RCN Wiki · Parts & Spares

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

By the RCN editorial team · Updated November 2026

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.

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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 ¹. The early MD4E kept the Type 1 layout; one Samba poster calls it a Type 1 case on steroids ¹⁹. The later MD4-2D moved to a G50-style 300M input shaft. It became the volume seller for LS-powered long-travel sand cars ⁶⁷.

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 ¹². 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 ⁸. 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 ⁵⁷.

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 ¹⁶. 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 ¹⁵. Early SLC builders noted it needed a specific starter and that real-world data was thin ¹⁸.

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 ¹⁷. For the off-road MD and S-series, Weddle and Rancho are the practical suppliers today ²⁹.

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 ². Rancho lists Mendeola units for engine outputs up to 1,500 hp, which covers Class 1 and sand-drag use ⁹. 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 ²⁷.

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.

Versions and evolutions

Version	Years	What changed	How to identify
MD4E	late 1990s to 2000s	First MD four-speed; VW Type 1 derived case with Mendeola 10-inch ring and pinion. Shares its ring and pinion with the 2D but keeps the older input. A Mendeola dealer called it adequate for street and strip; a 2D was only needed for low-eight-second cars. ¹⁹	Type 1 style nose cone and shift rod; MD-series seals and load bolt fit it. Ask the seller for the Rancho or Weddle build sheet, because the case looks much like a 2D.
MD4-2D / MD4S-2D	2000s to present (Weddle built since 2013)	300M G50-type input shaft (1 in x 23 spline), 10-inch spiral bevel R&P in 3.88, 4.86, 5.14 or 5.43, bronze load bolt, billet side covers. Current kits ship with the XDC main case. ⁶	Four-speed synchro box about 2 inches narrower than a VW Bus transaxle; 930 flanges standard, 934 optional. Shipping weight 126 lb. Look for the Weddle MD-TRANS pick sheet or a Rancho invoice.
MD5	2000s to present	Five-speed on the MD architecture, 10-inch R&P in 4.86, 5.14 or 5.43, mid- or rear-engine. Sold as a dual-purpose sand and desert box. ⁷	Longer gear carrier than the 2D; same front mainshaft bearing (Weddle MD2D-425) as the 2D. A used example on RCN was described as having a Deca case.
S4 / S5 (Mendeola, then Weddle)	2000s; Weddle-built since 2013	Sequential ratchet shift, 85 mm shaft centres, full-size reverse, 10-inch R&P in 3.56, 4.63, 4.86 or 5.14, 1-3/16 in x 18 spline input, 934 flanges standard. Weddle revised castings, shift mechanism, oiling and the mainshaft bearing retainer. ³	Dual-lever or ratchet shifter, dash gear display port, billet side covers, VW top-starter, VW side-starter or Chevy bellhousing. Shipping weight 180 lb (S4) or 190 lb (S5).
S4D / S5D	2010s to present	Same gear stacks as S4/S5 under an 11.5-inch Klingelnberg R&P (4.63 or 4.88), GM 1-1/8 in x 26 spline input, Chevy LS bellhousing for an 8-inch triple or 9-inch twin disc clutch. ⁵	Visibly larger final-drive housing and LS bellhousing; shipping weight 200 lb. Listed by Rancho as the complete bolt-in LS package.
SDR5 (street, Stage 1 and Stage 2)	November 2011 to present	Five-speed for mid-engine street kits (Factory Five GTM, Superlite SLC). Quoted 650 hp / 600 lb-ft. Later units use GM-style clutch parts and a standard Corvette clutch; width is close to a Porsche G50. ¹⁵	Mendeola-branded, not Weddle; LS bolt pattern; needs a specific starter (SDR IMI-140 or Powermaster 9509). Stage is on the build invoice, not the case.

Known issues

Input and front seal leaks — Oil film on the bellhousing after a trip. One SDR5 owner needed two seals; the leak stopped only after the seal bore was lightly sanded before the second fit. USD 18 for a final-drive seal; labour extra ¹⁷
Front mainshaft bearing on MD4-2D and MD5 — Weddle sells a high-capacity seven-ball CX11 replacement for this bearing, which tells you the standard one is a known weak spot. Ask whether the heavy-duty bearing went in at the last rebuild. USD 44 part, plus a strip-down to fit it ¹¹
Ring gear deflection and load bolt wear — The bronze load bolt stops the ring gear walking under load. A worn bolt lets the gear mesh open up; noise under power is the usual sign. Weddle sells a heavy-duty bolt for all MD, S and HV units. USD 34 part; a new ring and pinion is far more if the mesh has been run loose ¹³
Clutch cross shaft and bushing wear — Sloppy or sticking clutch release, especially with hydraulic slave cylinders. Rancho sells a heavy-duty cross shaft with arm, heim linkage and new bushing as a direct replacement. unknown; Rancho quotes by phone ¹⁰
Mainshaft bearing retainer on pre-2013 S4/S5 — Weddle upgraded the mainshaft bearing retainer when it revamped the S4/S5 in 2013. Older Mendeola-built units may still carry the original part; ask the rebuilder. USD 22 for the output retainer plate; retainer work needs a strip-down ²
Gearing too short for the use — Sand ratios (4.86 to 5.43) run out of road fast. A used MD5 on 4.86 behind a 2.4 Ecotec on 35-inch tyres topped out near 104 mph. Street MD4-2D owners use the 3.88 R&P. A ring and pinion swap is a full rebuild; budget accordingly ²¹
Long lead times for new Mendeola-built units — SDR5 buyers in 2025 reported waits of two to three and a half years after paying a deposit. Used units therefore sell quickly. n/a ¹⁷

Checklist 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. ²
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. ⁷
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. ⁵
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. ⁶
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. ²⁶
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. ¹⁷
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. ⁴
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. ³

Running costs ⁹

Rebuild interval	No published interval. Sand-car owners rebuild on noise, leaks or a ratio change rather than hours; several RCN sellers advertise a rebuild done within the last twelve months.
Typical rebuild cost	Rancho does not publish Mendeola rebuild prices and quotes by phone. Wear parts are cheap: final-drive seal USD 18, HD front mainshaft bearing USD 44, HD load bolt USD 34, retainer plate USD 22. A new ring and pinion or gear set is the big ticket.
Consumables	LAT Racing gear oil is supplied with new Rancho units; sequential units are often run with a pump and cooler.
Spares availability	Good. Weddle Industries stocks gears, R&P sets, bearings, seals and shims for MD4E, MD4-2D, MD5, S4/S5 and S4D/S5D; Rancho is the main rebuilder. Mendeola's own website is offline (parked, November 2026).

Where it races today

SCORE World Desert Championship · Class 1 (unlimited open-wheel) — No transaxle restriction. Engines normally aspirated, 500 hp or more, about 3,500 lb dry on 37-inch tyres. S4D/S5D territory. ²⁷
SCORE / MORE / BITD · Class 10 and limited buggies — Weddle's S4/S5 page shows a MORE PCI Class 10 winner from 2021 on the S-series. Check each series rulebook for current transaxle rules. ²
Sand drag and dune use · Open — The MD2D-DRAG with aluminium spool and the MD4S-2D for LS sand cars are sold for this use; no sanctioning rules apply. ⁷

Market prices

Weddle MD4-2D complete, new, list price: 10,995 USD (2025-11) ⁶
Weddle S4 sequential complete, new, list price: 16,495 USD (2025-11) ³
Weddle S5 sequential complete, new, list price: 17,495 USD (2025-11) ⁴
Weddle S4D (11.5-inch R&P, LS bellhousing), new, list price: 18,495 USD (2025-11) ⁵
Mendeola SDR5 bare, new, Factory Five GTM: 10,950 USD (2012-02) ¹⁵
Mendeola 2D, used, refreshed 3/2025 with Weddle parts, 4.86, 930 flanges, RCN asking: 4,500 USD (2025-08) ²²
Mendeola MD4S complete LS bolt-in kit, used, rebuilt, Orem UT, RCN asking: 6,200 USD (2025-09) ²⁰
Mendeola MDS4-2D, used, Jackson MS, RCN asking: 6,800 USD (2025-08) ²³
Mendeola HD4S, used, ratios 2.79/1.84/1.35/1.04, RCN asking: 7,100 USD (2025-09) ²⁴
Mendeola MD5 five-speed, fresh rebuild with new mainshaft, 4.86, New Orleans, RCN asking: 8,300 USD (2025-08) ²¹
Weddle S5D with LS bellhousing, unused, 4.88, shifter and gear display, Bethel CT, RCN asking: 15,300 USD (2025-09) ²⁵
Mendeola 2D, 934 flanges, Jamar Pro X shifter, Rancho rebuild January 2026, 5.43, RCN asking: 6,000 USD (2026-07) ²⁶

Between August 2025 and July 2026 used MD-series units on RCN asked USD 4,500 to 8,300. A fresh Rancho or Weddle rebuild is the main lever on price. Unused S5D stock asked about USD 15,300 against a USD 17,495 to 18,495 list price, so savings on sequential units are small.

Reference prices are dated and sourced; live asking prices are in the listings above.

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, Weddle Industries (2025) — 1996 start of MD program, Weddle exclusive producer since 2013, Type 1 basis, 10-inch R&P, XDC case
Weddle S4/S5 Series, Weddle Industries (2025) — Originally Mendeola S4/S5, 2013 revamp, sequential, upgrades to casting, shift mechanism, oil flow, bearing retainer; 2021 Class 10 winner photo
S4-TRANS, S4 Sequential Shift Transaxle, Complete, Weddle Industries (2025) — Price USD 16,495, 180 lb, R&P and gear ratios, input shaft, flanges, case construction, shifter options
S5-TRANS, S5 Sequential Trans, Complete, Weddle Industries (2025) — Price USD 17,495, 190 lb, applications, pre-drilled oil system, ratios
S4D-TRANS, S4D Sequential Trans, Complete, Weddle Industries (2025) — Price USD 18,495, 200 lb, 11.5-inch R&P 4.63/4.88, LS bellhousing and clutch sizes, GM input spline, bronze load bolt function
MD2D-TRANS, Weddle MD4-2D Transaxle, Complete, Weddle Industries (2025) — Price USD 10,995, 126 lb, R&P 3.88 to 5.43, gear options, G50 input, 930/934 flanges, 2 inches narrower than Bus
Mendeola Transaxles, Rancho Performance Transaxles (2025) — MD4S-2D, MD2D-DRAG, MD5, S4S, S4D prices, ratios and intended applications; LAT oil supplied; synchro or Pro-Shift
Fake News (Mendeola transaxles alive and well), Rancho Performance Transaxles (2023) — 2012 purchase of manufacturing rights by Weddle, rebranding, Rancho as main service centre, 2D rebuilt with new gears, synchros, sliders and R&P
Rancho Service, Rancho Performance Transaxles (2025) — World's largest Mendeola builder claim, engine outputs to 1,500 hp, rebuild steps, pricing by phone
Mendeola Cross Shaft, Rancho Performance Transaxles (2025) — Heavy-duty cross shaft replacement with arm, heim linkage and bushing for hydraulic slave cylinders
MD2D-425 Heavy Duty Front Mainshaft Bearing for MD4-2D or MD5, Weddle Industries (2025) — USD 44.07, seven-ball CX11 upgrade bearing
MD-920 Final Drive Seal, Weddle Industries (2025) — USD 17.85, fits MD4E, MD4-2D, MD5, S4/S5, LQ6, HV, PBS
MD-945 Heavy Duty Bronze Load Bolt, Weddle Industries (2025) — USD 34.24, fits MD, S4, S4D, S5, S5D, LQ6, HV, Albins AGB, PBS
MD-925 Output Bearing Retainer Plate, Weddle Industries (2025) — USD 21.70, fits MD4E, MD4-2D, MD5, S4/S5, HV
Mendeola SDR5 transaxle. This was designed for the GTM, Supercar Build blog (2012-02) — 650 hp / 600 lb-ft rating, USD 10,950 price, master shift and gear display prices, target car weight and layout
AT LAST!, Factory Five Racing (2011-11) — First GTM transaxles shipped 17 November 2011, deposits a year earlier, 2 to 3 units per week
Mendeola transaxle thread (archive t-51285), Factory Five Forum (2025-05) — SDR5 Stage 1/2, waits of 2 to 3.5 years, front seal leak and fix, Corvette clutch, G50-like width, starter clearance, retirement remark
Mendeola transaxle, Superlite SLC wiki (2012) — SD5 first street unit, GTM group buy, late deliveries early 2012, SDR IMI-140 starter
MENDEOLA MD4-2D trans and limited gearing too tall or ok, TheSamba.com (2016-09) — MD4E as Type 1 case on steroids, shared R&P with 2D, 3.88 street ratio, 4.86 and 5.14 sand ratios, dealer comment on 2D for low-8s cars
Mendeola MD4S listing, racingcarnetwork.com (2025-09) — Asking USD 6,200, complete LS bolt-in kit, rebuilt a month before listing, Orem UT
Mendeola MD5 listing, racingcarnetwork.com (2025-08) — Asking USD 8,300, Deca case, new mainshaft, 4.86 R&P, 104 mph on 35-inch tyres behind 2.4 Ecotec
Mendeola 2D listing, racingcarnetwork.com (2025-08) — Asking USD 4,500, refreshed 3/2025 with Weddle parts, 4.86 R&P, 930 flanges, rear-engine setup
Mendeola MDS4-2D listing, racingcarnetwork.com (2025-08) — Asking USD 6,800, Jackson MS
Mendeola HD4S listing, racingcarnetwork.com (2025-09) — Asking USD 7,100, ratios 2.79/1.84/1.35/1.04
Weddle S5D transaxle listing, racingcarnetwork.com (2025-09) — Asking USD 15,300, unused, LS bellhousing, 4.88 R&P, Weddle shifter, gear display, oil pump for cooler
Mendeola 2D listing (Rancho rebuild January 2026), racingcarnetwork.com (2026-07) — Asking USD 6,000, 934 flanges, Jamar Pro X shifter, LAT oil, Rancho rebuild 13 January 2026, 5.43 R&P
SCORE Class 1, Wikipedia (2024) — Unlimited open-wheel class, normally aspirated engines of 500 hp or more, 37-inch tyres, about 3,500 lb dry

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 ¹.
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 ¹⁶.
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 ³.