Tranny not shifting when over 3000 rpm

bm40t4r

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Recently my t4r has been having problems shifting when over 3k rpm. It seems to happen most frequently when I am accelerating fairly quickly from a stop or even when going at highway speeds and I punch the gas a little bit. Also it will happen when going up a hill, so basically anytime I am accelerating over 3k like previously stated. When it first started happening it kind of felt as though the engine was starved for gas so I changed the fuel filter hoping it would be a quick fix but that didnt solve anything. It is as if the tranny simply wont shift and the runner will start to shake. Any ideas on what the problem could be?
 
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I'm experiencing similar symptoms, although mine happens around 1600-1800 rpm, and the tranny does shift up through the gears. Still have the "starved for gas" off and on from a stop and when under load in that rpm range. I changed my fuel filter and cleaned my MAF, didn't make any difference but both needed it anyway. Let me know if you get anywhere with yours, and if I fix mine I'll try to help you out too.
 
Does it shift normally if your accelerating normally? I can't tell you the least time I had mine over 3,000 RPM. Can't hurt to try taking some of the slack out of the throttle and lockdown cables. They do stretch over time.
 
I am having the same issue. I recently cleaned the maf, changed the fuel filter, changed engine oil, and changed trans fluid after my Uwharrie trip. I have a slight whine coming from somewhere whenever I accelerate. The shifts feel sluggish from 1st to 2nd and it gets firmer as the transmission warms up...I am at a loss for ideas for the moment. Prolly just run it till it dies and change whatever breaks lol

my ideas so far.......
torque converter?
failing tranny?
failing fuel pump?
 
I really hope it is not a problem with the tranny. Also PitbullRescuer it is very easy to reach 3000 rpm when passing someone on the highway or going up a steep hill or mountain at highway speeds. For the most part it is not a huge problem but it gets annoying when I am trying to pass a slowpoke on the highway or climb at any decent speed. I am hoping that maybe someone that has had this problem in the past will chime in on what they did to fix it!
 
Trying to help you out here. How does it shift normally? When you say it doesn't shift above 3000, what exactly happens? Do you have to let off and slow down before it'll shift again? Or does it go to redline and then shift? Need more info to try to help you diagnose it.
 
Trying to help you out here. How does it shift normally? When you say it doesn't shift above 3000, what exactly happens? Do you have to let off and slow down before it'll shift again? Or does it go to redline and then shift? Need more info to try to help you diagnose it.

Normally it shifts fine without any hiccup of any kind. At the point where it should shift but doesn't it begins to cut out and does not stop cutting out until I let off the gas for at least a few seconds and then it is fine once again. I should also note that it doesn't cut out EVERY time I reach 3000 rpm. It is fine if I very slowly ease it up but as I have mentioned when passing and climbimg hills this is not always possible.
 
So it's falling on it's face under load. The good news is that your trans is fine. And it runs okay and doesn't do it all the time, your compression is good too. So either you have a clogged fuel filter or a weak fuel pump. Or, you need spark plug wires. Throw a good tune up on it and you should be good to go.
 
Yeah I have replaced the fuel filter so I guess testing the fuel pump is next on the list. Thanks for the suggestion!
 
Shot in the dark, but make sure the throttle "kick-down" cable to the transmission is adjusted properly. Try tightening it up. On the throttle body, its the cable that is the furthest back towards the firewall.
 
Shot in the dark, but make sure the throttle "kick-down" cable to the transmission is adjusted properly. Try tightening it up. On the throttle body, its the cable that is the furthest back towards the firewall.
I adjusted that cable awhile back but it is definitely worth checking again in case something loosened up.
 
So it's falling on it's face under load. The good news is that your trans is fine. And it runs okay and doesn't do it all the time, your compression is good too. So either you have a clogged fuel filter or a weak fuel pump. Or, you need spark plug wires. Throw a good tune up on it and you should be good to go.

I think you're right about the tranny, I'm going to pull spark plugs today and have a look. Is it possible for the MAF to just go bad? Thought I read on one of these forums that can happen...Had to have the fuel pump replaced on my chevy and it was $750+
 
Need help with this same problem for my 3rd gen T4R

Did anyone actually solve this problem with their 3T4R?

Did replacing the fuel pump make any difference?

I have the same problem and would like some definitive advice on what to do.
 
Get an obd2 reader of sorts that you can monitor sensor signals. Then monitor the throttle position sensor, MAF, and O2 as well as fuel trims.

Could be lots of things so you need to narrow it down.
 
I once had some issues similar to what you were describing. I took it to a mechanic and that idiot said it was the transmission and it needed to be replaced. I knew it wasn't the transmission because I would take it out of overdrive and shift it manually into what gear I needed when climbing or passing and the transmission worked fine. I had the TB, fuel filter, MAF and fuel tank cleaned. The problem went away. I had some bad fuel and until everything was cleaned the motors power was not right at higher rpms.
 
I'm actually having a similar issue with my 97 runner, finished acquiring all the parts for a full tune up including some upgraded 4 nozzle injectors, plugs, wires, TB gasket, timing belt kit (just got over 200k so its time) and replacing fuel filter and did a full fuel system treatment already hoping to fix the issue that way. Does it seem like when it falls to shift its almost as it it hits a rev limiter way to early? I plan to do all this maint along with a liquid moly engine flush this weekend and will try to update after about the progress.
 

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