NottsJeep

Hi all, first post so hopefully i can get some help/ideas on this.....

I've driven many automatics in my life and with all I've found that when travelling at anything above 30 mph that if i feel i'm slowing down then i can put the accelerator down and it'll drop down a gear automatically to pick up the speed. Some have had kick down buttons behind the pedal and some haven't but all of them have dropped down to assist in picking up speed, however.....
I've got a 2001 WJ 3.1TD and last year we took it to Cornwall for the first time towing our Caravan and noticed that when we hit ANY hill (regardless of gradient) that it pretty much slow down to a halt (maybe not a halt but down to about 30 MPH on a 50 - 60 road) and it would not drop down gears to accelerate, it just stuck where it was until we got to the top. Since that I've noticed that it's been doing the same even without the caravan on.It seems fine at picking up speed going downhill or flats
I also noticed it was very slow pulling off from standing when in Drive but if i manually selected 1st then it seemed pretty quick so i mentioned it to a friend and he advised it could be the transmission fluid so i've now changed the fluid and the filter and put in some Lucas Transmission Fix and although it seems faster now pulling of in Drive but still seems to be struggling on any gradient but it also seems when it's moving from 30 to 40 mph ? Just as a note though (which is the odd bit) that once i hit about 40 mph the kickdown seems to work fine and i can tell it dropping down the gears to accelerate above and beyond 40 mph.
I've checked the throttle valve cable and this seems fine (as far as i can tell), i have this one if it's relevant:
So i'm not sure if this is how these vehicles are or if they should have a bit more "poke" when they it hills ? Again it does seem overall that it's fine when flat.
Hopefully this makes sense but anyone got any views/ ideas on this ? I may need to take it out and do some testing to pin point exactly where the problem is but i think I've about covered it
Thanks in advance
Ian

97grand4.0

um no there is something wrong with it. welcome to the forum.

NottsJeep

Well at least i know i need to fix something. I've been doing some more investigation and a few people have said possibly the TPS sensor or throttle cable, do you think this would be a likely scenario for either of these ?

Thanks

97grand4.0

Looks like the 2001 wj had either a 45RFE and 545RFE automatic transmission.
Unfortunately I am unfamiliar with either of these. However to answer your question re the tps or other sensors, an inexpensive scan tool with graphing can be had on ebay for less than 50 quid. On the graph side you can look in real time at the tps. If you see any dipping of the signal whatsoever replace it. Also they do tend to wear out on the low side where you are feathering the gas off idle most often, and you will see a percentage of open reading that may be higher than it should be. On mine this is about 16% open at idle. I just replaced one that was into the 18s and spiking too. Much better drive ability.
If the tranny has solenoids, which is highly likely, and if you have high mileage, you should consider changing them. Fleabay had some great prices I have done this for 2 jeeps. Always good to change the filter and fluid a couple times too.

NottsJeep

Thanks 97grand4.0 but funnily enough I've just come back from a test drive and it's now working fine. It seems the throttle cable sheath that is going into the top of the cylinder on the video above has a circular discs around it and on mine it was sitting on the end of the cylinder which from where i was looking seemed to be where it was supposed to go however I've removed the locking clip today and realised that this circular disc is supposed to go down into the cylinder so I've pushed it as far down as it would go and then pushed the accelerator down fully and then put the locking clip back on and it seems to have reset itself and is working fine.