Was the trans up to temp? That would actually lead to clutch slippage.
Anything below 1800rpm condemns the TC, anything above is a failure in the transmission. Do you have anyway to carry out a line pressure test?

Try stall testing in R, D and 1.

 

The trans was probably not real warm, but somewhat. I let it run for 15 minutes @ idle, then drove 5-6 miles before testing. I haven't tried stall testing again. I do have a way to test line pressure, but I'm gonna throw a converter in first. I ordered one today with a new filter/gasket and some motorcraft mercon v fluid. It won't take me long to switch it, and if it doesn't solve the problem, I still would be getting a new one if I got the trans rebuilt.

One thing I forgot to mention in the first post. The trans shifts real good, but I never notice the converter on shifting. I talked with my trans guy and he thought it sounded like the converter also. Like I said I'm gonna try this first. If I don't succeed, try, try again.

Thanks again.

 

Couldn't find your old one huh? Of course its a lot of work, might as well put in a new one.

 

No, I couldn't find it. That's ok though. I'm better off with a new one. It's not a bad job with a trans jack. I couldn't count how many transmissions I've removed and installed without one. What an idiot I was.

 

I guess I'm a idiot!

 

OK, I should have phrased that differently. I should have just said the jack makes it a lot easier and I should have gotten one many years ago..

 

haha, I was just thinking about the time I pulled my trans. I used a regular floor jack and lots straps across the frame. Crazy

 

I swapped converters on friday. I went with a florida converter. It's a new converter, not rebuilt. No high dollar converter, 250 shipped to my door with no core charge. Basically its stock. I put a new motorcraft filter and fluid in also. There was some very small powder on the magnet, no big pieces at all.

I'm calling it fixed enough for this truck, it seems to work pretty good now. It doesn't seem perfect yet, but it is way better.

 

Amen to that brother!! I've been pulling them for years without a trans jack. The kids all went together and got me one Christmas before last. Don't know why I didn't buy one years ago. Every time I pulled a trans I would tell myself, "I need to buy a trans jack!"......but I never did! LOL! It was Tyler's idea for them all to get me one.........I think it was so he could use it too! LOL!!!!

 

Hey Darin, so I am just trying to understand...for personal reasons. I think my JW has taken a crap and I think it's the converter. I have never understood 100% how they work. If I stand on the brake and give it throttle, it should not rev to 3000, right? Mine did and then the tires kinda cut loose. I only did it for 3-4 seconds. It shifts great and all that, but it slips if it gets above 170* and then it won't go over 55mph without slipping. It throws the P1720 code (trans slip fault). Acts just like a TC unlocked. It's one reason I thought about putting a lockout switch on it.

I haven't wanted to put this on the forum, but I can't get JW to give me a call back when he can look at it and do the first fluid change. I need an answer because I can drive it, but can't tow with it now.

 

That's the shi!s, old John is giving you the Glenn treatment huh? Hope you get it figured out, I'm sure its guaranteed!

 

Just texted you Glenn. Yeah I am pretty down about it. It's the second time I have had a problem and the damn thing has 30k miles and is 15 months old!

 

Just put that switch man, it works. If my 800k tranny is been taking the abuse ,I dont see why your tranny could to. Also make sure your brake switch is working properly, tou know my saga
Forget the hand shaker,Ill get flame but I never liked manual trannys on a truck, for me is cars manual, trucks auto since most of the towing needs at work are in the city and it gets old really quick specially trying to fit an 40'x 8' flat bed trailer in a 10' wide alley

 

I hear you. Will the switch work though if the TC is bad? It shouldn't be, but why the heck is it slipping? Make sense? Just stuff I don't know.

 

It might help you out(TC lock switch) if indeed you have a brake light issue or something. I texted you back this morning, just missed your text last night.