Good morning all, been lurking for a while, but didn’t seem to find an answer so I thought I’d post.

2002 F350 4x4 CCLB V10 3.73s w/ 108k miles

I’ve had the truck for about a year but only recently started towing with it. First trip was probably 7500# for around 900 miles. I didn’t have a gauge so I don’t know the temps, but it puked fluid after 850 miles (north to south) so I pulled over and got towed the rest of the way home.

I bought an SG2 to keep an eye on trans temps while towing the TT@~6800#. In Florida heat on some minor grades I got it up to 232 so I pulled over and let it cool.

After that I bought a rockauto 6.0 cooler and it helped, but I was still running around 200 at 65mph on flat road. Any downshifting and it climbs pretty quick but goes back down after I level off.

Last trip was to the mountains in NC and I pushed it to the limit and got the temps up to 235 and it puked twice so I pulled over. I even tried going up the 7% grade in 4Lo unlocked, but it would go from 200 to 235 in a quarter mile so I tucked tail and let my BIL tow it up the mountain in his ‘19 Cummins. (my ego was too bruised to care by that point).

Last night I did the Mark Kovalsky fluid exchange. The old fluid was still fairly red, had a little bit of a funky smell but there wasn’t any gunk in the pan and about 1/16” sludge on the magnet.

I drained 18 quarts, but put 17 back in because I noticed it was overfilled after I did the 6.0 cooler install. It’s still overserviced a little, but I have a question about the dipstick. Well, I have a ton of questions, but this one is the first.

Mark said that all the truck dipsticks were the same, but mine has the little loop on the end, not the white plastic piece that I’ve seen in some pics. It looks original and it’s a Ford dipstick and the part number looked right, but how would I know if it’s correct? It’s reading over-serviced by about an inch on the dipstick but I’m not sure how much that is in reality.

Also, if it matters, here are the parameters from my Scangauge.

IAT- 80
TFT- 190
LPC- 5.0
SLP-0.99
GR- 0.70
WT- 184
MPH- 55 (cruise set, roads flat)

That 190 seems high for fresh synthetic with a 6.0 cooler, no obstructions, and proper flow, i.e. 1 qt/15 seconds (verified last night). Also, no fluid was coming out of the transmission so I assume the bypass is still good.

It climbed steadily at a rate of 2 degrees per mile, up until I got to 185. It was still climbing but I didn’t want to drive to California to see where it would plateau so I ran it from 185 up to 190 with OD off then turned OD back on and it slowly dropped back down to 186. All said, it was about 20 miles of driving at a very steady 55, no traffic, no red lights around 9:30pm.

Also, one last random tidbit, how accurate is the trans temp sensor at low temps? The truck hasn’t ran for almost 12 hours, it’s 86 outside, but my trans temp says 121? There’s no way, right? Anybody know if the temp indication is bad? I know it pukes at 233 indicated and that’s fairly repeatable.

I saw the fan clutch post too, but I don’t really know what I’m looking for. The fan always runs. When the truck is off and cold, I can’t turn the fan more than one blade at a time.

Any help is greatly appreciated. If this is normal and it’s fine, then I’m fine too. But if something is wrong then I want to get it under control. I’m just bummed because everybody says that the 6.0 cooler runs at 140-170 towing 60,000# in Death Valley and produces ice cubes when driving empty.

Sorry for the long first post, but I wanted to be thorough. If anybody has any advice then I’d love to hear it. I think I need to drain a little more, but not knowing if I have the right dipstick has me hesitant. If I do drain, should I just hook my tube and bucket back up and drain another quart or two? Or is there a better way?

thanks in advance!

 

Among other troubleshooting methods, you can always aim an IR thermometer at your trans. pan and compare that reading to your gauge. I would think it should be within 10 degrees F. Is your torque converter locking as it should, in both 3rd and 4th?

 

4th- Yes. At least I assume so since my slip ratio is 0.99.
3rd- I’m not real sure. I didn’t notice but if I run out today then I’ll check.

The IR thermometer is a good idea, but I don’t own one. I suppose I’ll need to pick one up to check that.

 

I recommend a rebuild kit for the bypass. It's about $25 from Summit Racing. It's easy to install and might fix your cooling issue. if it doesn't fix it you most likely have a partially plugged cooler or a damaged cooler line.

 

Thanks for the reply, Mark. Definitely not questioning you, but that’s taking into consideration that the cooler is new, the bypass wasn’t leaking during the flow test, and I had a satisfactory 1 GPM flow? Do you think it’s probable that maybe the new cooler collected some debris after install? It only has about 2000 miles since install but I didn’t change the fluid until now.

Also, for my own edification, was there a clue in my post that makes you lean towards faulty bypass?

I looked for the rebuild kit from Summit but the only thing I found was the delete kit, and I’ve already subscribed to your train of thought on that front. Is the Sonnax kit on Amazon acceptable? I can get that on order ASAP.

 

I have a similar truck, 1999 F350 4x4 DRW V10 3.73 w/165k, 10k on a rebuilt engine. I tow a 5th wheel trailer in the mountains of Oregon. I installed the 6.0 cooler and an dual electric fan set in front of the trans cooler. It is a good system, but definately not a 100% fix for my towing situation. I generally run it up to 220 and look for the next pull out in a big grade. I open the hood and let the fans cool it down for 5-10 minutes and can climb another couple of miles before pulling out again. Repeat as necessary. This setup has been running fine on level ground. Maybe 185-195 degrees on a 90 degree day.

I'm curious where the trans fluid is "puking" from. Is the fluid boiling? I've not had this problem.

I would definately change the sending unit if you haven't already, the ambient temperiture experiment you did sounds like there is a problem.

 

Also, are you running the 6.0 cooler in series with the radiator oil cooler (OTW, Oil to Water, I think it is refered to) you definately want to do that. If you search the v10 forum you can find a thread on my installation.

 

Yep, I pulled the stock cooler and installed the 6.0 in its place. The fluid comes out of the front pump seal (at least that’s what I’d call it) and drips down onto the exhaust pipe. Makes an awful lot of smoke and looks terrible. I panicked the first time I saw it and had my
FIL come get me in his F450 and gooseneck to tow me home. I’ve since learned that it’s somewhat common. It’s only happened when it’s really hot and I’m towing heavy (to me). My biggest hang up is that I see F150s/1500s towing similar trailers. My truck
seems like a heck of a lot more truck.

As far as the temp sender, I want to check the operating temp with a known good source prior to replacing. I really don’t care if the low side is off, but I definitely want it reading accurate at operating temps. But, if it’s reading 35* high then that means its running at 150* but it’s puking at only 200* and that doesn’t seem right either. I know they’re more accurate, but didn’t know if they can become unreliable at lower temps.

 

FWIW, I can hit 215 on flat ground with my 6800# TT. My 2 year old copilot used his big toe from his car seat to turn off overdrive last outing and it climbed past 215 on flat interstate. I noticed the temp climbing and it was crossing overpasses with much more ease than normal... then looked down and saw the OD was off.

billybob, which dipstick do you have? The white plastic one or the metal one with a loop?

How much of an impact will overservicing have on temp? I know it’s not good, but is it bad enough to overheat it?

 

It was just a guess. They do fail, and the rebuild kit is cheap enough and easy enough to install.The Sonnex kit is fine.


That sure doesn't seem right. With the 6.0L cooler, it should do a lot better than that.

Quote:

Originally Posted by billybobofkf

I'm curious where the trans fluid is "puking" from. Is the fluid boiling? I've not had this problem.

The trans would be destroyed by heat before the fluid boils.

The torque converter hub seal is the cause of the leak. When the seal gets hot it softens and leaks. Once it cools it usually works fine again. There is a better seal available in the aftermarket. It's made from a material called Viton.

What is overservicing?

 

Sorry, “over-filling“. I’m a helicopter mechanic by trade so some of that aviation lingo slips out without noticing.

 

As a quick experiment, I used my multimeter with the temperature wire and I duct taped it to the pan. When I cranked the truck, the ambient temp was 86, the pan temp was 88 on the meter, and 120 on the Scangauge. After about 10 minutes, the multimeter read 110 and the Scangauge read 137. The 32 degree delta only narrowed to a 27 degree delta, but the gap did shrink. I want to try again after I get it hot, but duty called and I had to go in. The Scangauge is definitely wrong at low temp, but I’m not sure how far off it is at operating temp. Yet.

Sonnax kit is ordered but won’t be here for a week.

 

The pan is going to be cooler than the Scangauge reading. The Scangauge is reading in a spot that is hotter than the pan in almost all conditions, except when the truck has been sitting for a long time.

 

Ok, thanks Mark. Is there a more reliable way to confirm the temp? I know it wasn’t 120 prior to starting it. But, it did take about 5 minutes before it started climbing up from 120. Maybe it’s just incorrect when it’s off/first started? Seems strange.

Any thoughts on fluid level/dipstick? I’m thinking I’ll drain a quart and check again.

 

Well, I drained 2 quarts then drove it to get it hot; then checked and there was nothing on the dipstick. I added one quart, now it’s way over again. I waited a minute or two to let the fluid drain from the tube. Either I’m reading the dipstick wrong or something goofy is going on. Is it really that sensitive?

During the drive I confirmed the SLP ratio is still 0.99 in 3rd. I think that means the TC is locked. After about 10 miles driving in 3rd, then another mile or two driving pretty hard (pedal to the floor 50 to 70mph runs about 3 or 4 times), the temp got to 192. When I got back to the house I checked the pan temp at various points and the highest was 148. I know it will measure cooler, but does that sound about right? I also checked the cooler return line and it was 128 at the fitting. My trans cooler hoses behind the bumper are warm, but not hot. Does any of this sound indicative of simply a cooling problem or impending trans failure?

The bypass valve kit is on order, but I may see if Napa has the whole thing for a couple bucks more so I can know sooner than later.

I’m used to being wrong, but the fluid level does not seem to be the culprit if I’m getting nearly identical results both over- and under-filled. I haven’t ruled out the fan clutch, but I know that thing is definitely moving some air.

Again, sorry for the novella. I tend to think more info is better but I realize it can also be overwhelming to the reader.