Allision 545

[batietrees]

545 Allison transmission

Can anyone out there help me with this -- we have a DT360 engine with an Allison 545 transmission --Transmission seems to operate fine, changes and engages-except it gets real sluggish when its forward or reverse- I have to accelerate real hard to get it to move- can anyone give me an idea on how to check it out and where to start with this problem
thanks

 

[dbarton291]

RE: Allision 545

batietrees - 5/30/2009 11:52 AM

545 Allison transmission

Can anyone out there help me with this -- we have a DT360 engine with an Allison 545 transmission --Transmission seems to operate fine, changes and engages-except it gets real sluggish when its forward or reverse- I have to accelerate real hard to get it to move- can anyone give me an idea on how to check it out and where to start with this problem
thanks

Can you please clarify what you're describing? This part "Transmission seems to operate fine, changes and engages-except it gets real sluggish when its forward or reverse- I have to accelerate real hard to get it to move" isn't clear to me.

If you're saying it takes a long time to accelerate and get under way, you should probably do a stall test to see if the engine is making power and the trans isn't slipping.

 

[batietrees]

Re: Allision 545

Yes- I’m saying you have to accelerate really hard initially- but once the vehicle starts moving you have plenty of power.-- Its almost like it has a pressure building problem- like restricted fluid flow or something- but once it starts moving you can ease off the accelerator and have plenty of power
This problem is only in forward or reverse- not 2nd, 3rd or 4th- this problems to be from a stop only.
We serviced the trans - new filter- oil and such-While servicing it we found no debris at all when we checked the pan.- (it response like a stopped up filter)
I don’t have a Allison service manual so can you please explain how to do a stall check on the trnas to check to see if its slipping.
Thanks for you help

 

[dbarton291]

Re: Allision 545

batietrees - 5/31/2009 11:39 AM

Yes- I’m saying you have to accelerate really hard initially- but once the vehicle starts moving you have plenty of power.-- Its almost like it has a pressure building problem- like restricted fluid flow or something- but once it starts moving you can ease off the accelerator and have plenty of power
This problem is only in forward or reverse- not 2nd, 3rd or 4th- this problems to be from a stop only.
We serviced the trans - new filter- oil and such-While servicing it we found no debris at all when we checked the pan.- (it response like a stopped up filter)
I don’t have a Allison service manual so can you please explain how to do a stall check on the trnas to check to see if its slipping.
Thanks for you help

Get the stall speed for engine/trans combination. Engine manufacturer normally has this. It can also be obtained from Allison iSCAAN.

Get to operating temp. CLEAR THE AREA. Set Parking brake. Apply service brakes. Select drive, NOT REVERSE. Go to wide open throttle. NO MORE THAN 30 SECONDS. Record Max engine RPM.

Stall 200 or more RPM high indicates slipping trans.
Stall 200 or more RPM low indicates low engine power, misadjusted throttle linkage, etc.
Normal stall with a complaint like yours, indicates your vehicle probably is just not a hot rod.

On some vehicles with smoke controls, you have to get going down the road and use the brakes to slow the vehicle to a stop while maintaining throttle position to get the stall speed. Smoke controls on the engine limit fuel while starting out (among other things), and can make the vehicle feel like a dog.

If the trans is slipping, you will notice real high engine RPM while you're trying to take off.