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Transmission Problem (...Overheating??)

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Old 09-02-2013, 06:02 PM
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Transmission Problem (...Overheating??)

My truck is a 1994 Pickup DLX 4x4 automatic, with 150,000 miles on it. I do not know if any transmission work has ever been done on it, but all other regular maintenance has (timing belt + water pump, all new seals, plugs, wires, fresh oil change, etc.)

I took my first "long" trip this past weekend, driving from south Florida up to Orlando - about 250 miles/3.5 hours or so. I have made several 45 minute highway trips in the truck with no problems (I go to school at FAU in Boca Raton).

On this trip to Orlando, though, I made it about an hour in (60-70 miles north, give or take) and the A/T Oil Temp light came on. I had only been cruising at about 65 mph. I pulled over right away and let the truck sit for about 15 mins. After that, I hopped back in and the light was off...but came on shortly after being back on the highway. From here I continued my trip at 55 mph and pulled over at every rest stop on the Turnpike. The light would go off after sitting for 15 mins., but never failed to come back on once I was on the road again for 10 mins. or so.

When I got ~45 mins. away from my destination (about 200 miles into the trip) I pulled off at the last rest stop before noticing an even bigger problem - the transmission was having problems going into gear, and when it would "catch," it was slipping. This happened in the parking lot of the rest stop...putting it into Reverse as I backed out of the parking spot; putting it back into Drive when pulling out back onto the highway. Once I got on the highway again it drove fine...even in stop-and-go traffic that I faced when I reached about 15 mins. away from my destination.

I'm not sure if this is standard, but my truck has a small tranny cooler in front of the radiator, in addition to lines running through the bottom of the radiator itself (I understand this truck uses the bottom of the radiator to cool the transmission fluid). I will also note that despite having an oil change done only 2 weeks ago, I was low 2 quarts once I got to Orlando and checked the levels the next day. The transmission fluid showed to be a little low, but just barely below the line on the dipstick.

And with all that said, I just drove it home and had no problems whatsoever; no A/T Oil Temp light, nothing. Didn't have to pull over or anything. Granted, it was much cooler outside (and sun wasn't shining) and it was raining most of the drive...I believe that helped keep the truck cooler in general.

Anybody care to take a shot at what problem(s) I could be having?
Old 09-02-2013, 09:07 PM
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Tranny light shouldn't come on on just a highway... Did you re-gear to lower gears? If so, that could be your problem right there. These trucks tranny pumps are mechanically controlled and don't spin at enough RPMs if/when geared lower to adequately cool the tranny...

Tranny lights on these trucks come on at ~300*F, so you need to change your fluid ASAP. Hopefully your tranny isn't toast, but it might be... A fluid change might protect your tranny, but if fluid's burnt (google for what to look for/smell), your tranny might already be shot and the fluid change be what ultimately kills it...

It sounds like you have the factory towing package, which means you should be even less likely to overheat.

What was your engine coolant temp gauge doing when tranny was overheating? With the ATF to fluid cooler and the factory external cooler before that, it should be more likely that the coolant heats the tranny than vice versa.

This is a good explanation on how our tranny cooling system works: https://www.yotatech.com/forums/f116.../#post52112195
(The rest of the thread will be educational too.)

Mine has the same cooler setup as yours but am planning to change. The system I'm going for is here: https://www.yotatech.com/forums/f2/b...l#post52114064
*And it will cool more efficiently than factory, but -- Big But -- your tranny shouldn't be overheating in the first place.

*To change your fluid, drain the pan and transfer case (not the transfer chain case, but the transfer drain plug up and immediately behind the tranny drain plug). Refill pan w/ funnel at tranny dipstick (3-5 quarts I think). Mark quart lines on a bucket to 15 quarts. Disconnect from out cooler line and put a hose from that hard line in a bucket. Fill another bucket w/ 12-15 quarts fresh tranny fluid and put hose from return cooler line in that bucket. Start truck and shift through the gears, while having someone watch to ensure that it's sucking fluid at same rate it's spitting out. If not as fast, stop and add fluid to pan as needed to balance out... (Draining the pan isn't enough, most ATF is locked up in the torque converter and needs flow flushed.)

Once you flush and determine that your tranny isn't toast, replace the fluid you flushed w/ a quality synthetic like Amsoil ATF. Same process as above, and no reason to waste money on quality fluids if it does turn out to be toast.

All you need to know on flushing types: http://www.gadgetonline.com/TransFlush.htm

And a great DIY on tranny flush (note this is not our gen of vehicle however): http://home.centurytel.net/stevenjac...sh/tranny.html

Last edited by RSR; 09-02-2013 at 09:08 PM.
Old 09-02-2013, 09:18 PM
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I have not re-geared or put on different sized tires. While driving (when the trans light was on), the engine coolant temp was just below the half-way mark, which is where it always is.
Old 09-02-2013, 09:29 PM
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I guess check your fluid for burnt, change it regardless, and then go from there...

It also wouldn't hurt to replace your radiator if it hasn't happened yet (to avoid pink slush, and definitely replace if you're going replace your tranny), but I don't think that's the cause of your issue.
Old 09-03-2013, 12:54 PM
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I just took the truck to a reputable transmission shop, and they said that they found no problems. They said to just keep driving it as there would be no point in spending a bunch of money for no reason. The owner told me that if something happens again, bring it in and then they will be better able to figure it out.

He also said NOT to flush the transmission fluid because I don't know when it was changed last. He said that if it was done routinely (every year/24,000 miles) then changing it would be no problem, but if the fluid is old then all the transmission parts have adapted to that old fluid, and exchanging it for new slick, clean fluid could potentially create a $2,000 problem...
Old 09-03-2013, 07:09 PM
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I've always heard 36-50k, or 4-5 years...

That said, my tranny's been done every couple years since purchase.

Is your fluid brown or black? If not, then it sounds like the tranny shop just wants $2-3k of you back for business in the near future. (And no Aamco, isn't reputable...)

There's various schools of thought on flushing, but the drop pan and inspect, possibly replace filter, and just drain pan and refill pan (multiple times if you so choose, the toilet bowl flush method -- draining pan 3-5 times to where something like 90%+ of your fluid should be new, but gradually) is the absolute minimum I would've expected him to recommend if your fluid wasn't brown. Equivalent to adding ~25-35% new fluid to the tranny mix to ensure at least minimal lubrication so that it doesn't burn itself up...

Definitely make sure you actually looked at the reference links provided. This is the fluid life left after your ~300*F tranny temp light went on (yes, that's just 1500 miles):
AUTOMATIC TRANSMISSION FLUID LIFE / TEMPERATURE RELATIONSHIP:

Automatic transmission oil can provide up to 100,000 miles of service before oxidation requires replacement, at an operating temperature of 175° F. Above this temperature, the oil oxidation rate doubles with each 20° degrees F increase in oil temperature. See chart.

ATF DEGREES F - MILES OF SERVICE
175 - 100,000
195 - 50,000
215 - 25,000
235 - 12,500
255 - 6,250
275 - 3,125
295 - 1,500
315 - 750
335 - 325
355 - 160
375 - 80
395 - 40

Note: Transmission oil and filter should always be changed more frequently when driving with heavy loads (RVs), typically at least every 25,000 mile intervals, since converter outlet temperatures then normally far exceed the ideal 175° F.
https://www.yotatech.com/forums/f2/b...l#post52079990

Properly lubricated w/ fresh fluids, these trannies should easily go 300k miles...

Last edited by RSR; 09-03-2013 at 07:20 PM.
Old 09-03-2013, 07:22 PM
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Changing fluid and filter VIA Trans oil pan access will not damage the transmission.
-Designed to be serviced.

Check for any air obstructions near the Auto Trans fluid cooler(s).

Dirt and debris in radiator/trans cooler(s).
-CLEAN!

Fluid cooler lines damaged/restricted...?

Any extra loads in/on the vehicle..?
-Excessive Weight on board..?
Old 09-03-2013, 07:29 PM
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Also, it might not be sheer profit motive. They might be worried about changing fluid in a trouble transmission and then you coming back and trying to take them to small claims court claiming that they ruined your transmission...

Good call Kiroshu -- failing/collapsing/pinching soft lines are a possibility. If from factory, those hoses are near rock hard now and at end of life... And pressure could collapse and they're unlikely to spring back fully.

Last edited by RSR; 09-03-2013 at 07:32 PM.
Old 09-03-2013, 07:31 PM
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^-- X2

A lot of scared TransAxle Repair shops out there.
Old 09-03-2013, 07:31 PM
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After leaving the shop, I went home, changed, and left for work. I live about 5 miles/10 mins. East from this shop. On my way to West to work (I pass this shop every day) the transmission started acting up again - I was at a red light, and when it turned green I tried to accelerate but the truck wasn't going. The RPMs raised and the truck rolled forward, but only as fast as it would if I were not pressing on the gas at all (idle). I blipped the throttle and re-applied the brake, and then tried to go again and it started driving fine. I called the shop right away, continued West and dropped the truck off at the shop...

Originally Posted by Kiroshu
Changing fluid and filter VIA Trans oil pan access will not damage the transmission.
-Designed to be serviced.

Check for any air obstructions near the Auto Trans fluid cooler(s).

Dirt and debris in radiator/trans cooler(s).
-CLEAN!

Fluid cooler lines damaged/restricted...?

Any extra loads in/on the vehicle..?
-Excessive Weight on board..?
Ok. They were closing when I dropped it off, so they said they will call me first thing in the morning. I will ask him about re-checking the fluid level and changing it if necessary (I tried checking the level again but it wasn't clear what I was looking at. The level looked low, but there was fluid all the way up the dipstick - like it "brushed" itself on there as I was pulling it out...was hard to tell where the actual fluid level line was).

There are no restrictions in front of the oil cooler or radiator, nor is there any debris. Both these were checked for when I got to Orlando and parked the truck.

Also inspected all the lines that ran in/out of the transmission, and they seemed to be in good shape as well.

No extra load in the vehicle - just myself, 1 duffle bag, and some misc. items.
Old 09-03-2013, 07:35 PM
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Originally Posted by RSR
Also, it might not be sheer profit motive. They might be worried about changing fluid in a trouble transmission and then you coming back and trying to take them to small claims court claiming that they ruined your transmission...

Good call Kiroshu -- failing/collapsing/pinching soft lines are a possibility. If from factory, those hoses are near rock hard now and at end of life... And pressure could collapse and they're unlikely to spring back fully.
The guy did say that "it isn't uncommon that people bring in vehicles with old transmission fluid, and end up calling back after it is changed saying it's more f****d up than ever." He then proceeded to add "there is no point in changing it to give yourself a potential $2,000 problem that you don't have right now" (that's when he was telling me they didn't find anything wrong when it was hooked up to their scanners and after they drove it around a little; told me to just take it home and not worry about it, but if something else happened then bring it back and they may be able to find a culprit).
Old 09-03-2013, 08:02 PM
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Checking the Automatic Transaxle fluid in these trucks is fairly simple.

-Engine must be operating temperature and idling in Park/Neutral.

-Vehicle must be on a level surface.

-Remove fluid level stick and observe the fluid level in the "Hot" range when fluid level is normal.

Last edited by Kiroshu; 09-03-2013 at 08:04 PM.
Old 09-03-2013, 09:33 PM
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Originally Posted by Kiroshu
Checking the Automatic Transaxle fluid in these trucks is fairly simple.

-Engine must be operating temperature and idling in Park/Neutral.

-Vehicle must be on a level surface.

-Remove fluid level stick and observe the fluid level in the "Hot" range when fluid level is normal.
I did, but like I said it was hard to tell where the fluid level was at. The dipstick isn't lightly colored/reflective like the oil dipstick is; it is dark, so any fluid is harder to see. And like I also said - the length of the dipstick and the way it tightly fits into its slot makes me believe that fluid on the walls of said slot brush off onto the full length of the stick.

From what I saw, it appears to be low...at the "Cold" level when the engine was hot. I am going to have the shop confirm this for me tomorrow...

What is the consensus with this though? If it is low, do I have them add more? Do I have the replace the fluid from the pan, but not have it flushed? Since there is a good chance the fluid is in fact burnt, should I just have them flush it?
Old 09-03-2013, 09:39 PM
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If the fluid's burnt, odds are you'll need a rebuild. Sorry dude.

If they don't recommend an immediate rebuild, I'd drain and fill the pan at an absolute minimum.
Old 09-03-2013, 10:24 PM
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Originally Posted by RSR
If the fluid's burnt, odds are you'll need a rebuild. Sorry dude.

If they don't recommend an immediate rebuild, I'd drain and fill the pan at an absolute minimum.
Anybody care to share what a fair, "ballpark" price on a rebuild would be?
Old 09-04-2013, 08:53 AM
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Shop called me this morning and said that the torque converter was shot, and all the "soft parts" inside the transmission were also shot. Fluid had pieces in it and obviously needed to be flushed out and replaced as well.

He said they get factory torque converters, but they have been upgraded/updated since 1994 and are now a better design, and they cost $307 or $370 or something like that.

He said the rebuild parts are also more "heavy duty" and "better" than the parts installed in 1994, which would make the transmission as a whole better than it was originally. He said the parts and labor for this was around $1,600. He also noted that if I were to buy a new transmission with these same parts/specs it would cost ~$3,500 to do so, and a rebuilt one would be ~$2,900, but he wanted to "help me out." Lastly, he stated that the transmission - once rebuilt and with a new torque converter - will give me better fuel economy and make the truck a little more "ballsy" since it will be shifting properly and the torque converter working as it should, which hasn't been the case up to this point.

So the total price ended up coming to $1,990 + tax, but he said that if I paid cash they wouldn't charge me tax. I told him I didn't have that much money, and I was more able to find a ride for a few months than to find the money this would cost now...so he asked me "how much do you have?" I told him $1,400-$1,500 was my absolute maximum, and "after talking with (his) boss" he said they can do $1,600 whether I pay cash or card. This is apparently what they would have charged as a wholesale price; they do all the local police's cars' transmissions, as well as other companies with work trucks and such. He told me they would just write up my receipt as a wholesale service to help me out and get the discount.

I told him again that $1,500 was all the money I had to my name, so he said they will let me pay the $100 difference in a month..."trusting (me) to do the right thing by just stopping in when (I) have it and pay." They said that they always try to do the right thing and be honest, and helping me out with the price was proof of that...and that they would just like for me to return the favor by being honest and paying what I owe when I am able, and to spread the word about a pleasant experience with their shop. I thought this was a nice gesture.

Last edited by KtrainHurricane; 09-04-2013 at 09:01 AM.
Old 09-04-2013, 11:17 AM
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Sounds right on price. Trannies are like engines where a bunch of different issues are going on that affect price... Anywhere from $1000 to $3000 is in the fair range. Anything more than that you're ahead to buy a new fully remanufactured tranny (prob anything above $2500 actually when considering warranty and extent of overhaul for remain vs repair of tranny) w/ a 3-5 year warranty on it. Typically the clutch packs are what goes w/ bad fluid. The torque converter burning itself up is common too...

These are pretty common transmissions btw, so I'm sure they'll be able to fix it right.

Keep up w/ your fluid from now on though! And even if paying cash, make sure you get some sort of receipt/warranty for the work!

Last edited by RSR; 09-04-2013 at 12:13 PM.
Old 09-04-2013, 04:43 PM
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Interesting how the first time you brought the vehicle to them they stated that the Transmission had no problems and to just keep driving it....

Now apparently on your second visit the Transmission has severe internal damages...?

-Just saying.
Old 09-04-2013, 07:48 PM
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Originally Posted by Kiroshu
Interesting how the first time you brought the vehicle to them they stated that the Transmission had no problems and to just keep driving it....

Now apparently on your second visit the Transmission has severe internal damages...?

-Just saying.
The first time all they did was drive it themselves, and hook it up to the scanner. Once I left (because they told me to just keep driving it and not worry about it), I took my 5 mile drive home, changed for work, and headed out again...that is when the transmission started slipping.

This is two instances that I personally have had it slipping on me, so I don't doubt that there was something wrong with it. Perhaps it just wasn't heated up enough to start acting up when I brought it there the first time
When it went in for the second time it was later in the same day.

Maybe I got taken, maybe I didn't. I don't know. Not much else I can do now about it though. It will be finished tomorrow morning and is going to cost me $1,600. With the amount of things I've had go wrong with this truck in the past month alone, I am really just over all of it. If $1,600 more is what it takes for me to comfortably be able to drive this around as my DD and not have it break (or worry about it breaking), then so be it. Sucks, I know, but there isn't much else to say...
Old 09-06-2013, 01:53 AM
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No fluid check? Wowser.


Last edited by RSR; 09-06-2013 at 01:54 AM.


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