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Randy’s Transmissions is a US heavy-duty transmission specialist. At Willys Workshop we carry their built transmissions, valve bodies, converters and driveline parts for Cummins, Dodge/Ram and Duramax. Stocked across popular applications including the Duramax, 5.9L and 6.7L. Supplied and fitted at our Oxley (Brisbane) and Warana (Sunshine Coast) workshops, or shipped Australia-wide.
What Randy’s Transmissions is for
This is the range for American diesel automatics that are being asked to do more than they left the factory able to handle. Towing, tuning and added torque all put load through the transmission first, and it is usually the transmission that gives up before the engine does.
We stock complete built transmissions, plus the parts to build or service one yourself: valve bodies, torque converters, shafts, deep pans, service kits and coolers. Coverage is heaviest on Dodge and Ram Cummins, with strong Duramax and Ford Power Stroke support.
Which transmission do you have?
Get this right before anything else, because parts do not cross between families. The common ones here are the 68RFE and the older 47RE / 48RE behind Cummins, the Allison 1000 behind Duramax, and Ford’s 5R110W, 6R140 and 10R140. The Aisin AS68RC and AS69RC turn up in heavier Ram applications, and the 10L1000 in later GM.
If you are not certain which one is in your truck, tell us the year, model and engine and we will identify it. A valve body or shaft for the wrong family will not fit and is not a cheap mistake.
Build it or replace it?
A complete built transmission is the straightforward answer when the current one is already damaged or when you want a known specification with everything matched. It is the larger up-front cost and the smaller risk.
Going part by part makes sense when the transmission is healthy and you are getting ahead of a known weak point, most often the valve body, the input or output shaft, or heat. Which of those matters depends on what you tow and how hard the truck is tuned, so tell us both.
Heat is what kills them
Most towing-related transmission failures are heat failures. Fluid that runs too hot loses its film strength, and once that goes the clutches and bearings follow. A cooler kit and a deep pan together add fluid capacity and shed heat, and they are the cheapest insurance you can buy on a truck that tows.
If you are towing near capacity and have never fitted either, start there before you spend on internals. We can advise on the right combination for your setup and fit it in-workshop at Oxley or Warana.
Randy’s Transmissions FAQs
How do I know which transmission is in my truck?
Tell us the year, model and engine and we will identify it. As a rough guide: 47RE and 48RE behind earlier Cummins, 68RFE from 2007.5, Allison 1000 behind Duramax, and 5R110W, 6R140 or 10R140 behind Ford Power Stroke depending on year. Do not order parts on a guess, because nothing crosses between families.
Do I need a built transmission or just a valve body?
A valve body upgrade changes shift firmness and pressure and can meaningfully extend the life of a healthy transmission under tow. It will not save one that is already slipping or has debris through it. If yours is damaged, a complete built unit is the honest answer.
Will a transmission cooler actually make a difference?
On a towing truck, yes, and it is the highest-value thing on this page relative to what it costs. Heat is the usual cause of towing failures, and added cooling plus a deep pan directly reduces it. Fit both before spending on internals.
Are these parts for American vehicles only?
Mostly. The range is built around Dodge and Ram Cummins, Chevrolet and GMC Duramax, and Ford Power Stroke. If you have imported one of these trucks into Australia we can still supply and fit for it.
Can you fit and build in-house?
Yes. We supply Australia-wide, and we fit transmissions and coolers in our own workshops at Oxley in Brisbane and Warana on the Sunshine Coast. Larger builds are worth a conversation before you order.
How long does delivery take on a complete transmission?
Complete units are large freight items and lead times vary with what is in stock. Ask us before you commit, and we will give you a real timeframe rather than an optimistic one.
