The Ricardo transaxles came from the Ford GT program when Ford asked Ricardo (in the UK) to build a bespoke transaxle for their halo car of 2005-6, the Ford GT. The gearbox Ricardo produced -in record time- was the only modern transaxle (6 speeds, advanced triple-cone synchronizers, internal oil pump, very high input torque rating, etc) in recent memory that was designed for mid-engined use in very high torque V8 engines, at least at an affordable price point.
Ricardo did the transaxle work under extreme time pressure, and featured the transaxle in one of their quarterly publications, which is available here: FordGTCaseStudy.pdf
These transaxles can occasionally be sourced from eBay, typically from wrecked Ford GTs. For a while after they were first produced, some people reported that about 1 Ford GT per day was being wrecked, so the supply at that time was decent. However, most of the ones that remain are in the hands of owners that have had them for a while, and haven't wrecked them yet, so that rate of destruction is likely not to repeat itself. And because prices of the Ford GTs have remained high. more of the wrecked cars are being rebuilt, making the transaxle supply problem worse.
There was a source in Europe that was using NOS parts and transaxles from Ricardo, and rebuilding them; however that person has passed away, and there are no more units available from him.
The Ricardo transaxles have very limited availability, but are generally thought to be the best transaxle for high-powered cars. Ford supposedly has a very small number of new ones in stock- at a reputed price of $17000, plus a core.
Only a few shops are really capable of working on these semi-exotic transaxles, but many of them have passed through RPM Transmissions.
The transaxles have 6 forward speeds, triple synchros on most gears, have a torque-sensing limited slip, and an integrated oil pump and ports designed for an external oil cooler. The crownwheel is huge for a street transaxle, which is one reason why they are among the heaviest units, weighing in at around 200 lbs dry.
Several Ford GT owners have built their cars to over 1000 HP, and there are no reports (of which we are aware) of power-induced transaxle failures. These are probably the strongest transaxles available for the SLC.
A complete set of Ricardo drawings for this transaxle is available here: Ricardo Diagrams.pdf
Gear ratios are:
Final drive ratio is 3.36, but Stillen made a small run (<25?) of much shorter final drives which gave even greater acceleration. These are NLA, but used ones may be available. A good place to search is the Ford GT forum
The stock gear ratios are ideal for a street-driven car, as they were selected for a powerful, torquey V8, and yield a very high top speed combined with potentially good fuel economy due to the upper three gears being overdriven. Race gearing would be much shorter.
Another goal for the Ford GT was a low 0-60 MPH time, so it would get good magazine coverage. Thus, the car was geared so that 60 MPH could be achieved in first gear, saving a shift that would have added tenths to the published times.
The reverse switch for the Ricardo closes the circuit when reverse is selected. It uses a standard 2-wire weatherpack connector.
The Vehicle Speed Sensor (VSS) uses a pigtail from, supposedly, a T5 transmission. Standard Motor Products part # S699 is a pigtail that can be used.
Shifter and shift cables
The transaxle can be shifted with either the now-standard Brandwood shifter, or the original Ford GT shifter (including the difficult-to-find short shifter). The shifter cables are provided as part of the kit, but because the builder can route them in different ways, and mount the shifter in different places, the cable length can't always be known in advance. The norm is to mount the shifter where you want it, route temporary "cables" made from clothesline and find the nominal length from the shifter to the bracket on the transaxle. That is the length Superlite needs to order the correct cables.
The cables may seem too short when delivered, but this can be managed by using adapters and nuts to fine-tune the connection to the actual transaxle arms. Note that by adjusting the balls connectors on the transaxle arms, the effect of a "short shifter" can be obtained.
The shifter thread size is M12 X 1.75.
The clutch uses a standard Ford Mustang clutch alignment pilot tool. ONe can be obtained from OTC- their part number is 308-599, and it can be sourced from eBay or Amazon for under $20.
Because the transaxle is designed for a mid-engined application, no inversion or other changes are needed, unlike the typical Porsche 911-based transaxles.
Early Ford GTs had a batch of defective axle bolts, which tended to break due to an incorrect heat treatment from a supplier. Most of the existing transaxles have had the correction, but all of these transaxles should be inspected to be sure that the upgraded axles bolts (and washers) have been installed. If you can't be sure, replace them with the Ford kit, or the ARP-sourced kit from Accufab. Repair parts are non-existent from Ford or Ricardo, with a few people holding some damaged transaxles in inventory for use as parts.
Here is a picture of a Ricardo transaxle with the defective axle bolts installed. One bolt has already started to back out here...
And another in which one of the bolts has already lost it's head...
A failure of these bolts under load at speed could be deadly. Be sure you have upgraded these on your transaxle.
To tell if you have the right bolts and washer installed, read the following PDF here: axlebolts.pdf This PDF also has the correct torque specs.
The axles from Superlite use the popular and very strong 930 CV joints. These have a different size bolt circle than the transmission bells and so adapters are a standard part of the axle package. The bolts on these adapters must be torqued to 57 ft lbs per The Driveshaft Shop, providers of the axles.
When interfacing the LS engine to the Ricardo, a custom flywheel is usually used. This can be supplied by Superlite. The flywheels have a machined hole that is designed to insert a bushing or bearing, replacing the normal pilot bearing in the crankshaft with a conventional setup.
Some cars were provided with a brass bushing, and later cars may have come with a brass bushing with an integral roller bearing as shown here:
Another option is to use a traditional pilot bearing. There are a couple of options for such bearings. Grainger sells a bearing with part number 1ZGH3, which is a China-sourced bearing for less than $7. Another source is a bearing from Lakewood, which is made domestically, and carries part number 15975. This bearing is available from Speedway and others. The inner diameter for the input shaft is correct, but the flywheel will have to be machined to fit the outside diameter of either of these two bearings, both of which carry identical dimensions. The Lakewood bearing is typically around $30, but appears to be of higher quality.
In addition to their high cost and very limited availability, these transaxles require a specific Ford GT starter (around $650) and the factory dual-disc clutch (about $1900). RCR/Superlite sells a custom adapter place to mate up the popular LS-series engines with the transaxle.
The clutch slave cylinder is internal to the case, and has a metric fitting. The proper m10 X1.0 to -3AN fitting can be obtained at Pegasus and other stores. This fitting allows a regular -3 AN line to be attached to the slave cylinder directly, and replaces the original line with the foil covering.
When mounting the Ricardo to the adapter plate you will need 2 alignment pins (f5rz-6397-c dowells @ $4.16 ea) available through Ford. There are nine clutch bolts (-n806178-s437 bolts @ $3.00ea) and you will use 6 Qts 75W-90 synthetic lube (xt-75w90-qgt oil @ $35.50ea).
Notwithstanding the text in the picture, these are not now readily available...
Here is a picture of an engine with a clutch for the Ricardo attached:
Note the use of a Ford clutch alignment tool, which is necessary to align the clutch pack so that the assembly slides onto the transaxle input shaft. Also note the adapter plate to mate the engine to the transaxle.
The electrical connections for the Ford GT40 starter are shown. The D-shaped single spade pigtail part number has not been identified as yet.
This is the T56 Reverse Light Weatherpak connector.
This is the S699 Speed Sensor Connector