# Mendeola transaxle (MD4/MD5, S4/S5, S4D/S5D, SDR)

- Source: https://racingcarnetwork.com/wiki/mendeola-transaxle/
- Publisher: Racing Car Network (racingcarnetwork.com), the race car marketplace
- Type: gearbox · Brand: Mendeola
- Discipline: parts, rally-offroad
- Series: rally-raid
- Era: 1990s
- Last updated: 2026-11-06
- For sale on RCN: https://racingcarnetwork.com/for-sale/mendeola-transaxle/ (7 live listings right now)

Mendeola transaxles are heavy-duty rear-mounted gearboxes from San Diego, built for sand cars, desert buggies, pre-runners and a few mid-engine kit cars. The MD range is a synchro four or five speed; the S4/S5 and S4D/S5D are ratchet sequentials. Weddle Industries has built the main lines since 2013, so parts remain available.

## Specifications

| Spec | Value |
|---|---|
| Type | Transaxle with spiral-bevel ring and pinion; MD series synchro H-pattern, S4/S5/S4D/S5D ratchet sequential [1][5][6] |
| Gears | 4 forward (MD4-2D, S4, S4D) or 5 forward (MD5, S5, S5D), plus full-size reverse on S-series [1][4][6] |
| Torque Rating | Not published by Weddle; the 2012 SDR5 street unit was quoted at 650 hp and 600 lb-ft; Rancho services units behind engines up to 1,500 hp [8][14] |
| Ring And Pinion | 10-inch Weddle Klingelnberg spiral bevel on MD and S4/S5; 11.5-inch on S4D/S5D [2][4][5] |
| Ratios | R&P 3.88 to 5.86 (MD), 3.56 to 5.14 (S4/S5), 4.63 or 4.88 (S4D); 1st gear 2.90 to 3.27 [2][4][5][6] |
| Weight | Shipping weight 126 lb (MD4-2D), 180 lb (S4), 190 lb (S5), 200 lb (S4D) [2][3][4][5] |
| Input Shaft | 300M steel; 1 in x 23 spline G50 type (MD4-2D), 1-3/16 in x 18 (S4/S5), GM 1-1/8 in x 26 (S4D) [2][4][5] |
| Case | A356 aluminium housings, T6 heat treated, shot blasted, billet side covers, bronze load bolt [2][5] |
| Applications | Long-travel sand cars, desert pre-runners, Class 10 and unlimited buggies, drag buggies, Factory Five GTM and Superlite SLC street kits [1][6][14][17] |
| Years | MD program from 1996; S4/S5 taken over and revamped by Weddle in 2013; SDR5 street unit from November 2011 [0][1][15] |
| New Price | USD 10,995 (MD4-2D) to 18,495 (S4D), Weddle and Rancho list prices, 2025 [2][4][5][6] |

## History

Mike Mendeola's company in San Diego grew out of the Southern California sand-rail scene, where VW-based transaxles were the limit on power. The MD program started in 1996 as a reworked VW Type 1 design with a 10-inch ring and pinion and larger differential gears. Weddle Industries of Goleta cut the gear sets for it from the start [0]. The early MD4E kept the Type 1 layout; one Samba poster calls it a Type 1 case on steroids [18]. The later MD4-2D moved to a G50-style 300M input shaft. It became the volume seller for LS-powered long-travel sand cars [5][6].

The S4 and S5 were a clean-sheet step up: 85 mm shaft centres, wider gears, bigger bearings, a usable reverse and a ratchet sequential shift. Weddle took over manufacture of the MD, S4/S5 and S4D/S5D lines in 2013. It revised the castings, shift mechanism, oil flow and mainshaft bearing retainer [0][1]. Rancho Performance Transaxles in Fullerton is the biggest Mendeola service centre. It dates the purchase of the rights to 2012 and says the units were gradually rebranded as Weddle [7]. The S4D and S5D keep the same gear stacks under an 11.5-inch ring and pinion. They come with an LS bellhousing for bigger cars and bigger power [4][6].

In 2011 Mendeola moved into street kit cars. Factory Five took deposits for a GTM transaxle in late 2010. The first production units shipped on 17 November 2011, about a year late [15]. The SDR5 was quoted at 650 hp and 600 lb-ft. In February 2012 it cost USD 10,950 bare, with a USD 2,400 master shift kit on top [14]. Early SLC builders noted it needed a specific starter and that real-world data was thin [17].

Mendeola Transaxles still builds the SDR line in small numbers. A May 2025 Factory Five forum thread records waits of two to three and a half years for SDR5 units. The same thread relays a remark from Mike Mendeola that he expects to build for only a few more years [16]. For the off-road MD and S-series, Weddle and Rancho are the practical suppliers today [1][8].

## Palmarès

A component rather than a results machine. Weddle's S4/S5 page shows Ron Weddle with a MORE PCI Class 10 winner from 2021 [1]. Rancho lists Mendeola units for engine outputs up to 1,500 hp, which covers Class 1 and sand-drag use [8]. SCORE Class 1 is an unlimited open-wheel class with normally aspirated engines of 500 hp or more on 37-inch tyres, the natural home of the S4D/S5D [26].

## What to check before you buy

Identify the exact model and who built it: MD4E, MD4-2D, MD5, S4/S5 and S4D/S5D share seals and load bolts but not inputs, cases or value. Weddle-built units (post-2013) have the revised castings and shift mechanism. Ask for the Weddle pick sheet or Rancho invoice. Ring and pinion ratio and gear set: Ratios range from 3.88 to 5.86 and a change means a full rebuild. Match the R&P to your tyre size and engine before you pay; sellers on RCN usually list R&P and 1st to 5th. Which engine it sat behind, and the bellhousing fitted: VW top-starter, VW side-starter and Chevy bellhousings are different parts. An S4D comes with an LS bellhousing for an 8-inch triple or 9-inch twin disc clutch; the MD4-2D does not. Drive flanges: 930 or 934: 930 is standard on the MD4-2D, 934 is a USD 279 option and standard on S-series. Your axles and CVs must match. Date and content of the last rebuild: Used listings in 2025 and 2026 lean on a fresh Rancho or Weddle rebuild as the main selling point. Ask whether the heavy-duty front bearing, bronze load bolt and new seals went in. Look for oil at the input seal and the final-drive seals: Seal leaks are the most common fault reported by owners, and a weeping input seal can mean a damaged seal bore rather than a bad seal. External oil system and cooler fittings: S-series cases are pre-drilled for an external oil system. High-power desert cars run a pump and cooler; check the ports are plugged or plumbed, not stripped. Shifter, cables and gear display for sequential units: A Harget dual-lever shifter and dash display are extra-cost items. A used S-series without them costs several hundred dollars more to put on the road.

## Did you know

- The MD program began in 1996 and Weddle cut the gears for it from day one, long before taking over the whole transaxle in 2013 [0].
- The first production Factory Five GTM transaxles left Mendeola on 17 November 2011, roughly a year after deposits were taken, at two or three units a week [15].
- S-series cases are about two inches narrower than a VW Bus transaxle despite carrying an 85 mm shaft centre distance and a 10-inch ring and pinion [2].

## Frequently asked questions

**Is a Mendeola the same thing as a Weddle S4 or MD4-2D?** Largely yes. Weddle Industries has made the MD, S4/S5 and S4D/S5D since 2013 and sells them under its own name. Castings, shift mechanism and oiling were revised. The street SDR line is still built by Mendeola Transaxles itself. Parts cross over between the two names.

**Which model do I need for an LS sand car?** Rancho sells the MD4S-2D as the usual choice for long-travel LS sand cars, at USD 10,995 new. Big-horsepower cars and desert buggies move up to the S4 or S5 sequential. Very heavy cars with big tyres and torque go to the S4D or S5D with the 11.5-inch ring and pinion.

**How much power will it take?** Weddle does not publish a torque rating for the off-road units. Mendeola quoted 650 hp and 600 lb-ft for the SDR5 street box in 2012, and Rancho services Mendeola units behind engines up to 1,500 hp. Forum figures of 700 hp for a 10-inch S4/S5 and 1,000 hp for the 11.5-inch S4D could not be confirmed.

**What should I ask a private seller?** Model and builder, R&P and 1st to 5th ratios, and which engine and bellhousing it was behind. Then 930 or 934 flanges, the date and content of the last rebuild, and whether the heavy-duty front bearing and load bolt went in. Ask for the Weddle pick sheet or the Rancho invoice.

**Who rebuilds them and what does it cost?** Rancho Performance Transaxles in Fullerton calls itself the world's largest Mendeola builder. It quotes by phone. Weddle stocks the internals. Seals, bearings and load bolts are USD 18 to 44 each; a new ring and pinion or gear set is where the money goes.

**Can I buy a new Mendeola-branded unit?** Only the SDR street line, and only with patience. Factory Five forum members in May 2025 reported waiting two to three and a half years for SDR5 units after paying a deposit. Off-road units are sold new as Weddle through Weddle or Rancho.

## Sources

- Weddle MD Series — https://weddleindustries.com/transaxles/weddle-md-series
- Weddle S4/S5 Series — https://weddleindustries.com/transaxles/weddle-s4s5-series
- S4-TRANS, S4 Sequential Shift Transaxle, Complete — https://weddleindustries.com/products/S4-TRANS/S4-TRANS
- S5-TRANS, S5 Sequential Trans, Complete — https://weddleindustries.com/products/S5-TRANS/S5-TRANS
- S4D-TRANS, S4D Sequential Trans, Complete — https://weddleindustries.com/products/S4D-TRANS/S4D-TRANS
- MD2D-TRANS, Weddle MD4-2D Transaxle, Complete — https://weddleindustries.com/products/MD2D-TRANS/MD2D-TRANS
- Mendeola Transaxles — https://ranchotransaxles.com/mendeola-transaxles/
- Fake News (Mendeola transaxles alive and well) — https://ranchotransaxles.com/?p=13241
- Rancho Service — https://ranchotransaxles.com/service/
- Mendeola Cross Shaft — https://ranchotransaxles.com/product/mendeola-cross-shaft/
- MD2D-425 Heavy Duty Front Mainshaft Bearing for MD4-2D or MD5 — https://weddleindustries.com/products/MD2D-425/MD2D-425
- MD-920 Final Drive Seal — https://weddleindustries.com/products/MD-920/MD-920
- MD-945 Heavy Duty Bronze Load Bolt — https://weddleindustries.com/products/MD-945/MD-945
- MD-925 Output Bearing Retainer Plate — https://weddleindustries.com/products/MD-925/MD-925
- Mendeola SDR5 transaxle. This was designed for the GTM — https://supercarbuild.blogspot.com/2012/02/mendeola-sdr-5.html
- AT LAST! — https://www.factoryfive.com/whats-new/at-last/
- Mendeola transaxle thread (archive t-51285) — https://v1.thefactoryfiveforum.com/archive/index.php/t-51285.html
- Mendeola transaxle — https://slc-wiki.squarespace.com/mendeloa-transaxle
- MENDEOLA MD4-2D trans and limited gearing too tall or ok — https://thesamba.com/vw/forum/archive/index.php/o-t--t-662850--.html
- Mendeola MD4S listing — https://racingcarnetwork.com/race-car/mendeola-md4s/
- Mendeola MD5 listing — https://racingcarnetwork.com/race-car/mendeola-md5/
- Mendeola 2D listing — https://racingcarnetwork.com/race-car/mendeola-2d/
- Mendeola MDS4-2D listing — https://racingcarnetwork.com/race-car/mendeola-mds4-2d/
- Mendeola HD4S listing — https://racingcarnetwork.com/race-car/mendeola-hd4s/
- Weddle S5D transaxle listing — https://racingcarnetwork.com/race-car/weddle-s5d-transaxle/
- Mendeola 2D listing (Rancho rebuild January 2026) — https://racingcarnetwork.com/race-car/mendeola-2d-3/
- SCORE Class 1 — https://en.wikipedia.org/wiki/SCORE_Class_1

## Related entries

- Class 1 buggy (desert racing) — https://racingcarnetwork.com/wiki/class-1-buggy/
- VW Type 1 race engine — https://racingcarnetwork.com/wiki/vw-type-1-race-engine/