Anyone had any expeirience towing with a 4.6L and 3:31 rear end. I mean some serious weight. Not some boat that has no wind drag or light utility trailer. What kind of stress with this rear end am i putting on my tranny. My trailer weight is about 4000# loaded. I cooked one torque converter already. I attribute that to towing without an aux. cooler though. I had one installed before it touched the travel trailer again. It was fixed under warranty at a cost of around 2 grand. OUCH! that would hurt my wallet if i had to pay for it. I intend on having tranny serviced now every 10-15K but i cant figure out what is best method of service. Flushing on a machine or dropping pan and changing filter? Any experts in here i sure would appreciate some advice. The method of tranny service is just because i get conflicting ideas about which method is best.

Dave
2000 F-150XL Supercab 4X4 4.6L 3:31 rear end K@N filter and cat back exhaust ( and no door crack which i cant figure out either lol)

 

Dave,
Trans cooler a must! See my Trans Cooler post.

Also, I highly reccomend a synthetic. For the Dexron/Mercon trans fluid in my '97, I'm using LE Inc. 1107 . As with any synthetic, it's spendy, but so far well worth it...The trans runs like it did, when I bought it!

Once a year (~12-15k miles) I have the trans flushed at Jiffy Lube. Every other year, I have the filter changed at a reputable shop.

let me know if you have any further querstions,
Tony

 

A possible reason for cooking the torque convertor is where the throttle position needed to maintain speed was also one which did not allow the torque convertor to stay locked. Lockup is a function of torque/speed/throttle position -- gleaned from the performance map in the ECM.

For example: If you were towing or ascending a grade (in any gear) AND the torque convertor did not lock, the effect of the torque converter doing it's job of fluid-coupling would generate significant heat.

Heat generation to the point of blueing the convertor has been reported.

 

So Y2K, what is the solution to your hypothesis concerning the torque converter. I always tow with the O/D locked out. The tranny was rebuilt with a mechanical diode instead of a roller

clutch

, a newer overdrive billet servo with better holding force,and a heavier duty torque converter. I was told these are all the updates for Ford reccommended to the tranny shop. Im not a gearhead. Im just copying these parts down. I dern sure dont know what they perform in the tranny.

 

What is "blueing" of the torque converter?

 

Solution to hypothesis is one or more of the following:

a) watch your tach to be sure that the torque converter is locked up

b) change primary drive ratio to 3.55 or shorter to allow engine to spin faster at less throttle position

c) 'chip it' with a custom program that will ensure torque converter lock-up

Blueing -- overheating to the point of metal discoloration.

 

Y2K,
Will synthetics help to prevent the "blueing of the converter. Unfortunatley i do not have a tach. This is an XL work series truck. My wallet will not allow for a gear change either lol. 4x4 has to change both diffs, right?

 

I don't believe there is any way for the transmission and torque converter to survive n this application. I thnk if you look at the tow ratings for this truck you are WAY overloaded.

If you don't change both front and rear gears you will just keep cooking the transmission and torque converter.

A few REALLY BIG coolers might delay the failure for a while, but it's still going to fail.

Mark

 

I think it would be a good idea to install a tranny temp guage. It will help you see if the tranny is over heating or not. Cost is about $50 and should take only a few hours to install.

 

Mark Kovalsky,
I am NOT, REPEAT NOT WAY OVERLOADING THIS TRUCK. AS per the tow rating for a 2000 F-150 Supercab 4.6L V-8 4X4 with automatic tranny and a 3:31 is 5600#. My UVW of the trailer is 3100# per the number inside the cabinet door. Being conservative i say i put 1000#of weight in the tralier, total 4100#. Curb weight of the truck is 4600#. Being conservative again Im adding another 1000# in occupants and payload bringing total of truck weight to 5600# Now add truck weight and trailer weight equals 9700# and thats being conservative. Now per my MANUAL my GCVWR is 10,500. Now i know i am under that GCVWR. Before you flame someone about being overweight i suggest you check your ratings.

 

Geez.. where is that tention coming from?

 

Stickers and guesstimating can be misleading.
Why not put the rig on some scales and put the weight issue to bed altogether?

 

Raoul,
Im gonna do just that before my next destination. Gonna hit Flying J's scales. Dont know if they have any but most do ... i think.

LOL XLT,
Just done a lot of research regarding the weights to insure im within a margin of safety for this truck. Even if i took the GVW of both vehicles , 4400# TT 6250# Truck. My GCVW is 10500 . I exceed that by 150#. I know im not loaded that heavy. I dont think 2 adults ,1 4 year old , 3 bikes and a Power wheels, 1 portable grill and camp stove adds up to 1600 # which is what i need to even get close to the GVW of the truck. I just thought that particular guy doesnt have his weights in line at all with regards to the tow rating of my truck. Hell you can get the ratings for this truck right on this website.

 

There's nothing inherently wrong about 3.31.

Chevy uses 3.42 for the applications where Ford uses 3.55.

Do the math, and you'll find that the differences between the ratios amount to decimal-dust.

Just a few years ago, tire sizes were 235/70R15 -- where a 3.42 (Chev) or 3.31 was quite nice, thank you.

Moving up to yard-wide tires changed things a bit -- and/but the 2.8+ ratio first gear on the 70W tranny works pretty well -- especially since the direct-drive RPM at 55 is pretty squarely in the center of the torque band (not by accident).

I believe you'd really need to be doing something obviously wrong to toast a tranny (or turn a TC blue) -- unless you're brain-dead.

Synthetics merely handle the temperature better than dino-oils.

 

My truck has a 4.6 with 3.55 gears, but I added 32" tall tires. This makes my effective gear ratio 3.27 as compared to stock height tires. I think it is about perfect for interstate towing in third gear (O.D. off) on level ground. I'm right about 3000 rpm at 70 mph. I will loose some speed on some anything more that small hills, but I pull lots of weight (heavy cars and a soild steel deck 18" car trailer). Cars on a open trailer are about all I pull. A camper or enclosed car trailer of equivelent weight would be real burden on the truck. My truck with trailer gets around town ok, but this would not be the hot set-up if I lived in a hilly area. If I lived in the hills, I don't think a set of steep gears alone would cut it. I'd get a truck with a 5.4.

If you don't have the tow package, a trans cooler is great addition to preserve you trans.