Transmission temp

[guumbah]

Is there a warning light for the transmission temp?

My truck is acting a little weird whenever the temp approaches 90 degrees outside. The truck takes a little longer to shift to 2nd, and the noise of revving the engine seems higher in pitch, but only when in gear and starting up from a stop. Revving while in Park sounds normal. Literally, one degree ambient will make the difference. 84 and I'm fine, 85 and it will do it. One other thing, it also seems to act normal if I punch it, almost as if the 1500-2000 rpm range I hit when slowly accelerating causes it, but not the higher revs of a fast takeoff. I'm going to change the fluid most likely anyway, but I was just worried that there would be no warning if this thing was really overheating. One more thing of note, I DO have the transmission cooler option. I just added a billet grill and chrome bowtie, so I had the front off, and I inspected the lines, and the little radiator, and everything looks fine (no leaks. damaged fins, or anything).

[Slowprocess]

Originally Posted by guumbah

Is there a warning light for the transmission temp?

My truck is acting a little weird whenever the temp approaches 90 degrees outside. The truck takes a little longer to shift to 2nd, and the noise of revving the engine seems higher in pitch, but only when in gear and starting up from a stop. Revving while in Park sounds normal. Literally, one degree ambient will make the difference. 84 and I'm fine, 85 and it will do it. One other thing, it also seems to act normal if I punch it, almost as if the 1500-2000 rpm range I hit when slowly accelerating causes it, but not the higher revs of a fast takeoff. I'm going to change the fluid most likely anyway, but I was just worried that there would be no warning if this thing was really overheating. One more thing of note, I DO have the transmission cooler option. I just added a billet grill and chrome bowtie, so I had the front off, and I inspected the lines, and the little radiator, and everything looks fine (no leaks. damaged fins, or anything).

No light to my knowledge and I ran my old tranny up extremely high a few times at the track. An aftermarket tranny temp gauge pays for itself in transmission repairs, IMO. They're inexpensive and easy to install. With outside temps that reach that high, you might want to consider an aftermarket cooler as well. These trannies are weak as hell.....even the built ones.

[jethro_3]

Do you haul things in your truck? If yoiu do get a Aeroforce Interceptor gauge. It reads 28 items directly from the PCM. YOu can watch the engine temp, trans temp, intake temp, knock retard,....... Your gauges are really appx not real #'s. Get the gauge and if you have the small console above the rearview mirror get the gauge holder from socaldeisel.com to hold the gauge up above.

This will give you true acurate information without cutting and modifying. Plus if something is wrong you can logg information also.

PM me if you have more questions....

[MT-2500]

Originally Posted by guumbah

Is there a warning light for the transmission temp?

My truck is acting a little weird whenever the temp approaches 90 degrees outside. The truck takes a little longer to shift to 2nd, and the noise of revving the engine seems higher in pitch, but only when in gear and starting up from a stop. Revving while in Park sounds normal. Literally, one degree ambient will make the difference. 84 and I'm fine, 85 and it will do it. One other thing, it also seems to act normal if I punch it, almost as if the 1500-2000 rpm range I hit when slowly accelerating causes it, but not the higher revs of a fast takeoff. I'm going to change the fluid most likely anyway, but I was just worried that there would be no warning if this thing was really overheating. One more thing of note, I DO have the transmission cooler option. I just added a billet grill and chrome bowtie, so I had the front off, and I inspected the lines, and the little radiator, and everything looks fine (no leaks. damaged fins, or anything).

Engine tempture has a lot of affect on transmission tempt.
Anything out of normal on engine running tempt?
A good trans/engine capable scanner will read out transmission and engine running temptures.
MT
MT

[Slowprocess]

I use my palm and ls1m to read and log EVERYTHING going on in the truck. I can then convert them to autotap files for my tuner. Good thing to have.

[guumbah]

Originally Posted by MT-2500

Engine tempture has a lot of affect on transmission tempt.
Anything out of normal on engine running tempt?
A good trans/engine capable scanner will read out transmission and engine running temptures.
MT
MT

Nope, engine temp goes up to the exact same spot on the dial once warmed up.

[guumbah]

Originally Posted by jethro_3

Do you haul things in your truck? If yoiu do get a Aeroforce Interceptor gauge. It reads 28 items directly from the PCM. YOu can watch the engine temp, trans temp, intake temp, knock retard,....... Your gauges are really appx not real #'s. Get the gauge and if you have the small console above the rearview mirror get the gauge holder from socaldeisel.com to hold the gauge up above.

This will give you true acurate information without cutting and modifying. Plus if something is wrong you can logg information also.

PM me if you have more questions....

Mostly no hauling, just small loads of wood and home improvement stuff every other week or so, all local. And the occasional moving help (being the only one of my friends with a truck). But I looked at that gauge when you (I think it was you) posted a link in another thread. Very nice.

[guumbah]

Originally Posted by Slowprocess

No light to my knowledge and I ran my old tranny up extremely high a few times at the track. An aftermarket tranny temp gauge pays for itself in transmission repairs, IMO. They're inexpensive and easy to install. With outside temps that reach that high, you might want to consider an aftermarket cooler as well. These trannies are weak as hell.....even the built ones.

Will I need a sensor? I heard if you install the Caddy gauges the trans temp gauge will work already, is that sensor usable aftermarket too?

For the cooler, can I use the existing lines and just replace the radiator part.

[guumbah]

Almost embarassed to say what fixed this.

Like a lemming, I read about the 'free' mods and went ahead and descreened my MAF. In my case, at least, bad idea. It ended up throwing off the computer, making it shift at different points, and run really reeeeaalyy lean. First clue was hooking it up to my buddy's scanner-equipped laptop. All t1he temps were fine, no codes, etc. Second clue was suddenly getting 200 extra miles out of a tank of gas. Now I gotta check the plugs.... At least all the extra gas paid for the new MAF on ebay (I destroyed the screen getting it out...) Put the new MAF in a couple days ago, and the high revs have gone away. It's been just as hot as when this first started happening. Truck runs smoothe again!

[jeep_cj4x4]

Thats good to know. Glad you got it fixed. Now, I have a question.... How do you hook up a laptop to the truck? Is there just a special cable/program to buy? Is it expensive or fairly cheap? Are you just able to monitor engine conditions or can you program the truck and is it worth it?

[MT-2500]

Originally Posted by jeep_cj4x4

Thats good to know. Glad you got it fixed. Now, I have a question.... How do you hook up a laptop to the truck? Is there just a special cable/program to buy? Is it expensive or fairly cheap? Are you just able to monitor engine conditions or can you program the truck and is it worth it?

This link here shows one.
http://www.troublecodes.net/articles/Carcoderview.shtml
But to reprogram the pcm you need a special program and equipment.
This one is just a laptop or pc based scanner program.
A lot of tech/mechanics are going to a laptop scanner setup.
They work good for road testing and storing data and reading later..
MT

[guumbah]

I don't know exactly which one my buddy has, but it is similar to that one. Able to read a lot of detailed stuff, but definitely read-only.

[MT-2500]

Originally Posted by guumbah

Almost embarassed to say what fixed this.

Like a lemming, I read about the 'free' mods and went ahead and descreened my MAF. In my case, at least, bad idea. It ended up throwing off the computer, making it shift at different points, and run really reeeeaalyy lean. First clue was hooking it up to my buddy's scanner-equipped laptop. All t1he temps were fine, no codes, etc. Second clue was suddenly getting 200 extra miles out of a tank of gas. Now I gotta check the plugs.... At least all the extra gas paid for the new MAF on ebay (I destroyed the screen getting it out...) Put the new MAF in a couple days ago, and the high revs have gone away. It's been just as hot as when this first started happening. Truck runs smoothe again!

Thanks for letting us know the fix.
Kinda interesting about the screen.
Different setups act different to mods.
Here is a quick test on MAF sensor if it gives you any more problems or things to watch on it.
And always make sure your baro readings match your altitude.


BAROMETRIC PRESSURE REFERENCE CHART
Barometric Barometric BARO/MAP Altitude Above
Pressure Pressure PID Sea Level
(in. Hg.) (kPa) (Hz) (ft)
3.5 11.8 89.3
5 16.9 92.8
10 33.8 104.6
15 50.7 117.0 14,000
20 67.5 129.6 10,000
21 70.9 132.5 9,000
22 74.3 135.4 8,000
23 77.7 I 138.3 7,000
24 81.1 141.1 6,000
25 84.4 144.0 5,000
26 87.8 146.9 4,000
27 91.2 149.8 3,000
28 94.6 152.8 2,000
29 97.9 155.8 1,000
30 101.3 158.9 0 (sea level




On a fully warmed up engine, look at Long Term Fuel Trim at idle, in Neutral, A/C off, (LONGFT1 and/or LONGFT2 PIDs). If it is more negative than -12%, the fuel system has learned lean corrections which may be due to the MAF sensor over-estimating air flow at idle. Note that both Banks 1 and 2 will exhibit negative corrections for 2-bank system. If only one bank of a 2-bank system has negative corrections, the MAP sensor is probably not contaminated..

3. On a fully warmed up engine, look at MAF voltage at idle, in
Neutral, A/C off (MAF V PID). If it's 30% greater than the nominal MAF V voltage listed in the Powertrain Control/Emissions Diagnosis (PC/ED) Diagnostic Value Reference Charts for your vehicle, or greater than 1.1 volts as a rough guide, the MAF sensor is
over-estimating air flow at idle.

4

If at least two of the previous three steps are true, proceed to disconnect the MAF sensor connector. This puts the vehicle in to Failure Mode and Effects Management (FMEM). In FMEM mode, airflow is inferred by using rpm and throttle