Hi guys. I have been having a serious problem with a 2005 CMP25 which has to be accelerated in order for transmission to engage. The problem is that the unit jolts the load when accelerated to up to 1000 rpm in order for the truck to start moving. Transmission has been overhauled as well as the trans valve assy. I just changed the valve assy to a brand new unit and problem still persists. Also if I rev the engine too much in idle, it will overheat due to the hot climate in my country.
Any help will be appreciated.
Regards,
OB1
Showing items 1 - 14 of 14 results.
Thanks bbforks and Jplayer
We'll look into the converter. Let you guys know if need more advice.
Regards,
OB1
dont most trucks have a torque converter test port on the control valve?
There should be ports for overall pump pressure, clutch pack pressure (fwd and reverse) , and torque converter and possibly even inching circuit pressure.
You'll need the service manual to tell you which ports are what and where they are.
I'd hook a guage to this and see what pressure your getting at idle versus when its rev'd up @ the torque converter port. This could reveal alot. You should be getting some kind of pressure at idle and that should increase as you rev up the engine. There is a minimum and max reading you should have.
Yes a torque converter can break and even wear out. This would explain no movement at idle as oppsosed to rev'ing up the engine and getting the jerk and then movement.
Do you have a service manual on the truck? Somewhere in the torque converter feed/discharge circuit there should be a check valve to keep the converter from draining down fluid. Does the trans jump only after the engine's been shut off or also if the unit's been idling in drive/reverse? Or the converter itself may be faulty-mechanically broken inside. Did you find any metal shavings during the rebuild you couldn't account for? I'd check the stall speed against the spec
Nothing was done to the torque converter. What should be done with it?
bbforks has a valid question
did you do anything with the torque converter? or just throw the old one back in there?
When the overhaul was done- was the torque converter rebuilt? Perhaps the jolt is from the converter filling with oil and then transferring power- just a thought
Thanks
andrewk: I am being told the pump is OK because pressures are OK, Is there another way of testing to see if it is bad?
mrfixit: axle and tranny were disassembled completely, so has been gone for a while now
The truck works fien, except when you want to move from compete start, thet truck tends to jolt after a few seconds. Customer does not like this because the loads they carry may fall
Any other suggestion?
I would think the rag is stuck on the pump sump screen
Id fit a new charge pump then
Guys
I've been dealing with this serious problem since last year. We overhauled the transmission and changed the control valve, yet problem still persists. Anyone have another idea of what else we would need to check? By the way, we found out the problem started after the truck had a higher level scheduled maintenance where the apparently a technician left a piece of rag inside one of the axle housings!
Again, any comments will be appreciated.
OB1
Thanks guys. The transmission is doing better now, but after a few hours of working, it begins to show the same problems as before. Not as it used to be, but the problem still persists. I will check this valve you are mentioning and see if it helps.
Thanks,
OB1
rogeriwt could be onto something here, i once had a similar problem with a truck that someone had recently changed the trans filter, The thread that the filter screws to has a valve inside it and on my truck the thread had unscrewed a couple of turns out of the transmission and the valve was not seating correctly,
Removed filter, tightened thread up in trans, refitted filter and all was well
Thanks rogeriwt. We'll look into to it.
Regards,
OB1
OB1,
It seems like you have done everything. The only thing I can think of is that there is a regulating valve in the oil filter fitting. Maybe that is messing up.
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