Tranny Acting Up ..

LAIRD7_3 · Jan 22, 2014

Hey guys, i'm stumped.. I've searched and searched, but cant find anything that matches my symptoms. Lately my truck will lung while light acceleration, the RPM will drop off then jump back up again, like I keep tapping on the throttle. The RPMs will vary about 300-400 RMPs. Now it doesn't do this all the time, its hit or miss, but usually more off then on. If I am under mild or heavy acceleration it shifts great and there is no problem. Truck has intake exhaust and BDP chip, truck will do this no matter what tune it is on. If there is any questions or if anyone can give me some insight, it would be greatly appreciated. Thank you.

backwoodsboy · Jan 23, 2014

At what speed is it doing this? Torque converter locked up or unlocked?

Montgomery P-Stroke · Jan 23, 2014

Got access to a good scan tool like AE? Could be a dead spot in your pedal sensor or anything else motor related. Oil in ICP sensor plug? Injector harness good? Don't sound like fuel pressure if it is fine under full throttle. Need a good scan tool so your not just shooting in the dark cause there is only so much you can check without one.

Ovalboy20 · Jan 23, 2014

The 95 I used to have would all of a sudden jump rpms under light throttle or towing and it was because the speed sensor in the rear on the axle was going bad and the torque converter would be locking and unlocking a lot and would make the tranny temp go up. Under wot it was always good

smokenstroker99 · Jan 23, 2014

My truck was doing this a couple years ago. I changed the throttle position sensor and it hasn't done it since

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LAIRD7_3 · Jan 23, 2014

Appreciate all the responses! I mostly notice it at low RPM and going around 35-40, but I feel like it is unlocked but trys to lock and cant.. if that makes sense. Truck only has 70K on it so I would hope the tranny wouldnt be going out or anything too major. Truck was all stock when i bought it, 20K miles ago.

Montgomery P-Stroke · Jan 24, 2014

First one in my truck only lasted to 60k but it had a hard life with the two previous owners which I know. The reman in it now only has 45k on it and sometimes it does some funny shifting. Without a chip these trannys are okay but when you start adding power and a heavy foot they don't seem to like it too much.

farmall99 · Jan 25, 2014

LAIRD7_3 said:
Appreciate all the responses! I mostly notice it at low RPM and going around 35-40, but I feel like it is unlocked but trys to lock and cant.. if that makes sense. Truck only has 70K on it so I would hope the tranny wouldnt be going out or anything too major. Truck was all stock when i bought it, 20K miles ago.

Mine does that too, but only in the hot tune. So it may be a tuning issue. You might pull the chip out and see if it still shifts bad, if not I'd get in touch with BDP. I read somewhere before that they revised their tunes to where they didn't do that anymore.

LAIRD7_3 · Jan 29, 2014

farmall99 said:
Mine does that too, but only in the hot tune. So it may be a tuning issue. You might pull the chip out and see if it still shifts bad, if not I'd get in touch with BDP. I read somewhere before that they revised their tunes to where they didn't do that anymore.

Its not the tune, I have taken the chip out and it does the same thing. It is only when im at a steady cruising speed, tranny shifts awesome when I hammer on it. So that makes me think that it might be the TPS, just looking for reassurance.

lincolnlocker · Jan 29, 2014

Sounds like speed sensor or throttle position sensor. What codes came up?

live life full throttle

LAIRD7_3 · Jan 29, 2014

lincolnlocker said:
Sounds like speed sensor or throttle position sensor. What codes came up?

live life full throttle

Havent thrown any codes, I have friday off so ill be digging into this a little deeper. I dont have a code reader so ill have to run down too napa. I have the adjustable pedal too :doh: so im hoping I can clean the connectors a bit if it is the TPS

lincolnlocker · Jan 29, 2014

Just cuz the cel isnt on doesn't mean that there isnt any soft codes.... you will need a good scanner to pull codes. Snapon, mac, otc genesis, and AE types of scanners are what you need to read soft codes.

live life full throttle

LAIRD7_3 · Jan 31, 2014

UPDATE

Well I went down to my local parts store and had no luck pulling up any codes at all.. Thought that was a little weird since I have thrown overboost codes multiple times. I pulled my pedal assembly off and checked the plug and sensor to see if maybe there was dirt and who knows what that might be causing a bad connection, it was super clean. Now im left puzzled :fustrate:

mustube · Jan 31, 2014

Your truck isn't obd2 compliant so the parts store scanners won't pull much if anything out. You need a fancy scanner to see what codes are stored.

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lincolnlocker · Jan 31, 2014

LAIRD7_3 said:
Well I went down to my local parts store and had no luck pulling up any codes at all.. Thought that was a little weird since I have thrown overboost codes multiple times. I pulled my pedal assembly off and checked the plug and sensor to see if maybe there was dirt and who knows what that might be causing a bad connection, it was super clean. Now im left puzzled :fustrate:

Where do you live? Maybe a member near you that could help.

mustube said:
Your truck isn't obd2 compliant so the parts store scanners won't pull much if anything out. You need a fancy scanner to see what codes are stored.

Sent from my XT1058 using Tapatalk

What he said^^^

live life full throttle

LAIRD7_3 · Jan 31, 2014

lincolnlocker said:
Where do you live? Maybe a member near you that could help.

What he said^^^

live life full throttle

live in Washington State, but my buddy has an edge insight, could I hook that up to read a code or is that a dumb question..

lincolnlocker · Jan 31, 2014

LAIRD7_3 said:
live in Washington State, but my buddy has an edge insight, could I hook that up to read a code or is that a dumb question..

I have no idea how that hooks up to the truck.

live life full throttle

farmall99 · Feb 2, 2014

Edge Insight should pull up most codes. I do know that I've seen VSS, TPS and other transmission codes before on my insight.

LAIRD7_3 · Feb 5, 2014

Ok my powerstroke brothas! Turns out my buddies brother has some fancy Snap-On scanner deal and was able to pull a code for my TPS, and show me how the throttle had a dead spot and would drop off at certain positions on the same little unit. Pretty dang cool! I ordered up a new pedal from RockAuto, and it should be here friday :thumbsup: so hopefully that solves my problem. Thanks again for all the patients and help from ya'll!