Greetings, I have a 1997 F-150 4x2, 4.2 engine with 4 spd electronic auto trans, @160K miles. The motor has been replaced with a Jasper reman.

My issue is now twofold. Innitially, after getting the vehicle warm ( 70 mph for an hour or so) when coming to a stop, the entire truck vibrates, engine rpms drop below 400 rpm, and the engine will stall..also occurs when decelerating to a traffic lite or tollbooth. This problem followed the truck after the engine swap, am being told torque converter not locking? Trans is throwing no codes at all. engine will restart immediatly after the stall.

Have towed a 2008 Jeep rubicon on a 2 axle 16' trailer since then, (Well within the 10K max tow weight iaw owners manual) with same issue with no other problems other than the "stumble and stall" upon deceleration and stop. Have only towed this weight 5-6 times in the last 2 years...not typically used for this.

Recently have gotten a single axle R-pod camper, 2200 lbs max, have checked bearings and brakes no issues....but with the overdrive selected "off", the trans will not downshift while going up a grade, any hill for that matter...even on a flat...for instance...running 60 mph, then on a small hill, slows to below 45, won't downshift to maintain speed, even with pedal floored. will shift if done manually.

I guess what I'm looking for is some sage advice on anything I can do to fix these issues other than replacing the trans..I know it's rather high mileage...but any port in a storm....I just don't want to get up into the hills and blow trans gutts all over the interstate.

My ol' girl is in great shape otherwise, and I'm dead-set on fixing her versus replacing her....sorry so long winded....li'l help please?

 

10,000 pounds towing is gross combined weight - truck, truck being towed and trailer. I think the 16 foot trailer, jeep and F150 maybe too heavy.

 

Yep, truck weight 4860, trailer weight 1850, jeep weight 2250..hovering about 9k...but the first issue existed before anything towed. Have only trailered this weight 5-6 times within the last 2 years.

Made sure overweight wasn't the issue, but thanks for pointing it out. Am completely baffled on the 2200 lb trailer causing issues the 5k car dolly/jeep combination didn't, am thinking the trans is on it's way out....

Oh yeah, fluid is fresh & clean, as is filter, and OEM cooler is in tact with no blockages evident.....

 

It does sound like your torque converter is not locking/un-locking properly. If you come to a stop, and your torque converter wont unlock, it will easily make your truck stall. Next time when you are coming to a stop and you can feel it wanting to stall, put the trans in nuetral, see what happens. If it doesn't stall, then your converter is most likely not functioning correctly. If it still stalls, even after you put it in nuetral, then you've got more problems.

 

Thanks keyul. sounds like that's it. 9 times outa 10, engine rpm's will recover to @ 800 and all is fine...that 10th time, I just may not have been quick enough.

Doesn't seem to be much I can do for the torque converter besides changing it. Anyone know how long these 4 speed electronic auto transmissions usually last for, from new till rebuild/replace? Again, this one has 160K on it, and will actually looki at either a Jasper or OEM remanufacture....if I gotta pull it to change the torque converter anyway....1900 +/- plus knuckles/blood/sweat/tears...etc.

 

No specific service life on them, really all depends on too many things like maintainence, fluid changes, do you have a trans cooler, tow package, etc etc. Speaking of that, does your truck have the tow package? My dads 6cy 98 f150 does, I've used that to tow a number of times, 6x12 enclosed trailers, car trailers with other trucks on them. It has the 7 pin harness in the back, an extra factory cooler up front, and the hook up under the dash for the electric brake controller under the dash. Also one huge advantage I found when towing with the 6cyl was to run the 93 octane gas, ran a lot smoother that way.

 

When I went back to re read your original post, I suspect your issue maybe mechanical (since you did not mention service soon light).

With the amount of miles on the truck and the manner of use you use the truck a trans servicing maybe in order.

160,000 sounds like a ballpark range for major trans work (like mentioned before you actually put your transmission to work)

Keep us posted on the repair order, I am sure I can use this information in the future.

I had my E4OD rebuild and while it was out, I installed a B&M extra capacityoil pan.

Just another option to consider. I plan to install one on my F 150 at the next trans oil and filter replacement.

 

One way to determine if it's transmission is to coast down in neutral.
If the motor still stalls it's not the transmission.
I suspect the IAC is sticking closed.
What is supposed to happen on decell is the fuel is cut back, the IAC is closed down just enough to keep the motor from stalling.
If the IAC closes fully, there is no bypass air to keep the motor at it's rated idle speed.
It may be a harness issue as well.
Clean or replace the IAC first.
You usually won't see a code from this type of issue.
A converter lockup stuck engaged should offer a code because the solenoid current operate and release signiture is monitored by a PCM chip..
Good luck.

 

Idle Air control motor, eh?

Will swap it out and see. Had to poke around to see what it actually does, and it makes sense as I'm not getting any codes...and cost-wise is worth a shot.

Will return fire with the results as soon as I get the time to swap ito out.

Tankx!