can sign up to bring your truck in and have the transmission dropped, rebuilt and reinstalled all in one day. We chose the latter route.

The walls of the waiting room and the hallway nearby are covered with magazine articles mentioning his transmissions used in a variety of racing and pulling trucks around the country. Interestingly, he can also set up a 4R100 transmission to hook up to newer 6.0 and 6.4 engines, replacing the 5R100 transmission supplied with those trucks.

Brian's transmissions are built to withstand the forces of engines hopped up to 1000 horsepower levels and the shift strategies are fine-tuned to the purpose for which you plan on using the truck. In our case, it was for constant towing of a heavy fifth wheel trailer. Brian's tuning added 60 HP as well as optimized shift strategies for pulling the trailer at highway speeds. Most importantly, when downshifting from OD to D going uphill, the transmission immediately drops back into torque converter lockup. Stock transmission tuning drops out of lockup, increasing heat in the transmission. Brian also scrapped the stock 7.3L transmission cooler and replaced it with a much larger (about 3x larger) cooler used in the 6.0L trucks.

We're super happy with the way the truck pulls now. The extra 60HP made a noticeable difference pulling out of the hills of north Arkansas (where Brian's shop is located). Traveling on more level interstate, the truck stays in OD more than it used to for gentle rolling hills. The best part is that the unwritten warranty is essentially lifetime, though the official warranty is two years, unlimited mileage. Our cost out the door was $5,800. Having a rebuilt Ford HD transmission put into the truck would have been in the $4,500 range.

Did the extra 60 HP come from the work on the transmission or was that from chipping the engine or something? I have thought about chipping ours but when I figure the fuel savings from the chip compared to how long it would take to repay the work done I have stayed with the stock. I did install gauges so that I can keep an eye on the trans temp and the exhaust temp plus vacuum boost. Mine seems to run with plenty of all to spare but I do notice the difference in the fuel I buy, some gets more power and better mileage than the rest. I run cetane boost in mine nearly all of the time and it just seems to me that the government should be regulating fuel standards as much as they regulate fuel economy expectations from vehicles. It isn't very hard to tell the difference between a good tank full of fuel and when you get some that causes the truck to lug going up the hills and the fuel needle to drop like a rock. Tom

Actually, I should update the post. I ended up having to pull the 60HP chip, so I'm back to stock. Yes, the extra power came from a chip and not from the tranny. When pulling as heavy as we are, it is generally recommended not to chip more than about 40HP, if that, with otherwise stock components. Given all that, and my current lack of gauges (that's coming next), I didn't feel comfortable keeping the 60 in there.

I have been towing heavy going on 6 years with my hypertech unit with a gain of 80hp and never observe any alarming number. I call it protecting my engine with much better performance. Besides the BC hardly loads it up. With 40 to 60% load and peaks at 90% compared to 100% most the time stock.
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