I've got an 02 F350 7.3 (see sig), just picked up our new Carbon 337 toyhauler in Reno yesterday and pulled it up Hwy 80 over the summit, back to California.

I was monitoring the tranny temp using Torque Pro (PID 221674). It pulled most of the hills in 3rd, only shifted to 2nd twice for short stretches. The highest temp I saw while on the highway was 207, most of the time it was around 200-204 on the harder pulls. A touch high.

The really scary part was when I was almost home, the road up to our property is narrow, twisty and steep, a slow crawl with the hauler in tow, and on the last little bit the temp hit 245. This part of the road is less than 2/10 mile long and the temp only got that high for the last minute or so, but I know it's still not good.

And this was with the hauler empty (no fresh water, dirt bike or gear), only the fuel station was full.

I know I have a problem, looking at trans cooler upgrades (replace with 6.0L stock cooler or add aftermarket like the Derale Series 8000), and maybe a larger capacity pan (Mag-Hytec?).

My question is, will those make enough difference to get me down to acceptable temps and allow me to tow with this truck for a while?

I know I'm overloaded, and do plan to upgrade my TV, but I'd sure like to be able to pull it with the 02 for at least a little while.

 

I know when I purchased my 2005 f350 {6.crap} salesmen recommended a upgraded for a snowplow which will give me a different package for trani I don't remember completely but more oil capacity and a maybe a cooler for trani. One thing for sure the cat converter or muffler is so close to trani doesn't help things either

 

I don't think you have a problem. You come in off the road and then drop down to a crawl. Torque converter unlocked and air flow across the tranny cooler falls way off. I have a similar situation with a very steep hill and then have to back my fiver up a very steep driveway, so I have seen those temps more than one time.

A 6.0 cooler helps a bunch and dropping down into 4-lo also helps. I would definitely suggest trying the 6.0 cooler before making a decision for a new truck. The cooler is hugely cheaper!

Steve

 

Mark K will tell you there's nothing wrong with any of the temps you indicated, they're not alarming. Listen to him.

 

Not even a touch high. That's absolutely normal.

It's not the best, but it isn't bad. The trans can go up to 250°F for not more than a half hour at a time with no damage.

I don't think you have a problem, but the temps can be improved.

Replace the stock aux cooler with one from a 6.0L F-Series. A bigger pan only makes the underside of your truck look nice, it doesn't do anything else for the trans.

Since the temps right now are acceptable, upgrading the cooler will only make them better.

Only in the salesman's mind. In real life there was one transmission and one transmission cooling package. There were no unique transmission or transmission cooling parts with a snowplow package.

And that's the biggest reason a bigger pan won't help cool the trans.

I completely agree with the 4 low and trying a better cooler before replacing the truck.

 

More fluid = cooler temps

 

wow, so glad I came here with my questions, thanks guys! Mark, I really appreciate your expertise and detailed answers. I've been reading elsewhere that anything over 200 is cause for concern, and getting close to 250 for any length of time is asking for it, I'm very glad that's not the case!

I'm gonna get the 6.0 cooler and try 4-low next time up my hill. Hope this isn't a stupid question, but do I actually need to engage the front hubs when doing this, or does it not matter?

 

Not if you have auto hubs, be careful 4 low usually produces more heat

 

Actually unless I am in 4 lo, I will have transmission blowing out my seal every time.

 

How much weight were you pulling?

 

About 10,000 pounds

 

I've studied thermodynamics, and I was a transmission cooling engineer, yet I still don't understand this. Please explain how more fluid equals cooler temps.

 

Mark is THE MAN on any auto trans questions here.
For the low speed crawling/maneuvering with the TH you don't have to lock your hubs, in fact if you can run in LOW range with the hubs unlocked you will avoid any binding if you are getting good traction.

 

Using LOW range works well for me to keep the trans from getting too hot when backing our 11,000lb TT into camp sites and up our inclined driveway at home. The 4R100 sometimes suffers a leaking front seal if it is hot and backed uphill slowly with a heavy trailer from the extra heat generated and the limited air flow over the cooler, using LOW range actually helps to keep it from getting as hot.

 

I've heard that a few times now, local mechanic told me that Reverse is the weakest part of these trannies, and using 4 low when backing up a big fiver is a good habit to be in!