Auto Tranny Reliability

JohnnyCash · **Posted:** Sun Feb 24, 2008 8:27 pm

1. Are auto transmissions really fragile?

My friend at work had a Blazer and his garage told him to get it serviced. I told him not to do it because of high mileage and he didn't know when/if it had been done before. He did it and sure enough 2-3 months later we drove to lunch and bye bye transmission.

2. Going up a steep hill you're supposed to use 4-low to prevent over-heating I have read. How steep? I went up a hill over summer that I could have easily done in 2WD, but I put it in 4-low since I had go slow anyway due to it being pretty rough. Do I have to do that?

3. What's up with the vibration when going uphill in reverse? If you did that for 15 minutes straight would the transmission be ruined?

4. I now turn OD off unless on the highway. Is that good or bad for the transmission?

5. How come when a transmission breaks and you have to get a new one it has to be rebuilt. Why can't you get a brand new transmission? It seems like once a transmission breaks you might as well trash the vehicle because the replacement will just break again from the stories I've read.

6. How come so many people get their transmission serviced and then have problems? Why would replacing dirty fluid hurt anything?

That's a lot of questions huh?

tommudd · **Posted:** Sun Feb 24, 2008 8:35 pm

Auto trans are not fragile, they have been using them for years and years, race cars, semi trucks etc use automatics, depends on how they are used and abused. Some are heavier duty of course but still...
as far as using 4 low to go up a hill...IF you are on a very rough and rocky, muddy then yes 4 lo but not that you dont need it.
Not to come off as a jerk, but how long have you been drivng and what have you been used to driving?
If your friends Blazer had high mileage then it may have went if it was serviced or not, telling him not to when youre not sure if and when it was changed was not good
also if I am running around town or pulling a traler in hills I have the OD off if that helps any

tjkj2002 · **Posted:** Sun Feb 24, 2008 8:47 pm

Quote:

5. How come when a transmission breaks and you have to get a new one it has to be rebuilt. Why can't you get a brand new transmission? It seems like once a transmission breaks you might as well trash the vehicle because the replacement will just break again from the stories I've read.

Some auto trannies you can't get brand new since they don't make them anymore.Rebuilding a auto tranny is alot cheaper then new,ussually half the cost if not more.You need to have the tranny rebuilt by a person that truely knows what he/she is doing.Also almost all auto trannies need to be adjusted(electronic or not) after about 500-1000 miles after a rebuild.Most poeple won't take it back and that can lead to early failure.

Quote:

6. How come so many people get their transmission serviced and then have problems? Why would replacing dirty fluid hurt anything?

Improperly servicing,poeple servicing the tranny that have no clue what they are doing,and using the wrong fluid(also to much/not enough fluid) are the main causes.Plus in trannies that have alot of miles on them and haven't been serviced before have clutch material in places that it shouldn't be,thus lowering the fluid PSI,not really affecting the tranny.When cleaned out the pressure goes back to normal and the worn clutch pack can't handle the added stress.Thus servicing your tranny often(at least every 30,000-50,000 miles) by a very quilified person can go along way to keeping your tranny alive for along time.

sleeve84028 · **Posted:** Tue Feb 26, 2008 10:03 am

JohnnyCash wrote:

1. Are auto transmissions really fragile?
2. Going up a steep hill you're supposed to use 4-low to prevent over-heating I have read.
3. What's up with the vibration when going uphill in reverse?
4. I now turn OD off unless on the highway.
5. Why can't you get a brand new transmission?
6. Why would replacing dirty fluid hurt anything?

My take:

1) Not anymore. Maybe years ago when fluid technology was different and clutch materials weren't as refined

2) Under 25MPH [off-road] is when you can use 4-low. There's no point in using it on road to climb a high.

3) I've never tried to back up a hill... I don't think it's a good idea, especially if there is vibration.

4) This will hurt your Mileage but it will not hurt the transmission. Your engine and driveline will spin slightly faster as a result, but no damamge will occur if all parts are properly maintianed

5) You hear the horror stories of bad transmissions. You don't hear about the good rebuilds. Those chain transmission shops are a joke. Go to a local mechanic that specializes in automatic transmissions and you'll be amazed. I had one rebuilt years ago and it was better than new

6) If you don't keep the fluid clean - the dirty particles will actually start to act like a clutch material, holding parts together. When you all the sudden flush out those particles [that were acting like a glue of sorts] the transmission immediately starts to fail as it searches for any remaining clutch material. Proper maintainence is the key to a long and happy transmission life.

Jeepjeepster · **Posted:** Tue Feb 26, 2008 1:16 pm

sleeve84028 wrote:

My take:

1) Not anymore. Maybe years ago when fluid technology was different and clutch materials weren't as refined

2) Under 25MPH [off-road] is when you can use 4-low. There's no point in using it on road to climb a high.

3) I've never tried to back up a hill... I don't think it's a good idea, especially if there is vibration.

4) This will hurt your Mileage but it will not hurt the transmission. Your engine and driveline will spin slightly faster as a result, but no damamge will occur if all parts are properly maintianed

5) You hear the horror stories of bad transmissions. You don't hear about the good rebuilds. Those chain transmission shops are a joke. Go to a local mechanic that specializes in automatic transmissions and you'll be amazed. I had one rebuilt years ago and it was better than new

6) If you don't keep the fluid clean - the dirty particles will actually start to act like a clutch material, holding parts together. When you all the sudden flush out those particles [that were acting like a glue of sorts] the transmission immediately starts to fail as it searches for any remaining clutch material. Proper maintainence is the key to a long and happy transmission life.

Drive-lines spin the same speed no matter how fast the engine is turning.

KJ4ME · **Posted:** Tue Feb 26, 2008 1:35 pm

i have the same viabration when backing up steep hills like in parking lots. dealer said it was normal, i stopped caring. the viabration eventually stops when the car gets going, but initially its pretty violent. i also have never backed up for 15 minutes

sleeve84028 · **Posted:** Tue Feb 26, 2008 1:47 pm

Jeepjeepster wrote:

Drive-lines spin the same speed no matter how fast the engine is turning.

The Input shaft on the transmission side will turn faster. You are correct though, the output shaft will spin at the same speed as OD. I did miss word my response.

JohnnyCash · **Posted:** Tue Feb 26, 2008 4:31 pm

So when I get the transmission serviced probably at 25,000 miles where should I take it?
The dealer or a local mechanic. Should I get flush or traditional?

If a local mechanic how do you know if they are any good? I don't know any friends that have had any good transmission work, so everyone says go to a good local mechanic, but the common person has no clue who is good and who is not.

How would local mechanic check tranny fluid if you need some special tool?

tjkj2002 · **Posted:** Tue Feb 26, 2008 4:42 pm

JohnnyCash wrote:

So when I get the transmission serviced probably at 25,000 miles where should I take it?
The dealer or a local mechanic. Should I get flush or traditional?

If a local mechanic how do you know if they are any good? I don't know any friends that have had any good transmission work, so everyone says go to a good local mechanic, but the common person has no clue who is good and who is not.

How would local mechanic check tranny fluid if you need some special tool?

A tranny flush with the filter change is best.I've seen dealers advertize about $160 for a flush with filter change. I would recommend the dealer unless you can find a AMMCO or really good tranny shop.DO NOT US THOSE QUICK PLACES LIKE JIFFY LUBE,those are bad news places.Also you'll get a warrenty for the work/labor at a dealer.Make sure who ever does it that the tranny uses ATF+4 only(a dealer will only have ATF+4 and knows already,so will a place like AMMCO).

JohnnyCash · **Posted:** Tue Feb 26, 2008 4:44 pm

I was going to go to my dealer, but it sounds like they just don't use the flush machine for some reason.

They said they have one, but they don't use it unless specail circumstances call for it.

Not sure what's up with that.

dieselenthusiast · **Posted:** Tue Feb 26, 2008 7:19 pm

JohnnyCash wrote:

I was going to go to my dealer, but it sounds like they just don't use the flush machine for some reason.

They said they have one, but they don't use it unless specail circumstances call for it.

Not sure what's up with that.

I put a shift kit in mine at 2,000 miles and changed the fluid to Amsoil. I will continue to change my trany fluid every 25,000 miles

Fulltimer · **Posted:** Tue Feb 26, 2008 7:35 pm

#4. With my auto tranny as soon as I go off road I shut off the over drive. Doing so changes my shift pattern to one more useful for off road use.

Terry

dieselenthusiast · **Posted:** Tue Feb 26, 2008 7:55 pm

Fulltimer wrote:

#4. With my auto tranny as soon as I go off road I shut off the over drive. Doing so changes my shift pattern to one more useful for off road use.

Terry

Excellent point, I wasn't for sure if there was an advantage or not. Thanks for clarifying

dieselenthusiast · **Posted:** Tue Feb 26, 2008 7:56 pm

Actually, mine was a "correction Kit" from Transgo for my 2007 KJ, just wanted to clarify :wink:

sleeve84028 · **Posted:** Tue Feb 26, 2008 10:22 pm

tjkj2002 wrote:

DO NOT US THOSE QUICK PLACES LIKE JIFFY LUBE,those are bad news places.

Can you elaborate on this reasoning? I've been using a valvoline to flush my transmission for that last 10 years with no ill effects and am confused by this.

tjkj2002 · **Posted:** Tue Feb 26, 2008 10:30 pm

sleeve84028 wrote:

tjkj2002 wrote:

DO NOT US THOSE QUICK PLACES LIKE JIFFY LUBE,those are bad news places.

Can you elaborate on this reasoning? I've been using a valvoline to flush my transmission for that last 10 years with no ill effects and am confused by this.

Mlost of those quick change places employ poeple that aren't that smart(and 9 times out of 10 not certified to do the work they are doing),ussually charge you for the work and don't do it(Jiffy Lube),usually don't have the correct fluid and put what ever they have in,and usually don't have the proper equiptment to do the jobs they are selling(using the cheapest and worst stuff they can find).

There are some good ones but there are more bad ones then good.They get away with alot of shady stuff because poeple are stupid and don't know anything about there vehicles to know they are getting ripped off.

dieselenthusiast · **Posted:** Tue Feb 26, 2008 10:44 pm

tjkj2002 wrote:

sleeve84028 wrote:

tjkj2002 wrote:

DO NOT US THOSE QUICK PLACES LIKE JIFFY LUBE,those are bad news places.

Can you elaborate on this reasoning? I've been using a valvoline to flush my transmission for that last 10 years with no ill effects and am confused by this.

Mlost of those quick change places employ poeple that aren't that smart(and 9 times out of 10 not certified to do the work they are doing),ussually charge you for the work and don't do it(Jiffy Lube),usually don't have the correct fluid and put what ever they have in,and usually don't have the proper equiptment to do the jobs they are selling(using the cheapest and worst stuff they can find).

There are some good ones but there are more bad ones then good.They get away with alot of shady stuff because poeple are stupid and don't know anything about there vehicles to know they are getting ripped off.

From my experience, Wal-Mart’s tire/lube/express might be safer than a Jiffy Lube “type” of shop. Wal-Mart does not have to worry about a time crunch or money crunch. I’d say that Goodyear Gemini may not be too bad either. Heck, the dealership isn’t necessarily the best either. I’d take it to a reputable mechanic.

Rush345 · **Posted:** Wed Feb 27, 2008 4:35 am

tjkj2002 wrote:

JohnnyCash wrote:

So when I get the transmission serviced probably at 25,000 miles where should I take it?
The dealer or a local mechanic. Should I get flush or traditional?

If a local mechanic how do you know if they are any good? I don't know any friends that have had any good transmission work, so everyone says go to a good local mechanic, but the common person has no clue who is good and who is not.

How would local mechanic check tranny fluid if you need some special tool?

A tranny flush with the filter change is best.I've seen dealers advertize about $160 for a flush with filter change. I would recommend the dealer unless you can find a AMMCO or really good tranny shop.DO NOT US THOSE QUICK PLACES LIKE JIFFY LUBE,those are bad news places.Also you'll get a warrenty for the work/labor at a dealer.Make sure who ever does it that the tranny uses ATF+4 only(a dealer will only have ATF+4 and knows already,so will a place like AMMCO).

I am an AMMCO fan myself years ago blew a tranny in my '95 Dakota, before it was finished I called and said I would supply the ATF they said they only use quality and wouldn't use off brands. My responce was even it it's AMSOIL +4 ATF, with out skipping a beat the owner was like "Ohhhh, I have been wanting to look into that stuff." The tune Changes and Amsoil got used. They showed a willingness to listen. Another strange concept with many a repair house.

sleeve84028 · **Posted:** Wed Feb 27, 2008 8:41 am

tjkj2002 wrote:

Most of those quick change places employ poeple that aren't that smart(and 9 times out of 10 not certified to do the work they are doing),ussually charge you for the work and don't do it(Jiffy Lube),usually don't have the correct fluid...There are some good ones but there are more bad ones then good.They get away with alot of shady stuff because poeple are stupid and don't know anything about there vehicles to know they are getting ripped off.

OK - I was just a tad confused as if they were using the wrong equipment or something. I can understand the 16 year old punk kid who gives a rat's behind about your $25K+ car during the trans fluid exchange. In my case, the shop I use in indendently owned so they carry MOPAR ATF+4, AMSOIL (and a few other brands.)

Thanks for clarifying

Auto Tranny Reliability

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