At $520 shipped, the Midlands rebuild kit is an excellent value, especially when you consider MINI charges over $600 for the mainshaft alone & $200 to $300 per gear..
The Midland in the MINI shares over 80% of it's parts with the Midlands R65U ("U = "uprated") that was used in the Rover 200/25 sedans. Rover went belly up about seven years ago but there are still a lot of Rover parts being sold in the UK. Some of the kits are using these Rover parts. That's not necessarily a bad thing, just make sure the vendor will guarantee that the parts unique to the MINI version are included in the kit. Here are the changes BMW/MINI made to their version of the Midlands R65:

Uprated gear selector forks.
The Mini version has three contact pads where the fork contacts the selector hub, one at each end of the fork & one at the top. The Rover forks have two contact pads.

Synchros
MINI machined first and third gears to accept a more modern three piece synchro. The synchros are sintered metal (not brass)& are fiber lined. They have almost double the friction contact area so they are much better than the one piece Rover versions.
MINI replaced the 4th & 5th gear plain metal synchros with one piece fiber lined versions. For some reason, MINI made no changes to Second gear. It's identical to the Rover R65 & uses the same one piece plain metal synchro. I recently ordered one of these from a UK Rover parts house. With shipping it cost $65. The exact same part in MINI box costs $310.

See the attachment below showing the Synchros used on the MINI. Top- three piece synchro used on 1st & 3rd, lower left- plain metal synchro used on 2nd gear . All five of the Rover synchros look like this. Lower right- one piece fiber lined synchros used on MINI 4th & 5th gear.

Final Drives
The later Rover sedans came with 3.76 & 3.70 final drives. Our MINIs use a 3.94.
You can tell what you're getting by counting the number of teeth on the output shaft pinion & the differential ring gear. The MINI has a 16 tooth pinion & 63 teeth on the ring gear ( 63 divided by 16 = 3.94) Rovers used 17/64 & 17/63 versions. The taller Rover gearing will hurt your acceleration but would help reduce highway cruising RPM & probably MPG. Check with the vendor to confirm what you're getting! Luckily, these parts don't have a high failure rate so you can usually reuse the Ring & pinion from your MINI R65.

With no end float adjustments & few special tools required,the Midlands is one of the easiest boxes to rebuild. The pre-assembled kits make it that much easier. Getting it out of the car is the biggest part of the job. Use the best bearings you can find, particularly the front input shaft bearing. SKF, ***, Timken & Koyo are good quality.

When I rebuilt my R65 i weighed the clutch parts:

Stock clutch disc 1lb 12oz
Stock pressure plate 6lb
Stock R50 flywheel 17lb
Fidanza R50 flywheel 7lb 15oz

Reducing (or adding ) rotating weight can have a dramatic impact on performance!

 

hi,am also having issues with my 5 speed.does anyone know if it's possible to replace it with a 6speed?

 

Yes it all depends on where you live. Way Motor Works can do it, I have heard Texas Speed has also, and of course Chad has down at his total MINI & BMW shop in Charleston.

 

Here's a good rundown.

"Fixing the Weak Link" PDF from Texas speedwerks is a must read, as are the various forum threads on the subject.

I went with the $600 rebuild kit because it's a far cheaper solution than the other options, and you don't need to know much of anything about transmissions to do it. But it might only last 30k to 50k miles. Of course if you can lay your hands on a 6 speed for a reasonable price, I'd say do it.

 

hi,just found out that what i thought was a hub bearing issue is actually my trans going bye bye.my r50 has 110,000 mostly highway miles on it and was told i need a new trans.does anyone have any experience with the rebuild kit that minitransmissions.com is selling?can i just replace this trans with a 6 speed getrag from a s model?????

 

I've just bought a 04 MC which was built in June missing the swap to the Ford transmission(Puma/Ka) which I was told happened in July. So it looks like I have the Midland (Peugeot) transmission with 125,000miles on it. Seeing as I'm going to rally the car I'm going to rebuild the tranny to be safe. The good thing is there are some really low final drives for this tranny which is better for me. I currently run a Swift GTI which has similar tranny woes once the power is increased but I cope with that with an annual rebuild. Looks like I'll be doing the same with the Midland. Going to 6 speed is not allowed in the rules plus the final drive is to high.

 

There are a few racing Peugeot 106's in the UK that use the MA5 boxes. They are running anywhere from 150 to 220bhp. The good news is that the Rover/MINI version has some improvements over the MA5.
The Swift is a cool car. I thought I read somewhere that the Swift uses a Gbox from the same MA5/R65 family. Is there any truth to this?

 

Gordon,

How can you tell if I have the Midlands tranny? My MC is June 04 but before I start ordering stuff I need to be sure. The rebuild kit sounds good value but I plan to use a really low final drive from Gripper LSD. http://www.davemacprops.com/dmpgripperapplications.html Yes the Swift GTI is a still a fun car with really nice engine, I don't think the tranny is MA based but looks similar the Mini tranny internally.

Thanks the coversion formula to find out the final drive. You can see Gripper do a 5:1 FD which is good for what I need.

 

The switch from Midlands to Getrag in the R50 (MC) took place in 7/04, so you're
pretty close to the switch. You should have a Midlands with a 6/04 build date, but
I wouldn't bet the farm on that without looking and confirming visually.

Look at these pics: the GS-5 65BH is the Midlands
the GS5-52BG is the Getrag.

http://www.realoem.com/bmw/partgrp.d...14&hg=23&fg=05

 

Thanks Cristo I have the Midlands by looking at your link as I have smooth end cover like the top drawing.

 

The bell housings look very different, the Getrag/IB5 has the slave on the bottom & the Midlands has the stamped rear cover for the Fifth gear(s). The Midlands also has that clutch fork lever on top that looks like it was made by a Medieval blacksmith.

A 5.1 FDR plus 15's should make for snappy acceleration! In addition to the Gripper plate LSD, Quaife makes at least two coated gearsets plus an LSD for the Midlands/MA box. The downside (apart from cost!) is that they don't address the Synchro sleeve & hub wear on the Midlands and they use the single piece synchros
(MINI uses 3-piece on 1st & 3rd).
The 220bhp Pug is running "polished" gears & a steel caged front input bearing. I'm guessing the polishing is ISF/REM refinishing. The bearing is easy to source in the states & doesnt cost much.
There are some reliability improvements you can make to the Midlands. If interested, I can post more detailed info on what I encountered in my research & rebuild.

 

Gordon, I'm interested in any info as I been spending some time on the Pug forums looking at MA5 box options. All I need is the gearsets to last a year as I do a rebuild after every season. Cost is going to be the limiting factor as the rally Pug gear sets go for arounf 3500 UK pounds which gets me into a 6 speed conversion. I prefer a short ratio 5 speed as Costa Rica does not have any long straights. I run a 7000rpm in 3rd most of the time in the Swift. Done 4th a few times and that's with a 4:4 FD.

 

The Midlands has a few weak areas that can be easily improved. This post will start with the bearings.
The stock Front input bearing is a shielded design with a reinforced brown resin cage & 8 ball bearings. The shielded side prevents debris from entering the bearing but it limits lubrication. There is an oil passage surrounding the outer bearing race, but it does not supply oil to the inner cage & roller *****. At the recommended 2 quart level, the oil barely covers the bottom of the outer race. If the oil level drops, the bearing can rapidly overheat & seize.

Here are some replacement choices:
SKF# 6205 is a steel caged 9-ball bearing. It's an open design (no shield) but it would be a good choice for a race box that gets frequent maintainence & oil changes.
SKF # 6205-2RSL is a sealed, 9 ball bearing with a steel cage. The seals are a low friction design. This is the bearing I used. Cost ranges from $15-20 USD
SKF # 6205-2RSH is a sealed 9 ball bearing with a steel cage. It would be acceptable for street but might not be the best choice for racing. The seal design produces more friction, limiting it's max RPM to 8500.

SKF # 6205-ETN9 is often used as a heavy duty bearing replacement for MA-5 boxes. The MINI bell housing has a narrow machined groove that helps locate the input bearing. (inner groove ID is 1.825") You can see the groove if you look closely at the bellhousing pics. The Peugeot doesn't have this locating groove. When test fitted it didnt sit properly . I would not use this bearing in a MINI unless the groove is remachined to fit.
Probably the ultimate option for racing would be to use a roller bearing on the input side. Roller bearings have over twice the load strength of a typical ball bearing. This what the Midlands uses for the front output shaft bearing. SKF makes a 52 x 25 x15 NJ205 bearing that might work. The drawback is cost ($90-95 for the bearing alone) plus machining costs. FWIW, the early Alfa Romeo FWD 164's had a similar problem with it's SNR input ball bearing. Alfa's solution was to provide an upgraded "overload" bearing. The replacement was an SKF NJ series roller bearing.

For the other shaft bearings, the standard SNR bearings seem to hold up well. If you want to use SKF they can be tough to find, but here are the ones I was able to get:
Front Output -roller bearing SKF # BC1-0013DD
Rear Output - sealed ball bearing w. snap ring SKF #BB1B-447244

Timken makes the stock differential side bearings. They're high quality. I wouldn't hesitate to use them. When ordering, be sure to specify a normal (N) clearance bearing. Many bearing supply houses stock these bearings with larger internal clearances for use in very high RPM electric motors (C3,C4 C5 spec) You don't want excess clearance in your front input bearing
There are other bearing brands that may also work. Fast Track bearings in the UK sells a complete set with steel caged input plus the box seals. I don't know who makes the bearings.
Next post will cover some ways to improve oiling & decrease gear & synchro wear .

 

The casing looks so much like the Suzuki Swift it's scary! I have bearing supplier because I use top quality bearings in the Swift. The information you supplied is very helpful, looking forward to more. Thanks again.

 

Speaking of the casing, I discovered that the rear gasket was blocking off part of the oil supply passages. If I hadn't dry assembled & test fitted the rear cover I never would've spotted this.

The fifth gear pair sits in it's own compartment on the back of the trans. On the Midlands, the fifth gear cover is made of stamped metal & sealed to the main case by a thick rubber gasket. The gasket is meant to be installed dry, no sealant is used. The attachment holes for the housing allow it & the gasket to be moved by up to 2mm in several directions. That's enough to partially block the oil passages. When reassembled to the original wear marks, the gasket was blocking a third of the oil supply passage area. I'm not sure how they aligned them at the factory (in my case, not very well !!) but the only way to do it properly is to test fit the cover before bolting the main casing to the bell housing, then mark the gasket position on the outside of the casing when it's aligned. A sharpie marker worked fine for me. A better way might be to install a hollow locating dowel in the side oil hole to position the gasket.
The casting finish in the oil holes & supply trough was pretty rough so they were smoothed with a grinder & polished. The output shaft(mainshaft) oil supply hole for 5th gear was also rough. I removed casting flash, chamfered & polished it. The insides of the main case were also polished to promote better oil flow back.

Counting two others I acquired for parts, this is only the third Midlands I've taken apart. But on all of them, there were specific areas that showed significant wear. The worst wear was on a transmission that smelled as if GL5 (Hypoid) gear oil had been used. The synchros were also stained a dark brown. My transmission showed the least dog & synchro wear of the three. FWIW, I match revs on the downshift, don't speed shift & It's been run on Redline MTL for most of it's life. The actual gear teeth on all looked good, but the engagement dogs on the gears (especially 2nd & 5th) showed a lot of wear. Unfortunately, the dog teeth are cast onto the gear. If they are worn down, the gear is a throw away. Wear on the dogs makes for difficult & crunchy shifting. The sharper the edges on the dogs the smoother the shift. See the pic below comparing a new 2nd gear & synchro to worn examples.
The 2nd & 5th synchronizer sleeve & hub assemblies showed moderate to heavy wear on the inner sleeve teeth & the hub splines. The hubs seem to be a softer metal & their finish looks different, as if they were not heat treated. Other parts showing high wear were the input & output shaft lock tabs & the differential side gear shims. The box run on Hypoid oil had very bad differential shim wear.

To improve the fatigue strength, the gears, hubs & shafts were dual shot peened. This is a standard & relatively inexpensive stress relief process that's been used for many years. Dual peening is different from the process that is normally done to engine componants. If you have this done, be sure to request they mask the bearing surfaces on the shafts & the top of the 2nd gear. The Midlands 2nd gear has a sprayed on friction coating where the synchro cone sits on it (like a 1960s MGB). You don't want this coating removed! The same parts also received a Tungsten disulfide (WS2) treatment. This is a dry anti-friction coating. There are many specialty business's that offer these services & a lot of technical info online. I paid $290 but you may be able to do better. Other commonly used gear treatments are ISF/REM polishing & the newer WPC metal treatment from Japan. WPC is the most expensive of these but it may be the best. Google these & you'll find some very good info on them. Cryogenic treatment is another alternative but there is some debate over it's merits.

My R50 is only mildly modified with just 6000 miles on the rebuild so time will tell how effective the mods are! I'm considering building up the better spare box with some additional mods. If I do, I'll post details.

 

Almost forgot. Replacement clutch forks have started to appear on EBay. If you get one, compare it carefully to your original. I got one that had a bent arm. when assembled, the throw-out bearing was binding on the clutch guide sleeve. The vendor replaced it so no issues.
There is a very good post on removing this fork in the NAM 1st Gen problems forum.
Here's one last pic of the back of the Gbox housing & gasket.

 

Thanks for taking time to write this info. The Suzuki box is much the same with the same woes but getting gear parts is not so easy. My second has the worn teeth on the synchros but still shifts ok. I swap the MTL every 2 rallies with only the oil darkening when I first fitted the gripper LSD. I worked out the 5:1 final drive give me a top speed of 112mph with 60 series tyre and a 20mph difference between each gear. If 65 series tryes fit I can use those for the gravel and gain a little ride height. If I can get the box to handle 6 rallies and a years brisk road driving I will be happy.

 

Gordon.

I have found a cylindrical roller bearing with the same dimensions as a 6205. $136.92ea sir with a bronze cage or $47.42 with the plastic/resin cage

 

Can't say I've seen a bronze caged cylindrical roller bearing before. If you're running close to stock HP, an uprated Ball bearing would probably do just fine. I recently stumbled across 'Microblue' bearings. They are offering an improved 6205 ball bearing. Their ad copy sounds very much like it's a WS2 treated bearing.

If you do go with a roller bearing, definately consult with a bearing company engineer or a racing transmission specialist. Roller bearings are stronger than ball bearings when it comes to radial loads but are more sensitive to axial / thrust loads. Some roller bearing designs are better at handling axial loads than others. Check out the design of the Getrag 5-spd front bearing.
You may need a different amount of preload with a roller bearing.
There are some good companies that specialize in modding problem transmissions like the the VW020, Mazda, Mitsubishi FWD & Subaru transaxles who might be willing to assist. MetricMechanic modifies BMW 5-speeds using tapered roller bearings. Click on the transmission link on their web page for details.
Unfortunately, I don't know of any MINI specialists who offer these type of services for the Midlands. Good luck with the project

 

Thanks for the info , as you say maybe a good ball bearing will do. I was thinking of using a 12V oil pump and oil rail to supply oil to the top bearing and gears. I found several on the internet. Alos I'm going to drill a hole and plug it in the top of the gearbox as a filler for the oil as i did with the Suzuki. Makes quick filling of the oil after an axle pops out!

 

The oil spray bar sounds promising, should make the front bearing very happy! I like the top fill idea. You can fill thru the reverse switch hole ( just takes 30 seconds to remove the switch) but it's slow going thanks to the reverse gear arm.
I noticed about 1/2" below the normal filler hole, there is a cast boss on the diff casing. It's level with where the output shaft main oil hole is. It might be a perfect place to install a sender for an oil warning light on the dash. When you have the box apart you'll see what I mean.
An inexpensive mod is to fit additional magnets. I used two large magnets from a GM Transmission part# 12386078. One on the bottom of the 5th gear housing & one for the floor of the main case, plus a 'dimple' magnet for the drain plug. One of the many things I never got around to was fitting a temp sender. Would be interesting to see what the high temps are.

What's the standard prep for your Group N axles & joints? Treated stock or uprated?

 

I thought about removing the reverse switch but knowing my luck I'd break it! Another Suzuki thing is there are several magnets in the box so it won't harm to fit something similar to the Midland. Actually I changed the oil last week finding only iron filings on both drain plug magnets which was a surprise. The box shifts really well so I hope I have rare good box??? hahah Regs for Group N in Costa Rica is pretty laid back, Any thing is possible as long as it's not Dog box.

 

My Mrs car is an '06 R50 and on just 91k kms and its had 2 replacement trannies! 1 @ 48k kms (just before we bought it) and we just had another at 89k kms :( The latter also cost me a flywheel and clutch for obvious reasons.....

 

Gordon,

Doing rebuild on 03 Midlands (126K miles) due to differntial backlash noise. Roller bearing at pinion has more play than roller skates I had as a kid. Ring and pinon look fine. Looking to replace all bearing. Saw your listing for bearing part#'s Any SKF# for rear input bearing or differntial bearing+race?

Any source for just the 3rd-4th "forged" bronze shifft fork? MINI and others sell complete set for $300+ (industrial drum of Vaseline not included). MINI has none (complete sets) in States but can get mid-October. All other forks look good but 3-4 one is half worn into tabs and also into "meat" of fork. Other forks and gears/syncros look fine with the exception of a slight wear on the syncro portion on 5th gear. Any idea what causes wear on 3-4 fork or especially on 5th gear? The internals look remarkably good given the mileage. The culprit appears to be the pinion bearing, but may as well change the other while in there.

Anybody have torque specs for case fasteners (internal and external)? These appear to be self tappers, however, not hardened as the 3 lower ones on bottom of case sheared. What do you guys use to seal case halves (appears tMINI uses some type of silicone? Was thinking about using hylomar. NO! not looking to swap to Getrag 5 or 6 due to cost. Recently did clutch about 5 months/11K miles ago due to throw-out bearing "evaporation" leaving 3 unbroken clutch diaphragm fingers (so I have been "educated" for the second go round at trans removal/install). Removed "lifetime" lube and install Redline MTL along with Hyperlube (which I think saved total distruction the past 3 months since noise started). Only other issue was a running PS pump with key in hand (great internal pictures of pump that I may post later). Wife loves car as she practically lives in it as a traveling occupational therapists...so I have to keep it going to keep her happy. Anyone's info/advice would be apperciated.

 

Get your torque specs and other info from the PDF Rover Manual. Download from
http://www.rover-coupe.com/rcoc/inde...verhaul-manual

I'd email Mini Gearboxes and as them for the parts you need. See:
http://www.minigearboxes.co.uk/#/contact/4536273531