Help! 07 Yukon died on side of road!

[Ming15237]

I was towing a 6000 travel trailer and the transmission was getting pretty hot, around 215 degrees. It was a hot day so I decided to pull over and check things out.

When I pulled up to the stop light it just died. It turns over fine but won't start. Every once and awhile I'll hear a fire but it feels as if maybe there's a fuel system problem. Maybe an overheated fuel pump?

I got it towed to a dealer and they will take a look in the morning. I'm hoping someone here has any experience with this one?

Sigh... stuck hours from home on memorial day weekend. Lovely!

As a little frame of reference I am an ASE certified master tech. Given that I do not see what truck you have I would assume that it's a 07 or later given that the dash is telling your transmission fluid temps. Your transmission fluid temps are NOT out of line for a vehicle towing a heavy load. In my opinion the transmission coolers on these vehicles are quite adequate. As an aside I placed an additional transmission cooler on a 2010 Yukon Dinali utilizing the factory Kohler and the additional cooler in the transmission fluid temperatures went down less than 5°. That imho is NOT an indication that the factory cooler is insufficient. The amount of work the transmission is doing is going to creat heat, there is no way around that, thus these vehicles use synthetic transmission fluid which contends with this heat without breaking down like conventional fluid tends too. Now to your problem, I think someone already stated that you likely have a fuel supply issue, this too me makes a lot of sense. Working a vehicle like this will cause under hood temps to soar, thus vaporizing the fuel in the lines. This issue is exacerbated by fuel with a high ethanol content. Try the fuel line wrap, and see if this addresses your issue.

 

[Kenny D]

I had a 93 S10 that was so worn out that it had 0-5psi oil pressure at idle once warm. I used Lucas at each oil change and it worked for that too. Kept my pressure to 20 at idle from then on.

 

[kbuskill]

We don't know which engine he has so the theory of variable valve timing may not apply.

My 2008 Suburban LTZ with the LMG 5.3L doesn't have VVT. I don't believe VVT was available until 2010 on the 5.3L.

 

[mixup52]

That is true. OP what model is your Yukon? If its a Denali then it has the VVT with a 6.2. That's what engine I have.

 

[Paul Brambilla]

That is true. OP what model is your Yukon? If its a Denali then it has the VVT with a 6.2. That's what engine I have.

Yep. 07 Denali 6.2. just a quick update. Not only did I make it over the pass, I did so with ease. The trans temps were rock solid at around 160 the entire time! It maxed out at 170 just as I crested.

Why so much better this time? It seems the combination of tow haul mode plus manually selecting my gears was the sweet spot for me.

All that said, I still have the issue with rough idle and potential stalls after pulling off the highway. I did have to do the two pedal dance a few times.

As of this point, I'm less concerned about transmission temps than I am about solving the stall issue. I might give that Lucas treatment a try next.

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[Paul Brambilla]

Here is what I have been using and it has made a big difference.

I used to get the p0011 code, associated with this issue. I though why not give it a try. I have used this as directed and have not had any issues since.

https://lucasoil.com/products/engine-oil-additives/pure-synthetic-oil-stabilizer

I use the synthetic cause obviously I use synthetic oil. 4 qts or mobile 1 and 1 qt of Lucasoil.

In the past year, I have not had any issues and my CEL turned off due to the p0011 code (camshaft intake position).

Hope this helps.

The other option is to have your motor rebuilt, but I'm not ready for that.

Do you think I need an entire quart of the Lucas of can I just add a small bottle without draining any oil? I just replaced the oil a few weeks ago.

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[iamdub]

Why so much better this time? It seems the combination of tow haul mode plus manually selecting my gears was the sweet spot for me.

So, you were originally towing that 6,000-lb trailer NOT in tow/haul mode? That poor transmission...

 

[Paul Brambilla]

So, you were originally towing that 6,000-lb trailer NOT in tow/haul mode? That poor transmission...

I was, but I was in drive, not manually selecting gears. For me, that just wasn't good enough.

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[iamdub]

Staying out of overdrive when towing is far better than manually shifting. One of the features of tow/haul mode is delayed shifts, so that part is pretty well covered. It's cruising at speed in OD with the weight that causes the extra strain and heat.

 

[Paul Brambilla]

Staying out of overdrive when towing is far better than manually shifting. One of the features of tow/haul mode is delayed shifts, so that part is pretty well covered. It's cruising at speed in OD with the weight that causes the extra strain and heat.

Overdrive is off in either case so long as tow haul is turned on right? In my case tow haul in regular drive was causing issues. I was having trouble getting it to switch into 4th gear so my rpms were near 5000. Is that normal? Tow haul + M was working fantastic. At about 3k rpms I'd simply switch up to 4th and the temp never rose above 170. I was able to cruise up the mountain at about 55 miles per hour holding RPMs at about 2500. I never attempted to switch into 5th while climbing.

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