42RLE clicking sound on shifting into gear when transmission is hot

[TJMexico]

I just did another long slog up the big mountain and have a few questions about best practices with this transmission (42RLE paired with a 4.0l 6cyl on a 2005 X model). But I'll save those for another thread. Like my analogy of changing from horses to mules, I'm still learning how to best use this drive train and am adjusting my driving style to fit in with how it best functions. This is my first automatic 4wd in almost 40 years, and my last one was a GMC pickup with a 350 back in the early 80s. Everything since then has been manual shift (horses to mules).

My question now has to do with a recurring issue.

I posted back on August 15 (here...) about a trip that I am now making regularly. I posted this elevation/distance graphic to explain where my issue was:

That climb from the 40km to the 50km mark is brutal. The road is steep, very curvy and littered with rocks and washouts/gullies. I have been doing in mostly in 4hi and drive with O/D turned off, shifting down to 2nd or 1st gear or even 4lo when it feels like the tranny is straining.

First time I did it, the tranny really overheated and when we stopped at the top for a rest and a visit in a village, the transmission would make a loud but short clicking sound (maybe a little less than one second) when I put it into gear (forward or reverse) right after we had stopped. After sitting for about half and hour and letting the drive-train cool down a bit, we got back on the road and it didn't do that any more. Initially scared the hell out of me!

Previous trip I didn't notice that happening.

This past trip, it happened again, but the drive-train/tranny did not heat up nearly as much. The sound was not nearly as loud as the first time and maybe even shorter, and after sitting for a few minutes and cooling down it went away again.

So, I am wondering:

• if anyone else has had this happen.
• if it is somewhat "normal."
• if it might be indicative of bigger problems coming.
• if there is anything I need to have checked to avoid future failure.

(I really want a temp gauge on the transmission, but the company in the U.S. that makes the pan does not ship to Mexico, and the best I can do here in the shop - at least as far as I have found up to now - is a bronze solder.)

 

[Chris]

I just did another long slog up the big mountain and have a few questions about best practices with this transmission (42RLE paired with a 4.0l 6cyl on a 2005 X model). But I'll save those for another thread. Like my analogy of changing from horses to mules, I'm still learning how to best use this drive train and am adjusting my driving style to fit in with how it best functions. This is my first automatic 4wd in almost 40 years, and my last one was a GMC pickup with a 350 back in the early 80s. Everything since then has been manual shift (horses to mules).

My question now has to do with a recurring issue.

I posted back on August 15 (here...) about a trip that I am now making regularly. I posted this elevation/distance graphic to explain where my issue was:

View attachment 655200
That climb from the 40km to the 50km mark is brutal. The road is steep, very curvy and littered with rocks and washouts/gullies. I have been doing in mostly in 4hi and drive with O/D turned off, shifting down to 2nd or 1st gear or even 4lo when it feels like the tranny is straining.

First time I did it, the tranny really overheated and when we stopped at the top for a rest and a visit in a village, the transmission would make a loud but short clicking sound (maybe a little less than one second) when I put it into gear (forward or reverse) right after we had stopped. After sitting for about half and hour and letting the drive-train cool down a bit, we got back on the road and it didn't do that any more. Initially scared the hell out of me!

Previous trip I didn't notice that happening.

This past trip, it happened again, but the drive-train/tranny did not heat up nearly as much. The sound was not nearly as loud as the first time and maybe even shorter, and after sitting for a few minutes and cooling down it went away again.

So, I am wondering:

• if anyone else has had this happen.
• if it is somewhat "normal."
• if it might be indicative of bigger problems coming.
• if there is anything I need to have checked to avoid future failure.

(I really want a temp gauge on the transmission, but the company in the U.S. that makes the pan does not ship to Mexico, and the best I can do here in the shop - at least as far as I have found up to now - is a bronze solder.)

Automatic transmissions are sensitive to heat, and overheating can cause the fluid to break down. If the fluid is too hot, it can lead to delays in engagement or create noises as the components are struggling to function correctly. It’s great that the noise lessened with cooler temperatures, which suggests it’s heat-related. You should absolutely by all means have an aftermarket transmission cooler on there. Heat is the number one killer of automatic transmissions, and the factory cooler simply isn't up to the task.

If you haven’t done so recently, check the condition of your transmission fluid. It should be a bright red color and not smell burnt. Dirty or burned fluid can affect the performance of the transmission and could lead to issues like what you’re experiencing.

While it’s normal to hear some roughness in automatics when moving from park to drive or reverse, consistent clicking sounds might indicate wear in components like the torque converter or the clutches inside the transmission. Keep an eye (or ear) on it, especially if it gets louder or more frequent.

As for a temp gauge, that’s definitely a good tool to have, especially for heavy-duty use. Like I said, heat is the number one killer for automatic transmissions!

Lastly, how many miles are on the transmission?

 

[MikeE024]

(I really want a temp gauge on the transmission, but the company in the U.S. that makes the pan does not ship to Mexico, and the best I can do here in the shop - at least as far as I have found up to now - is a bronze solder.)

Do you have a contact in the US that you can have a pan sent to? (then have your contact ship it to your location)

 

[Ashim]

How fast are you going when driving up this hill? If 15MPH or less I'd be using 4LO.

 

[TJMexico]

Automatic transmissions are sensitive to heat, and overheating can cause the fluid to break down. If the fluid is too hot, it can lead to delays in engagement or create noises as the components are struggling to function correctly. It’s great that the noise lessened with cooler temperatures, which suggests it’s heat-related. You should absolutely by all means have an aftermarket transmission cooler on there. Heat is the number one killer of automatic transmissions, and the factory cooler simply isn't up to the task.

If you haven’t done so recently, check the condition of your transmission fluid. It should be a bright red color and not smell burnt. Dirty or burned fluid can affect the performance of the transmission and could lead to issues like what you’re experiencing.

While it’s normal to hear some roughness in automatics when moving from park to drive or reverse, consistent clicking sounds might indicate wear in components like the torque converter or the clutches inside the transmission. Keep an eye (or ear) on it, especially if it gets louder or more frequent.

As for a temp gauge, that’s definitely a good tool to have, especially for heavy-duty use. Like I said, heat is the number one killer for automatic transmissions!

Lastly, how many miles are on the transmission?

It's the original, I'd assume, so just over 160,000km or just under 100,000 miles.

I do check the fluid regularly, usually at least before or after every long slog. It looks to be in decent shape and does not smell bad.

I had the fluid and filter changed a few weeks ago and the mechanic said it was pretty rough. Since only about half the fluid is swapped out as 4 qts stay in the torque converter, I'm thinking that maybe another change in a few weeks might be a good idea.

 

[Chris]

It's the original, I'd assume, so just over 160,000km or just under 100,000 miles.

I do check the fluid regularly, usually at least before or after every long slog. It looks to be in decent shape and does not smell bad.

I had the fluid and filter changed a few weeks ago and the mechanic said it was pretty rough. Since only about half the fluid is swapped out as 4 qts stay in the torque converter, I'm thinking that maybe another change in a few weeks might be a good idea.

Changing the fluid wouldn't be a bad idea. I'd for sure invest in an aftermarket transmission cooler and temp gauge. Heat kills these things! Under 100k isn't that bad. I'd expect it to least until at least 150k before a rebuild. However, depending on how you drive it and how much heat it sees (towing too) you could easily have a transmission that is starting to go bad around that mileage.

 

[TJMexico]

Changing the fluid wouldn't be a bad idea. I'd for sure invest in an aftermarket transmission cooler and temp gauge. Heat kills these things! Under 100k isn't that bad. I'd expect it to least until at least 150k before a rebuild. However, depending on how you drive it and how much heat it sees (towing too) you could easily have a transmission that is starting to go bad around that mileage.

Yeah, I'm looking at a heavy-duty cooler. The one on it now is definitely smaller than optimum.

 

[TJMexico]

Do you have a contact in the US that you can have a pan sent to? (then have your contact ship it to your location)

I'm considering this. Between shipping and potential tarrifs, it could get expensive, but still cheaper than a new transmission!

 

[TJMexico]

How fast are you going when driving up this hill? If 15MPH or less I'd be using 4LO.

On that stretch up the mountain, Ashim, I am generally pulling less than 25kph, which comes out to 15mph maximum. This is something I was planning to address in another post soon, best practices for this kind of driving. I have heard that 4lo makes the tranny heat up, but in cases like this that does not seem to make sense to me. I'd think that using 4lo in a situation like this would actually take much of the load off of the transmission and keep it cooler.

I do switch back and forth some when I get to really bad spots, and I use 4lo on rough downhill stretches when I don't want to heat up my brakes.

I'll do a post about these issues soon, once this one has run its course, and see what the general consensus is for best practice both up-hill and down-hill.

 

[TJMexico]

Here is another question that probably should have its own post. I hope it does not distract from the main discussion that I started here...

Might it be worth swapping to a 32RH at some point if the I have problems with the 42RLE? I could probably get a decent rebuilt here if I needed to do an major overhaul. I don't know if it would bolt in without major modifications, though.

Is the 32RH tougher than the 42RLE? I know that it's a simpler unit, and it seems that it does not have the electronics that the current one has. Of course, this may give the ECM a splitting headache or a case of psychosis...

Just a brain fart. But back to my original discussion...

 

[Chris]

Here is another question that probably should have its own post. I hope it does not distract from the main discussion that I started here...

Might it be worth swapping to a 32RH at some point if the I have problems with the 42RLE? I could probably get a decent rebuilt here if I needed to do an major overhaul. I don't know if it would bolt in without major modifications, though.

Is the 32RH tougher than the 42RLE? I know that it's a simpler unit, and it seems that it does not have the electronics that the current one has. Of course, this may give the ECM a splitting headache or a case of psychosis...

Just a brain fart. But back to my original discussion...

The 32RH is a better transmission. You’ll find that most around here will agree. It’s tougher, it’s simpler, and many people do the swap. When your 42RLE goes out, that would be something to consider for sure. Only thing to be aware of is you’ll likely have to re-gear since you’ll have 3-speeds as opposed to 4.

 

[TJMexico]

The 32RH is a better transmission. You’ll find that most around here will agree. It’s tougher, it’s simpler, and many people do the swap. When your 42RLE goes out, that would be something to consider for sure. Only thing to be aware of is you’ll likely have to re-gear since you’ll have 3-speeds as opposed to 4.

La Negrita almost never sees pavement. Only time is the occasional run of about a 50 mile into town for mechanic work, and this is only every two or three months. Would I need to re-gear for almost stictly off-road work?

And no trouble with the ECM?

 

[Ashim]

On that stretch up the mountain, Ashim, I am generally pulling less than 25kph, which comes out to 15mph maximum. This is something I was planning to address in another post soon, best practices for this kind of driving. I have heard that 4lo makes the tranny heat up, but in cases like this that does not seem to make sense to me. I'd think that using 4lo in a situation like this would actually take much of the load off of the transmission and keep it cooler.

I do switch back and forth some when I get to really bad spots, and I use 4lo on rough downhill stretches when I don't want to heat up my brakes.

I'll do a post about these issues soon, once this one has run its course, and see what the general consensus is for best practice both up-hill and down-hill.

4LO doesn't cause the transmission to overheat, just the opposite, runs cooler since less load.

 

[Chris]

La Negrita almost never sees pavement. Only time is the occasional run of about a 50 mile into town for mechanic work, and this is only every two or three months. Would I need to re-gear for almost stictly off-road work?

And no trouble with the ECM?

What are your gears at now?

You'll have to get a different ECM most likely. I'm not sure what all the swap involves but there are threads that detail it. The 42RLE is computer controlled, the 32RH is not.

 

[Chris]

4LO doesn't cause the transmission to overheat, just the opposite, runs cooler since less load.

He's in Mexico though and if he's off-roading there in the desert it may get pretty damn hot in the summer, especially with little airflow to the radiator / factory transmission cooler.

 

[TJMexico]

What are your gears at now?

You'll have to get a different ECM most likely. I'm not sure what all the swap involves but there are threads that detail it. The 42RLE is computer controlled, the 32RH is not.

It's stock for a 2005 model X. Not sure, but I'll have to check into that.

Anyway, that's a big maybe and hopefully far down the road. But the input is priceless. Thanks.

 

[TJMexico]

He's in Mexico though and if he's off-roading there in the desert it may get pretty damn hot in the summer, especially with little airflow to the radiator / factory transmission cooler.

I am kind of on the edge between desert and mountains, so summers here low are "pretty damn hot," but I go up into the big mountains, too, where it's cooler. I definitely need to get a bigger cooler. Working on that. We going into winter so no rush, probably.

Got a friend coming down in February. If he brings down a checked bag, maybe he can bring the pan and I'll get the new pan, the temp sensor, the cooler and the fluid change all in one whack.