#1 must do mod asap!!!!!

[chad]

So a few weeks ago i had my check engin light come on. I took it to autozone to have the code ran and was told it was a input speed sensor gone bad. I bought the part for $60 from the dealer and a couple days ago I had my wife take the truck to a transmission shop to have it installed since i'm out of town, in order to install it the tranny has to be dropped as this sensor goes inside, cost $750. I get a call yesterday from the shop and when the dropped it the transmission fluid was a "strawberry milkshake" color and said my radiator had cracked and the transmission fluid and antifreeze had mixed together. it had been sitting in there for at least 3 weeks that i know of but unsure how long before the light came on it had leaked. so i remeber hearing something from TAPD about his H3T and a similar experince so i called him up, same issue. the only really to do is get a transmission overhaul to save itt or otherwise it will be a ticking time bomb, TAPD said his only lasted six months after the incident and his water hadnt been in there as long as mine, so i took his advice to have the tranny overhauled now instead of paying for a service and then down the road have to do the whole thing again. My truck only has 95k miles on it and TAPD said his had 36k miles. The only real solution to keep this from happening is to get an external transmission cooler seperate from the "shared" radiator and tranny cooler. Once this radiator cracks you have no way of knowing its bad until its too late, all said and done this is gonna cost around $2100 for new radiator and transmission cooler and the overhaul. I will be flushing my engine and installing the coolers myself to save an extra $300. So with this terrible lesson learned, and my truck has been taken good care of and maintained well, i highley suggest everyone get that external transmission cooler installed asap to save yourself from a major head ache. from what ive seen they run around $40ish. The factory setup is garbage and no failsafe.

 

[alrock]

Sorry that you had to learn the lesson this way. Apparently , it is common for manufacturers to include the trans cooler inside the radiator but with the abuse our trucks take, the not great design of our radiators and the catastrophic consequences for not doing this mod, many of us have done this.

Keep in mind many variables when doing it. Most of the "calculators" online suggest radiators that are in line with the OEM radiator; you'll want something significantly larger. If you're often in cooler areas I would recommend a thermal bypass to make sure the transmission warms up quickly.

Cotilo's H3 had this happen and the roughest that truck has had it is with potholes outside of the animal shelter. Luckily, she had an extended warranty.

I'm not convinced my trans or engine is cooler now, but I do feel better that I can't experience this "ticking time bomb". I have not been able set up trans temp measurement.

 

[Graham2990]

Wow, that really sucks. Now are people still going ahead and adding aftermarket coolers even after not using the OEM radiator?

The only reason I asked is my radiator cracked at the familiar location on top and was replaced with a new unit.

Do the OEM replacement units have a record of failing in this manner as well?

 

[digglesworth]

I agree with what Alex said. I too added an external cooler with a thermal bypass. Works great. I never had any problems so I did it just for the piece of mind. Learning the hard way sucks... I'm thankful for those who have unfortunately had this happen to them and come up with these solutions. There's no telling how many people's transmissions have been saved by this knowledge. I've heard good things about the silla aftermarket replacement radiators. Much cheaper than an oem radiator. I think you'll still run the risk of the little leaks from the radiator rubbing the support. So try and keep the radiator padded around those spots. I haven't dealt with this firsthand so I'm pretty much just speculating.

 

[Panzer07]

Yupe I had the same happen to me last year luckily it was fix under my extended warranty. After I bypassed the transmission 2 month or so ago...everything was good till about a month or so ago when I got the same problem about the speed sensor...I'm going to just get a rebuilt transmission for 1500 with labor and a 2 year warranty. But first in going to install a new battery and terminals this week to see if that fix it, which I doubt but it doesn't hurt to try specially since I am due for a be battery cables and terminals. Since it is all oem.


Torres

 

[chad]

Alrock-i bought a new radiator, new trans cooler, and a set of electric fans. i never had any over heating issues before this so hopefully running hot wont be an issue, i live in n.c. so no major cold tempts but can get a little cold somtimes. i got the stuff on ebay and will see how it is, do you have any pics of how you did yours? For Graham 2990 i'm not sure how common this is but one time is way more than i ever wanted to deal with. kinda screwed a lot of plans i had up. I would highly recomend this.

 

[High Five H2]

this is on my list. I'm on the fence about electric fans, though.

 

[chad]

this is on my list. I'm on the fence about electric fans, though.

im not taking anything away just gonna add the extra fans, really just because i'll have everything apart anyways installing all the new stuff.

 

[digglesworth]

Check the tech section. Alrock has a good thread with lots of good info...

 

[SuperBuickGuy]

wait wait wait wait wait

change the fluid in your transmission. A transmission normally operates at well above boiling thus whatever water is left will boil out.

I had a turbo 400 (in fact, I might still have it) that I bought from a guy who milkshaked the tranny fluid. I traded for it, and for the first 5 or so miles, it wouldn't shift out of first gear. Cooled down, drove it again to move it on my property (thinking the trans was toast), and by golly it shifted into second. I raced with that transmission for 3 seasons and ran a best of 10.90 and hovered in the 11s range. The transmission still works today. If you drive it and don't let it sit, the transmission will be fine. Just as a motor will be fine as long as you don't hydrolock it (I just replaced the head gasket in my S10, runs fine)... you don't want to run water long, but if you catch it quick enough (and it sounds like you did) there really won't be a huge problem.... no need to swap transmissions... really, no harm, no foul

not a transmission, but I had a 18' flat bottom jet boat that I built and ran a 472 Cadillac motor in - after every winter, the oil would look like a milkshake until after the first run... then it would be fine. I ran that boat for 5 years and never had a problem...

however, if you insist on trans rebuild, get a 4L65e transmission to replace the '60e... same costs, better transmission.

 

[Bigunit]

Sorry SBG, but based on our first-hand experience with my wife's milkshake fried tranny in her H3 (that just about fried her engine if we hadn't caught it in time), I beg to differ. That coolant does quite a job on the H3 drivetrain's gaskets and seals.

 

[rsc]

however, if you insist on trans rebuild, get a 4L65e transmission to replace the '60e... same costs, better transmission.

Physically I know it fits, has anyone done this already? Any computer issues or is it plug and play?

 

[chad]

I already had the guy start it, a new tranny would be nice but its just getting an overhaul. seals where going bad already and sensor went out. i didnt drive it that much as its not a daily driver any more.

 

[SedonaBound]

Do the 3.5 and 5.3 have the same radiator?

 

[rsc]

Do the 3.5 and 5.3 have the same radiator?

Yes, they are the same.

To answer my own question, I have been looking into the 4L65E swap and it is not a strict plug and play swap. To begin with, the output shaft is too large and changing that requires a complete transmission teardown. The oil pan and a few minor bits would have to be changed over from an H3 specific 4L60E (as you would if you got a new 4L60E from a Coly/Canyon or Isuzu). I also believe that PCM/BCM reprogramming would be required but have ideas that it would at least be driveable until tuned.

 

[SuperBuickGuy]

Physically I know it fits, has anyone done this already? Any computer issues or is it plug and play?

there's no external differences, and you'd use the 4L60e controller and case. Simply change the gears inside the transmission.

 

[SuperBuickGuy]

Sorry SBG, but based on our first-hand experience with my wife's milkshake fried tranny in her H3 (that just about fried her engine if we hadn't caught it in time), I beg to differ. That coolant does quite a job on the H3 drivetrain's gaskets and seals.

YMMV - but given the cost difference between a complete rebuild and replacing the transmission fluid; I'd say there's at least one thousand five hundred reasons to give it a shot.

With that said, how could you have fried the engine? ATF is a better cooling fluid then antifreeze.... better on seals too. Need more explanation please.

 

[chad]

YMMV - but given the cost difference between a complete rebuild and replacing the transmission fluid; I'd say there's at least one thousand five hundred reasons to give it a shot.

With that said, how could you have fried the engine? ATF is a better cooling fluid then antifreeze.... better on seals too. Need more explanation please.

TAPD had the same problem, from what he said when the two fluids mix and the heat it began to sorta foam up, his motor got clogged and started over heating causing him to be towed home. Then he had to do a engin flush which when i get back home i'll be doing the flush too before I install the new components. I was going to just do the flush as well, but when talking to TAPD he said he did the flush, and the water set in his for a shorter time, but the detergents already made contact with components inside. He flushed and six months later the damage came and had to go back to the shop for the overhaul. Since my transmission was already taken apart to install the new input speed sensor for the code I recieved, it just seemed to make more since to have it overhauled and eliminate any chances of it going bad in the future. I was already showing signs of damage and paying $750 for a flush this week then a couple months paying $1900 would be a waste of the $750 I paid this week. This is one of those things I never thought much about until it happened to me and is a waste of money to go through on such a pathetic design with a simple fix. Only if I would have paid more attention to why some of you guys did the external transmission cooler. I dont tow to much and never thought much of it.

 

[cory9oh4]

I installed my transmission cooler this week. Super easy and effective!

 

[benlaud87]

Thinking about doing this soon if I ever get time. Does the alpha use the same trans coolers as the i5?

 

[rsc]

The trans cooler is in the radiator, both engines use the same radiator.

 

[Zach]

Do the 3.5 and 5.3 have the same radiator?

They are the same. Only difference would be with a manual trans. The manual trans radiator completely eliminates the trans cooler and it's cheaper than the auto rad. A few guys in So Cal are running it

 

[digglesworth]

if my radiator goes, ill be replacing it with a manual one. my cooler is working pretty good. i hardly ever see temps in the 190s on my scangauge. i thought about doubling up the cooler but i dont think i need to as of yet.

 

[Zach]

if my radiator goes, ill be replacing it with a manual one. my cooler is working pretty good. i hardly ever see temps in the 190s on my scangauge. i thought about doubling up the cooler but i dont think i need to as of yet.

I would replace it sooner than later and not wait till it goes. When it goes, usually it takes the trans out and no forewarning of it going. Local member here lost his at fairly low mileage.

 

[humvee]

Those who have installed trans coolers and are happy with them months on, could you post part numbers, or internet links to your choices?
And also for electric fans if applicable.

Thanks!