Puzzled and a Trans Question

[Jim]

I’ve had this truck 2 years & 21,000 miles. Today I found a coolant spot 3" dia. under the front of the truck (tasted it coolant fur shur). The drips were coming off of the tie rod dripping from the wiring harness that goes to the crank position sensor. With my trusty mirror & flashlight I went on a search to find no coolant anywhere but there. All hose connections were tight & dry, thermostat housing, dry, I couldn’t see the weep hole or the pass side water pump to block underside. Yesterday I didn’t use the vehicle at all it was a 40-degree day with wet snow & mist. I have found in past experiences with that humidity, leaks can be more apparent. I’ve used the truck today since & not a drop?????

On another note the brake fluid is dark & scrungy…time for the turkey baster fluid change.

Also do you guys think I should have the trans flushed or just do the filter myself…the fluid looks & smells bran new?

[kwalsh]

IMO, I would change the tranny fluid and filter. The properties of ATF are just too important to be tested using the taste and smell method.
ATF that has lost it's ability to do its stuff won't show immediate signs of age. I don't think a flush would hurt the tranny, as long as the system used doesnt use too much pressure....something that won't blow out any seals. Synthetic ATF is the way to go.

I too had coolant that seemed to sweat out somewhere.
The level hasn't changed in the res. tank, but I did notice something that could be signs of the coolant breaking down or maybe rust?

[HenryJ]

I’ve had this truck 2 years & 21,000 miles. Today I found a coolant spot 3" dia. under the front of the truck (tasted it coolant fur shur). The drips were coming off of the tie rod dripping from the wiring harness that goes to the crank position sensor. With my trusty mirror & flashlight I went on a search to find no coolant anywhere but there. All hose connections were tight & dry, thermostat housing, dry, I couldn’t see the weep hole or the pass side water pump to block underside. Yesterday I didn’t use the vehicle at all it was a 40-degree day with wet snow & mist. I have found in past experiences with that humidity, leaks can be more apparent. I’ve used the truck today since & not a drop?????

Look for your Dex leak at the front of the intake manifold (Head to intake interface is common , I'm told) . A UV light can be helpful. It intensifies the color of the coolant. A simple fluorescent black light bulb can be used.

I hate to throw the "Dex bashing" into this, but it may be a contributing factor. Look for the crusty crystals and waxy sludge forming anywhere air might meet coolant (recovery tank, rad. cap. leak?)

If you have not changed the coolant yet, DO IT NOW. Dex will not go the five years. You can just drain/flush and refill with new extended life coolant (pink), or make the switch to green , it is your choice and preference.

... I should have the trans flushed or just do the filter myself…the fluid looks & smells bran new?

Change the filter your self then take it in and have them flush/exchange the fluid.

[Jim]

Thanks for the info, it looks like I'm in for some mantenance expence. I don’t want to do the coolant change until I am sure if there is a leak. I’m not sure if the dealer will fix it under the warranty if I changed the coolant. As far as the trans fluid if they are replacing the fluid should I go synthetic or not & will my Chevy dealer use syn if asked.

[killian96ss]

IMO, I would change the tranny fluid and filter. The properties of ATF are just too important to be tested using the taste and smell method.
ATF that has lost it's ability to do its stuff won't show immediate signs of age. I don't think a flush would hurt the tranny, as long as the system used doesnt use too much pressure....something that won't blow out any seals. Synthetic ATF is the way to go.

IMO synthetic tranny fluid is a waste of money and will probably cause your tranny to burn the clutches up. The reason I say this is because I have had 3 different transmissions fail due to synthetic tranny fluid. All 3 trannys burned up their clutch packs. The 3 trannys I am referring to are a TH400, 4L60E ( same tranny in our trucks ), and an automatic in a Mazda 626. I have told by 2 different transmission shops that the synthetic fluid is too slippery causing the clutches to slip more than they should and creating more heat. I'm not saying that this will definitely happen, it's just a word of caution.

[AZS10Crew]

I've always heard that synthetic tranny fluid was bad as well. Don't bother with it.

[kwalsh]

sythetic has come a long way in the past few years. A friend of mine worked for Castrol & Mobil on synthetic oil & ATF.
The viscosity and thermal breakdown properties of the synths outperfrom
traditional fluids.

Syth being too viscous...it can't be in order to meet the SAE grades.

[killian96ss]

sythetic has come a long way in the past few years. A friend of mine worked for Castrol & Mobil on synthetic oil & ATF.
The viscosity and thermal breakdown properties of the synths outperfrom
traditional fluids.

Syth being too viscous...it can't be in order to meet the SAE grades.

I would agree that synthetic motor oil is much better than traditional oil, and in fact I use it on all my vehicles, but the synthetic ATF has blown up 3 of my trannys, and the cause was directly linked to the ATF. Every transmission shop that I've talked to has warned me about synthetic ATF. IMO the synthetic works better in every area of the transmission except the clutch pack. Look at what the manufacturers say about their synthetic ATF, and I'll bet one of them says smoother shifting. When I used synthetic AFT ( Mobil ) in the 3 trannys that I lost, I can say they did shift more smoothly than before, but this is also what caused the clutch packs to fail prematurely. In all 3 transmission the fluid had turned very dark with lots of clutch material in the pans.

[kwalsh]

I wonder if it has something to do with these GM cluth packs.
I need to get ahold of this guy and ask him what trannys they tested with. I don't remember.
Since you had bad luck with the synth ATF,
I'll be keeping a close eye for the slightest change in color.

[killian96ss]

I wonder if it has something to do with these GM cluth packs.
I need to get ahold of this guy and ask him what trannys they tested with. I don't remember.
Since you had bad luck with the synth ATF,
I'll be keeping a close eye for the slightest change in color.

I also wonder what sort of test the oil companies do with their synthetic ATF. Like I said earlier, at first the tranny does seem smoother and does shift better, but after about 10k miles is when the problems started. The worst failure was with the Mazda 626 tranny, so I don't think it's isolated to just GM trannys. I hope they do some sort of longevity test and not just a quick analysis of how the tranny shifts and performs.

[Jim]

I wonder if it has something to do with these GM cluth packs.
I need to get ahold of this guy and ask him what trannys they tested with. I don't remember.
Since you had bad luck with the synth ATF,
I'll be keeping a close eye for the slightest change in color.

I also wonder what sort of test the oil companies do with their synthetic ATF. Like I said earlier, at first the tranny does seem smoother and does shift better, but after about 10k miles is when the problems started. The worst failure was with the Mazda 626 tranny, so I don't think it's isolated to just GM trannys. I hope they do some sort of longevity test and not just a quick analysis of how the tranny shifts and performs.

My wifes 97 German car has a ZF transmission. It states you must use synthetic VAG fluid, Dextron will do permanant damage, yet the same car in 95 called for dextron.

[quickbiker]

Maybe the coolant just came out of your overflow.

[Jim]

Maybe the coolant just came out of your overflow.

I considered that, Monday night the wife sent me out for fasnachts...fat tuesday was the next day. I may have come flying in the driveway over the bump enough to slosh that overflow bottle enough to spew dex.

[Jim]

I found the leak. The truck sat from Sat. night until today, when I found a small spot under it. The thermostat housing gasket is it. Maybe now is the time to put the Jet 180 degree stat in. Or will my service engine light come on?

[HenryJ]

You should be OK, if you do not make any other changes to the cooling system.

Keep a close eye on that Dex!
It may turn to "river water/jello" at any moment

Remember that it is contaminated by air. GM's line is that poorly maintained vehicles run low on coolant are the cause of their woes

[2bunik]

I have the same leak in the same spot.. I dont remember if I pointed it out to you henry j

[HenryJ]

I have the same leak in the same spot.. I dont remember if I pointed it out to you henry j

Yes I believe I do remember seeing it.

A new o-ring/gasket will solve the problem. Get one from your local GM parts dealer.
I think it was under $3 ?

(It would be a good time to flush things out good for those who do not want to mess with the Dex., although when watched closely it will probably be just fine)

Make sure it is seated properly in the groove, before you tighten it down.
You will have to remove the throttle cable bracket to get the thermostat out. (PITA)
That is one good thing that the TB spacer did. It allows for thermostat removal