Need some help gents:

I have a 2001 Expy 4.6. If I'm coasting at about 10 mph then floor it, my truck starts to buck for a couple seconds then jerks forward and goes. The "jerk" feels like someone has rear-ended me. I'm thinking it has something to do with the tranny. I just replaced the fluids in the pan and also the filter about 6 months ago. I did not drain the TC. The truck has 47k miles on it. Any thoughts?

Thanks,

Anthony

 

I would post this one on the engine forum; I don't think your trans is acting up. It sounds more like ignition, MAF, IAC, etc.

To be honest, if someone floored me, I would buck and kick also. Consider: 4000# vehicle in 2nd gear and idling engine with probably 18 - 20 in tires, dry road with plenty of grip! Floor it too many times and you'll start breaking parts that probably won't be covered by the warranty!

 

cliles55,

I respect your opinion but highly disagree with it. First of all, there are times when you rely on "flooring" it. Examples would include merging into traffic, crossing an intersection. I'm not sure where you live but at least where I live you sometimes rely on "flooring" it. I would hope that the engineers at Ford have considered this thoughout the years regardless of weight, tire size, etc. If Ford's parts ARE breaking because of "flooring", it would definately explain why their sales dropped 17% this quarter and all other manufacturers had increases in sales.
Anyhow, I doubt the problem is related to ignition or coil packs because they are all brand new. I suspect the tranny because of the "jerk" that I get when it ultimately engages; thus my reason for posting here.

Anthony

 

Check your 1-2 and 2-3 accumulator piston springs (depending on which shift the problem is occuring), probably have a broken one.

 

01screw,

how difficult is it to check the accumulator piston? Does the tranny have to be removed?

 

I did a search and found this link for changing accum spring on a MKVIII; I don't know the similarities of your trans. and the MKVIII but I thought it might help you. Slightly more involved than changing the trans. filter.

http://www.markviii.org/LOD2/1_2_Accumulator_paper.htm

Best of luck. Let us know how it goes.

Curt

 

They are both 4R70W transmissions, so it will be identical.

 

It's a few things... not just one... if you ask me... but what the hell do i know lol...... I too own a ford... lol... a lot of people do....... ok..... your suv is not made for what you doing... that is the problem..... there is nothing rong with you ride... it's your foot....... ( i have had the same thing happen to me in a f150....and other ford suv's trucks, ect....... the car does not have the tranny to handle the power your creating when you punch it.... the slap , jerk is the tranny..... I believe from my xp... there is nothing rong with the suv......


Ps.... try a break stant....... rost the tires if the car will and after the tires are spinning let off the break .. once you get so far.... you will too get the jerk you are discribing......

Good luck........