Why do I think manual transmissions are weaker than autos?

My manual history. 

85 RX7 no issues

78 Jeep CJ V8 no issues

89 M3 no issues, had the normal input bearing noise.

92 525i Close ratio 5 speed, my mom used it for work for a while while she owned it and it needed a throw out bearing.  So it had a fresh clutch under my ownership.

92 Mustang, 100k miles with track time, original clutch.

9? Isuzu trooper, no issues.

My auto history.

78 Nova TH350 behind a 350 no problems

89 4Runner, replaced at 180k.

93 S10 4X4 purchased with a blown front seal leading to a rebuild.

85 Grand National, needed a rebuild and upgrade.

81 Buick Regal, blew the stock trans behind a 455 then added a TH400.  Duh.

2001 GMC 4L60E no issues, added a cooler and corvette servo.

95 Maxima, no issues.

2000 V70 4 speed, no issues after changing the burnt fluid.

2009 Mazda 5 150k and climbing all is well.

2008 Pathfinder V8 125k so far so good.  

I only buy older higher mileage cars.  It looks like I have had better luck with the manuals.  Each auto problem cost me on average $1000.  I have never even worn out a clutch in a manual trans car or had any other related  problem.

Not sure what my point of this is, other than trying to figure out why I am so carful about what car I get with an auto.  When buying a car with a manual trans I don't seem to care what it is.

Oh and I somehow got the title of this backwards.

I think it really comes down to who made it and what era it was built in.

Slushboxes may not be weaker (as in able to handle less torque before something breaks) but they're certainly less reliable and shorter-lasting simply due to being vastly more complicated.

In reply to GameboyRMH :I disagree, my pickup truck had the original untouched( except proper fluid flushes every 65,000 as the owners manual calls for) automatic  

371,000 miles and 20 years!  

Hauled race cars and Timbers  basically enough stone and stuff to build my house.  

55,000 bd ft of Timbers and planks  loaded so heavy the headlights shined on tree tops. 

as much as 6000 pounds of stone per trip  

over mountains through mud  deep snow  

only reason it went to the bone yard is rust. The dreaded tin worm! 

SyntheticBlinkerFluid said:

I think it really comes down to who made it and what era it was built in.

Plus who drove it and maintained it

I broke a gear set on a TH350 once. I was fairly young at the time and 3/4 throttle neutral drops are hard on them. 

That it though. They have all been pretty reliable for me. 

The longest lasting transmission I've ever owned was a Ford E150 with 420K on the original transmission. Other than checking the fluid regularly and driving the crap out of it, I never touched it. 

I am very careful of what autos I'll drive used. Same reason, usually if a manual box has a problem it is either synchros or a clutch, usually neither is a huge deal. Auto boxes are voodoo (yes I know how they work and that they are not really all that complicated, still) and always scare me, new or used.

On the flip side, I have to think that a planetary gear set is stronger than a counter-shaft gear setup, simply because of more contact area on the gears. And the fastest drag cars (normal-ish cars, production based stuff) all run autos. Maybe just because of torque multiplication? or just less time wasted while shifting? IDK. And maybe the autos in question don't last? Still, there is something there I think.

I think the problem is the manuals shift quality goes down dramatically as the synchros wear, which is typically accelerated by people that aren't particularly good at rowing their own gears. 

barefootskater said:

I am very careful of what autos I'll drive used. Same reason, usually if a manual box has a problem it is either synchros or a clutch, usually neither is a huge deal. Auto boxes are voodoo (yes I know how they work and that they are not really all that complicated, still) and always scare me, new or used.

On the flip side, I have to think that a planetary gear set is stronger than a counter-shaft gear setup, simply because of more contact area on the gears. And the fastest drag cars (normal-ish cars, production based stuff) all run autos. Maybe just because of torque multiplication? or just less time wasted while shifting? IDK. And maybe the autos in question don't last? Still, there is something there I think.

I also suspect autos can handle more torque due to their design...I think the reasons they're used in drag racing are the ability to store energy in the torque converter and the quicker shifts.

Still, these things are silly complicated. Just look at this thing:

If I had to choose any object and try to fool people into thinking it's a UFO part, I'd go with this. I've only owned manuals myself but from family and friends' experiences with slushboxes, they seem to be much more trouble-prone in my experience.

When I saw the initial title of this thread, I thought, "Well, most of our customers who are over 1000 hp are running Powerglides." But for a high mileage daily driver, I'm also one giving a lot more scrutiny to automatics.  I haven't had a manual transmission die on me, just the occasional one that needed a new clutch, but my wife and I have had to replace a couple automatic transmissions in various vehicles we've owned.

With manuals, you have the issue of synchro wear.  And a clutch in place of a torque converter, the drivetrain tends to see much harder shock loads, increasing the risk of breaking hard parts.  Autos will wear out clutches, but broken hard parts is fairly rare outside of design flaws or blatant abuse.  

FWIW, the auto in my Jeep is right around 248k.  I burned up a converter lockup clutch around 200k.  It's been both shift kitted and living with more than stock power since about 120k.  And it still shifts great, doesn't slip, etc. and shows no signs of being ready to give up.  

I've been driving a manual as a DD since I learned to drive. In only one car have I had to do any trans work. This was on a '92 Fox Mustang with a T5. Since I bought it used at 50K I have to believe that the PO did most of the damage to it that caused it to start grinding gears on shifts.  I pulled the trans and rebuiltit  myself at 130K.

I did replace the clutch/pressure plate/TO bearing just because I was in there. They could have gone longer but why do a job twice?

A manual transmission may well have worn out bearings and synchros, but if you are aware of the issues and avoid the problem area, you can drive it.  An automatic will generally stop working completely after thw wrong solenoid or valve gets stuck.
 

Modern transmissions are very robust.  Temperature, lubrication or shock abuse will kill either one.

I have driven manuals since I was sixteen, I dd a 5 speed ranger for twenty years, and it was still on its original clutch when I sold it. My wife had the automatic trans die in her monte carlo shortly after we got married, the auto trans went out in my parents minivan, and the auto transmission in 6 cyl Acura is apparently lucky to be alive at 180000 miles. However almost all the drag racers I know run an auto trans.

I've never had either one fail on me.  I have had autos act funny with age due to clogged valve bodies or worn items.  Manuals I've never had issue with.  I've only changed one clutch that wasn't a "while I'm in here" job, and it turned out to still have like 70% life left so I felt pretty dumb.

I search craigslist a lot for cheap cars and my completely unscientific findings are:  There are a LOT of auto cars that "needs trans", while almost never do I see a manual car in need of a transmission.

Additionally, when researching wifecar replacements, it seems the #1 most common major issue and most expensive repair on any risky vehicles was "automatic transmission failure"  (Odyssey for example).

Lets make a list.  Off the top of your head:

What are some cars that are known for manual transmission failure?  

What are some cars that are known for automatic transmission failure?

I could only think of 1 manual, and quite a few for auto.

ProDarwin said:

What are some cars that are known for automatic transmission failure?  

Almost anything with a 4L60E is suspect. 

In reply to Streetwiseguy :

I was thinking the same thing; a worn out manual - syncros, bearings, etc - can still function. Worn out automatics generally leave you stranded.

Automatic transmissions are really interesting and they keep getting better. One of the things I had no concept of before i started rebuilding automatics was how 'loose' they're built. Compared to something like an engine, the tolerance between parts is huge. 

It'd be pretty impressive to build an auto that was more reliable than a well-operated manual, considering how much more complex they are. Most failures in manual transmissions are due to misuse or neglect. If you automate the function of a manual (which already exists of course) it seems to me that you could make one that basically never fails. 

ProDarwin said:

Lets make a list.  Off the top of your head:

What are some cars that are known for manual transmission failure?  

 

What are some cars that are known for automatic transmission failure?

 

 

 

I could only think of 1 manual, and quite a few for auto.

I could name a few. Nissans were notorious for 5th gear pop outs in the 90's FWD stuff and didn't get a ton better early 2000s.

Find me a good  early 8G Civic SI with a factory 2nd gear that isn't notchy. I've never driven one. 

Fox Body Mustang T5 transmissions weren't that great. Only car I blew a transmission in. 

There were a few others but I can't remember off the top of my head. 

The reason Dragsters run Autos is consistency. The ability to trans brake them and not have to worry about clutch engagement. You can just take it to the strip and get consistent results time and time again. 

I want to like autos but I keep buying them from Ford. I did get 30k trouble free miles from my auto Ram before selling it.

I like buying manuals because I feel it's harder to hide problems. I turned down a Mustang because it was making a noise that I thought was the throwout bearing or something in the clutch. Next week I see the ad updated stating the car just had a new clutch installed. I am certainly not the most mechanically savvy, but without knowing the car well I don't feel like I can tell if an auto is in good shape or not from a brief drive. The Ram just felt "right" and I guess I got lucky.

I have friends and family with high mile, trouble free autos though.

In reply to GameboyRMH :

you should outline that and tell people its ancient mayan script 

SI’ve been driving a manual transmission since 1957 and lots of miles on them. I’ve worn out dozens of manual gearbox’s. And kept even more limping along.  

A clutch is a normal replacement item but takes hours to do even on a hoist, forget about doing a newer Corvette!  But my old Corvette with the 4+3 manual transmission needed rebuilding every 50,000 miles no matter how gentle I was shifting it. 

Old Municies used to elongate the bearing holes and your choice was a new case or spend the same amount in machine work. They likely ran out of cases which is why you seldom see one anymore. 

Jaguar gear boxes needed frequent bearings replacement and if not done in time virtually all new gears.  The Moss non synchro 1st was a little more durable than the later all synchro  gear. I suspect the original bearings were better. 

MG?  Lucky to get 100,000 miles if carefully shifted and frequent gear lube replacement.  Forget it if used in racing.  Plenty of race cars have totally different internals used  

Ford? Even the vaunted T5 has a finite life.  Abused and it’s life is plenty short enough.  

In my experience, I have had pretty good luck with autos. I've only blown one... well, snapped the bell housing in half to be exact. When it comes to manuals, I've burned through multiple clutches. I'm sure someone gave me a damn good head start, but I finished them off. I'd say they come out about even, though. I say that because I know how to replace a clutch. I don't know how to rebuild a transmission. I prefer manual, but right now the only street legal manual (and only one that is likely in running condition) is my wife's car. Both my primary vehicles are auto because Crown Vic and Big berkeleying Truck.