5r110 problem - false neutral

webb06

Active member
Joined
Aug 14, 2012
Messages
3,888
Reaction score
9
Location
Seneca, MO
I don't do this much but I need a little help with a customer's truck

2007 f250
studs, deleted, custom gearhead tuning
stock trans

if the truck is in park or neutral and revved above 2500-3000 rpm and then shifted to drive or any other gear the truck won't move, almost like a false neutral.

to get the truck back in gear you have to power stall it (have the truck in drive or reverse with foot on the brake and rev engine to atleast 2000 rpm) then it will slam in to gear REALLY hard, once back in gear it drives and shifts perfect

truck drives and shifts fine as long as you don't rev it up while in park or neutral.

i've searched all over trying to find if someone has a duplication of this problem with no luck.

i know the simple fix is to tell the customer to quit revving the truck up, but now that he knows something is wrong he won't be happy until it's fixed.

thanks for any input
 

yannie

New member
Joined
Aug 17, 2014
Messages
23
Reaction score
0
The little toilet paper roll transmission filter??


Sent from my iPhone using Tapatalk
 
Joined
Sep 12, 2013
Messages
832
Reaction score
0
Location
Oroville, CA
I don't do this much but I need a little help with a customer's truck

2007 f250
studs, deleted, custom gearhead tuning
stock trans

if the truck is in park or neutral and revved above 2500-3000 rpm and then shifted to drive or any other gear the truck won't move, almost like a false neutral.

to get the truck back in gear you have to power stall it (have the truck in drive or reverse with foot on the brake and rev engine to atleast 2000 rpm) then it will slam in to gear REALLY hard, once back in gear it drives and shifts perfect

truck drives and shifts fine as long as you don't rev it up while in park or neutral.

i've searched all over trying to find if someone has a duplication of this problem with no luck.

i know the simple fix is to tell the customer to quit revving the truck up, but now that he knows something is wrong he won't be happy until it's fixed.

thanks for any input

He's going to need a trans. It's either got some smoked clutches or the valves in the pump are worn and sticking.
 

webb06

Active member
Joined
Aug 14, 2012
Messages
3,888
Reaction score
9
Location
Seneca, MO
Have you tried it with stock tuning just to eliminate that as a possibility too?

I suggested that to the customer. Don't think he's tried it yet

He's going to need a trans. It's either got some smoked clutches or the valves in the pump are worn and sticking.


Can you explain to me what is happening and why is only happens when revved up?
 

Mdub707

Active member
Joined
May 18, 2011
Messages
5,079
Reaction score
0
Location
Mohawk NY
It literally makes no sense why it would change, revving it up in park. I asked someone else about this, that I trust with transmission stuff, especially 5R stuff. His recommendations were try it on a stock tune first, and then put a gauge on to watch line pressure when shifting gears and see what it does. Both him and I agreed we think there is other funky stuff happening, or will be happening. I doubt this is the only symptom.
 
Joined
Sep 12, 2013
Messages
832
Reaction score
0
Location
Oroville, CA
I suggested that to the customer. Don't think he's tried it yet




Can you explain to me what is happening and why is only happens when revved up?

I would lean towards the Regulator Valve being worn and sticking. Reving it up jacks the line pressure and forces it to move. I'll try to find one I have getting around that was smoked. Sonnex makes a kit to bore and sleeve both the main regulator and the converter valve.
 

Mark Kovalsky

Active member
Joined
Jul 11, 2011
Messages
1,181
Reaction score
4
Location
SE Florida, USA
Are you saying that it won't go into gear when the engine speed is at 2500 RPM? If that's the problem you can't fix it. That is the software keeping the engagement from happening so that the transmission isn't destroyed.
 

webb06

Active member
Joined
Aug 14, 2012
Messages
3,888
Reaction score
9
Location
Seneca, MO
Are you saying that it won't go into gear when the engine speed is at 2500 RPM? If that's the problem you can't fix it. That is the software keeping the engagement from happening so that the transmission isn't destroyed.


No. Truck is in neural or park and gets revved up above 2500 rpm (to show a guy what the exhaust sounds like) drop it in to drive at idle and go to take off and the truck won't move, no matter what gear its in.

When in drive or reverse with foot on the brake and revving the truck it will eventually slam back in to gear and drive like normal.
 

TurboM700

New member
Joined
May 18, 2011
Messages
940
Reaction score
0
Location
Minnesota
Sounds like a pressure control valve is sticking. Like other have said.

Think of it this way when you rev it up the valve starts to open to bleed of pressure(pump is pumping more fluid) valve then sticks in that postion.

In gear you rev it up again till the valve starts moving and it frees it's self.

I'm not 100% familar with the 5r100 valves but this would make the most sense.

Either way the transmission is coming out.

Mike
 

Mark Kovalsky

Active member
Joined
Jul 11, 2011
Messages
1,181
Reaction score
4
Location
SE Florida, USA
Why would the trans need to come out? If it is a stuck pressure control solenoid, and that's possible, those are in the pan. The pan needs to come off, but not the trans.

It could also be caused by low fluid, a bad pump, worn out seals in the clutches, or a faulty internal filter.
 
Joined
Sep 12, 2013
Messages
832
Reaction score
0
Location
Oroville, CA
Why would the trans need to come out? If it is a stuck pressure control solenoid, and that's possible, those are in the pan. The pan needs to come off, but not the trans.

It could also be caused by low fluid, a bad pump, worn out seals in the clutches, or a faulty internal filter.
I'm talking about the actual valve in the pump.
 

TurboM700

New member
Joined
May 18, 2011
Messages
940
Reaction score
0
Location
Minnesota
Why would the trans need to come out? If it is a stuck pressure control solenoid, and that's possible, those are in the pan. The pan needs to come off, but not the trans.

It could also be caused by low fluid, a bad pump, worn out seals in the clutches, or a faulty internal filter.

I'm talking about the actual valve in the pump.

What Luke said. I was thinking the valve in the pump is sticking.
 

Tim lamica

New member
Joined
Jul 31, 2017
Messages
1
Reaction score
0
Same problem

Has anyone found an answer to this problem ? Ive had my truck at the shop for 3 months...trans has been rebuilt and torque has been tested... driving down the road truck shifts how it wants, and at a stop seems like starting in 5th...if u rev it to 2500 rpms while in neatral or park, let idle, then put in drive nothing until u rev to 2000 rpms then slams into gear... truck literally can not break tires loose even trying to boost it...im stumped, any info would be much appreciated !!
 

Latest posts

Top