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Mazda B2300 Trans. and Diff. questions.


pentiuman

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Hi! Newbie here. I'm trying to identify my transmission and differential and do some maintenance – change fluids, and maybe the differential cover. TIA! Why I want to be sure I do everything right: I previously had a 92 Ranger, 4cyl., w/ (probably) the Mazda M5OD-R1 manual transmission. I did a lot of work on the truck, including transmission removal, cleaning, new throwout bearing, starter ring gear, u-joints, put in expensive synthetic ATF. I put everything back together thinking I’d have this truck for a long time. Right? No. Within about a year, the manual transmission fried from a fluid leak! I had no idea that it was leaking anything significant, (must have leaked mainly once warmed up and while moving). Since the truck had other issues, and I didn’t want to mess with the transmission again, it went to the junkyard.

I replaced it with my current truck, a 97 Mazda B2300, 4cyl., 7.5 RG differential, 5spd manual transmission. (Chosen, since it shares some of the same parts that I kept, like starter, A/C, battery, alternator, etc.) Questions:

1. Does my Mazda B2300 have the M5OD-R1 transmission? TRS’s Terms Page states, “"R1" refers to the Mazda built "M5OD-R1" transmission introduced in 1988 and is the ONLY manual trans used in rangers from 1993-on (and from 1988-1992 only 2.9 engines could be equipped with the "other" manual transmission)”. Under Ford Ranger Manual Transmissions – TRS states, a transmission code of “M” indicates a Mazda M50D-R1 transmission. It also says,
“This is a top shift fully synchronized transmission. This has a light duty aluminum case and has a rectangular shape casting ribs with a large top cover. The R-2 is known for leaking oil from a rubber plug in the top cover. You should replace the rubber plug with a steel Dorman cup plug P/N 555-108 or Dana P/N 219-3052. You will need 3 plugs. These transmissions often melt down due to the oil loss caused by these plugs.”

2. Is “R-2” above a typo or were there several revisions of this transmission (R-1,R-2,R-3,R-4)?

TRS has a page under Numbers, Federal Sticker (On Your Door), called “Understanding the Safety Compliance Label (Federal Sticker)”. The lower section of my door sticker on my Mazda B2300 has the following:
WB | BRK | INT TR | TP/PS | R | AXLE | TR | SPR
108 B 3X 5/ Z 86 M AR

3. So, does the “M” under “TR” indicate an Mazda M50D-R1 transmission? It’s a little confusing because (as shown above) my sticker looks different and has some different ID codes than those for Rangers, and TRS doesn’t list Mazda specific codes.

4. Shift Rail Plugs – To prevent another transmission meltdown, TRS states you can either buy new rubber plugs, new metal plugs, or put RTV on them. However, member fordwheelinman said the metal plugs they got were too small (they didn’t specify if they had the exact Dorman or Dana plugs listed above though).

5. If I have the M5OD-R1 transmission on my Mazda B2300, is it correct that I use a Mercon ATF fluid, and if so, which revision (not V)? The last time I had to add fluid to a manual transmission (92 Ranger), it was very messy and the location of the fill hole made it difficult. More than once I almost drank fluid. I had an old gear bottle pump tool that I tried to use, but the old, inflexible hose kept coming off. I then bought a tube to go on the ATF bottles, and it also wouldn’t stay on. What specifically do you guys use?

6. I also want to replace the differential fluid and cover to make things look nice. The tag on my differential indicates it’s a 7.5 Ring Gear. Are the covers for the 7.5RG and the 8.8RG differentials the same? O’Rielly’s Auto Parts and Advance Auto Parts both sell a Dorman differential cover, part# 697-702 (that comes w/ a gasket), but state that it’s for a 8.8RG! They also both sell just a Felpro gasket alone, which states it’s for a 7.5RG (like mine), but if the 2 covers are different, why don’t they sell the 7.5RG cover?

7. Do I have a locking differential and need to add a friction modifier or any different fluid in my differential than Hypoid Gear lube 80W or 90W?

8. Is it better to use a gasket, or RTV or both? I did a search on TRS on this subject, which wasn’t very helpful, as I even found someone who said Rangers didn’t come with differential gaskets for several years now. (AFAIK - wrong). Why do some suggest RTV when a specific gasket is available for about $4? (just preference, laziness, or ?)

Thanks! - By the time I finish something, I'll be the expert on it!
 
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exbass94

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1. Does my Mazda B2300 have the M5OD-R1 transmission? TRS’s Terms Page states, “"R1" refers to the Mazda built "M5OD-R1" transmission introduced in 1988 and is the ONLY manual trans used in rangers from 1993-on (and from 1988-1992 only 2.9 engines could be equipped with the "other" manual transmission)”. Under Ford Ranger Manual Transmissions – TRS states, a transmission code of “M” indicates a Mazda M50D-R1 transmission. It also says,
“This is a top shift fully synchronized transmission. This has a light duty aluminum case and has a rectangular shape casting ribs with a large top cover. The R-2 is known for leaking oil from a rubber plug in the top cover. You should replace the rubber plug with a steel Dorman cup plug P/N 555-108 or Dana P/N 219-3052. You will need 3 plugs. These transmissions often melt down due to the oil loss caused by these plugs.”
Yes, you have an M5OD. Pretty much ALL of them are known for the leaking plugs.

5. If I have the M5OD-R1 transmission on my Mazda B2300, is it correct that I use a Mercon ATF fluid, and if so, which revision (not V)? The last time I had to add fluid to a manual transmission (92 Ranger), it was very messy and the location of the fill hole made it difficult. More than once I almost drank fluid. I had an old gear bottle pump tool that I tried to use, but the old, inflexible hose kept coming off. I then bought a tube to go on the ATF bottles, and it also wouldn’t stay on. What specifically do you guys use?
Mercon is the stuff to use. Mercon V is supposed to completely supercede regular Mercon, but some members have reported poor shift quality with it. Regular Mercon is still widely available. I use one of these pumps:


6. I also want to replace the differential fluid and cover to make things look nice. The tag on my differential indicates it’s a 7.5 Ring Gear. Are the covers for the 7.5RG and the 8.8RG differentials the same? O’Rielly’s Auto Parts and Advance Auto Parts both sell a Dorman differential cover, part# 697-702 (that comes w/ a gasket), but state that it’s for a 8.8RG! They also both sell just a Felpro gasket alone, which states it’s for a 7.5RG (like mine), but if the 2 covers are different, why don’t they sell the 7.5RG cover?
No the covers are not the same. There's a 99.999% chance you have the 7.5 axle. Click here to find out what axle you have

7. Do I have a locking differential and need to add a friction modifier or any different fluid in my differential than Hypoid Gear lube 80W or 90W?
You most likely don't have a limited slip. (use that link above to see if you do) If you do, you need some friction modifier. Some gear oils, like Valvoline Synpower and Mobil 1 already have the friction modifier mixed in.
8. Is it better to use a gasket, or RTV or both? I did a search on TRS on this subject, which wasn’t very helpful, as I even found someone who said Rangers didn’t come with differential gaskets for several years now. (AFAIK - wrong). Why do some suggest RTV when a specific gasket is available for about $4? (just preference, laziness, or ?)
I use Ultra Black RTV on diff covers. I've heard the gaskets are leak-prone, but have no experience with them. The RTV works nicely.
 

pentiuman

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Thanks exbass94 - and any future posters!

- Yeah, thanks for your considerable feedback and info.! Everything you said was great - thanks - but your link to a grease pump apparently isn't working. If you know a brand name, drop me a line. Thanks again.

- Your advice will save me some time and money from buying the wrong diff. cover. I'll be putting Mercon ATF in my manual trans., gear fluid only in my diff. and using some black high temp RTV I already have on the diff. cover. Also, planning to try to access the top of the 3 leak-prone transmission plugs from inside the cab - though there's no sign of a transmission leak at this time from underneath. Underneath of most of my truck is clean.

Now I'm just waiting 3+ or so weeks for the KS weather to get warmer, before changing the fluids, to get more of the used stuff out (fluids as warm as possible). Since I couldn't find a 7.5RG diff. cover readily, I'm also going to need a warm day or so, to be able to paint my own diff. cover after some rust sanding, rust conversion and priming. - I did this last year on my Trans Am diff. cover and it still looks as good as new. Thanks!
 

exbass94

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The pump I was talking about is like a soap dispenser pump that screws onto the bottle.

 

pentiuman

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Thanks again exbass94!

- I'm in the process of changing the diff. fluid and painting the diff. cover over the next 2 days. For painting, I have been sanding the (outside) top rust off, and have some rust converter spray, and special heat resistent paint that can go over rust, w/out requiring a primer either. (I lightly sanded the inside of the cover perfectly clean).

For filling the diff., I already had bad experience with the pumps, so I bought a turkey baster, then found a plastic syringe-like tool at Walmart, used to precisely mix gas and oil for lawnmowers, etc. Had to let the bolts soak overnight w/ WD40. Last night, re-discovered that the fill plug took a square 3/8 extension as I thought, and that it wasn't fitting when I first tried it, likely due to rust buildup.

My '97 B2300 has 125k on it, (street only) and my dirty diff. fluid was a light coffee brown color, w/ a very, fine buildup of what was metal over the years, but churned into a grayish, creamy butter-like consistency paste on the magnetic fill plug. On the inside of the diff. cover, I used paper towels to wipe the darker soot-like fluid residue off. I'm gonna use brake cleaner spray to get it spotless. I don't know how many miles the fluid was in there, but as far as I'm concerned, the "lifetime" of the fluid was about over and time for a change.

The different gears inside the diff. looked fine for this amatuer, and only light wear anywhere - no chunks of metal, and no sign of heat or water damage AFAIK. I'm glad I'm not doing anything complicated for off-road stuff. I'll leave the fun in the dirt /mud for the rest of you guys!

- Thanks again for your advice.

pentiuman
 
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pentiuman

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I know member exbass94 thinks I likely don't have a limited slip axle. I suspect he's right, due to the extreme trouble I have getting around in snow (or even rain)! I know nothing about differentials or axles, but anytime I'm stuck, seems like just my pass. side rear wheel spins? Can anyone explain to me the simple difference between having a limited slip differential and not? (Are both rear wheels driven, but the difference is the characteristics during different traction scenarios???) I've looked at the Differential and Locker Info at: http://www.therangerstation.com/tech_library/LockerComparo.html VERY HELPFUL! I wish all manufacturers provided animated pictures for their mechanical devices like this.

So, in the next day or two, while my rust converter "paint" is drying, I'm now trying to positively determine whether I have a limited slip differential or not (to know which gear lube to add - i.e. friction modifier. I already have 1 qt. w/ the additive in it, and 1 1/2 quarts without.) Again, it's a 1997 Mazda B2300, 4cyl. 5-spd. Some references state it's a Dana style rear end, whatever that means. I have the axle tag in front of me:
S370F
373 75 7A10

Besides having a 373 gear ratio, and a 7.5 Ring Gear, the axle ID in the Tech Library doesn't seem to have Mazda codes (S37OF)! Guess I need to go to the library and check out a repair manual, if nobody on here knows. TIA

Edit: Why does gear oil smell so bad and are the vapors flammable?

Edit 2: The Federal Door Sticker / Safety Compliance Label has "86" under the Axle column, which http://www.therangerstation.com/Magazine/Summer2009/federal_sticker.htm indicates is an open 7.5 diff. Not sure why the axle tag doesn't have this same #?
 
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AllanD

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The rubber plugs always "weep" a little as they are the transmission "Vent"

and whatever tiny ammount of oil is on them is blown out when the air in the trans warms up.

But even replacing them with solid metal plugs the trans still burns up....

Because the oil was REALLY leaking from either the tailshaft seal
(and through the weep groove in the gasket suface where the
trans mates to the T-case)

OR the oil is blow overboard as hot vapor after the shifter bushings fall apart and block the oil feed to the pocket bearing.

Frankly I think the rubber plugs get blammed for a whole hell of a lot more
than they can actually cause...

I've actually discovered one plug MISSING (it fell the F' out!)
and yet the trans still had oil in it....

The thing is that the weeping plugs cover up the evidence of the other leakage.



AD
 

exbass94

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Some references state it's a Dana style rear end, whatever that means. I have the axle tag in front of me:
S370F
373 75 7A10

Besides having a 373 gear ratio, and a 7.5 Ring Gear, the axle ID in the Tech Library doesn't seem to have Mazda codes (S37OF)! Guess I need to go to the library and check out a repair manual, if nobody on here knows. TIA

Edit: Why does gear oil smell so bad and are the vapors flammable?

Edit 2: The Federal Door Sticker / Safety Compliance Label has "86" under the Axle column, which http://www.therangerstation.com/Magazine/Summer2009/federal_sticker.htm indicates is an open 7.5 diff. Not sure why the axle tag doesn't have this same #?
Those two things tell me that you definitely have a Ford (not Dana) 7.5 rear end with 3.73 gears and an open diff (no limited slip). Rangers never came with Dana rear axles. Front axles yes, but not rear. And gear oil smells bad mostly because of the sulphur in it.
 

xeris

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Mercon is the stuff to use. Mercon V is supposed to completely supercede regular Mercon, but some members have reported poor shift quality with it. Regular Mercon is still widely available.
I have had that exact experience. Ran Mercon V for less than 1K. Shifting became hard with a bit of grind going up or down through the gears, like the synchros were worn out. Drained and re-filled with Dex/Merc (couldn't find straight Mercon) and that fixed the issue. The short time the Mercon V was in the trans there was a lot of metal on the drain plug and the fluid that drained of had a distinctive metallic reflection to it. Some damaged happened. How much only time will tell.
 

crazypj

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That's real handy to know.
I think I'll return the Mercon V I just bought and use regular Mercon instead
I haven't re-built a transmission since 1990 and would prefer not to do it
Guess the search function is going to get some use :icon_thumby:
OK, did some hunting about, there is no reason Mercon V should cause problems.
The spec and additive package is superior to 'standard' Mercon
I ended up on 'Bob is the Oil Guy' site then went through several pages before deciding starting at earliest would probably be more productive
Found 'comparison between Mercon V and Mercon.
Don't know is it's 'bad form' to post links to different sites but this could be useful?
http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=497371#Post497371
 
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xeris

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It doesn't make any sense to me. I too have been up and back on the different Ranger forums and also to Bobs'. As you stated V is supposed to be superior. The only thought I can offer is from an experience I had some years ago with a Honda Prelude. The trans axle called for Honda 30w trans oil (has a specific name which I can't remember). It worked much better than regular motor oil of the time and a lot better than newer motor oils that have friction modifiers in them. The reason that was generally accepted on the model specific forum was the motor oil was too slippery for the synchros to work at the optimum, and/or the Honda oil had something in it that made the synchros work better. I this sounds a bit ignorant but this was my and many others experience. I do know this, I will never use Mercon V in my Mazda 5sp trans again.
It's never bad form to reference information that furthers learning and understanding.
 
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