Torque converter problem?

rjbest · #1 06-18-2008, 09:02 PM

This is an '94, F-150 with a stroked 351 engine to 390cu.
Towing my 5th wheel rv is no problem however when going up a grade, or hill. the engine tends to increase RPM, sometimes by 50 to 300 RPMs depending on the steepness of the grade. I guess my question is, is the engne creating too much torque for the standard torque converter and would it be advisable to have have a "tighter" one put in.

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Matts ford · #2 06-18-2008, 10:46 PM

most likely with the motor you would need a new converter. what numbers is the motor putting out. i would have a rebuilt tranny with a shift kit with a built motor like that.

built54 · #3 06-18-2008, 11:02 PM

yeah something is slipping. how does the fluid look?

Matts ford · #4 06-18-2008, 11:41 PM

hey built54 i saw your supercharged f150 on youtube the other day and that is a badass truck.

rjbest · #5 06-19-2008, 10:23 AM

I don't know for sure about the motor numbers but I suspect it's putting out around 330 hp at the rear wheels and I don't know about torque. It has 3.5 rear end gears. I'm going to have it checked out on a Dyno. Originally, the truck had a 302cu engine with the standard converter for this size engine so I suspect you are correct. My mileage went to hell too, from around 17 with the 302 to 11 with this new engine and still worse towing at around 9mpg but I guess that's the price you pay.

MitchF150 · #6 06-19-2008, 10:42 AM

If your trans has a 'locking' TC, then it's simply 'unlocking' during those times and it's creating a ton of heat on the fluid while doing it!

Mine does it (E4OD) when in 2nd, 3rd and OD if allowed.. For short bursts, it's not a bad thing, but if you are towing a heavy load on a long grade and the TC is 'unlocked'.... You WILL get some serious heat in the fluid...

Mine will shoot up to 210* in a couple of minutes of 'unlocked' condition... Does not matter how large of a trans cooler you have either... It's all being generated in the TC, so this is the temp before it even 'see's' a cooler...

The only gear I have been able to get the TC to lock in is 2nd.. If I see that it's unlocked in 2nd, I press the pedal more and it'll then lock. The only thing that will get the TC to lock in 3rd is MPH, so it needs to get back to a particular speed of around 35 mph before it'll lock, and letting OFF of the pedal some (towing, it's usually in 2nd anyway if only going 35 mph...)

If you don't already have one, a trans temp gauge will tell you a lot of things that's going on with your trans at any particular time...

So far, I've not seen any higher then 210* on mine, but that's only under low speed, unlocked conditions.. Cruising down the road, even in 100* heat, it's normal operating temp is 180* and that's towing or not..

Just my thoughts on it... Mitch

rjbest · #7 06-19-2008, 07:34 PM

You are absolutely 100% correct. I did have the tranny overheat going up a steep grade while towing. So bad, it actually stalled the engine but I was lucky enough to be able to just pull off the road. In about a 1/2 an hour things cooled down enough to where I could get it to crank and start up. We were about 65 miles away from home and it being a Sunday, nowhere could I get it looked at so I drove it all the way home going about 25mph with the flashers banging away.
At the time, I didn't have a tranny cooler in but now I do. What really irks the hell out of me is the Ford owners manual. If you read the specs. a 2x2 F-150 w/302 is rated to haul a 6,000 trailer load. If that isn't a joke, I don't know what is. These semi's will blow you off the road on the Interstates and you won't be doing very good in the mountains either. I wish they would be a little more truthful when they put it in print.

Matts ford · #8 06-19-2008, 09:13 PM

Quote:

Originally Posted by rjbest

At the time, I didn't have a tranny cooler in but now I do. What really irks the hell out of me is the Ford owners manual. If you read the specs. a 2x2 F-150 w/302 is rated to haul a 6,000 trailer load. If that isn't a joke, I don't know what is. These semi's will blow you off the road on the Interstates and you won't be doing very good in the mountains either. I wish they would be a little more truthful when they put it in print.

it just means that it can move the load. they dont say anything about driving down the road at 50-75 mph or higher.

rjbest · #9 06-20-2008, 07:55 PM

Yup....live and learn.

rjbest · #10 06-21-2008, 10:37 AM

You lost me with the "shift kit", please explain this terminology to a rookie mechanic. :-)

Matts ford · #11 06-22-2008, 02:40 PM

a shift kit is an internal tranny mod and you would want one that gives your truck a firm shift because there will be less slippage. i dont know the better brand shift kits so you should ask others what one to get if your getting one.

rjbest · #12 06-25-2008, 10:44 AM

Thanks Matt. The guy who does my work is heavy into race cars so he should know the best "brand" to get.