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-   -   Allison at545 (http://www.airforums.com/forums/f159/allison-at545-132239.html)

mayco 03-12-2015 12:50 PM

Allison at545
 
Does anyone know how much fluid to add to the spec for the tranny cooler on an Allison at545. The tranny holds 5ga but I dont know how much more to add for the stock cooler. Its hard getting an accurate reading on the dip stick. Many thanks for the info.

Mike

shepherd57 03-12-2015 03:49 PM

1 Attachment(s)
Mike
I check mine with the engine running in neutral, Seems to work for me mine is hard to read to. Here is a page from my Allison handbook

mayco 03-12-2015 06:10 PM

Thats a nice sheet.....ill save that. Ill get it out here in the next few days and get her up to temp and look again. Specs say five gallons with the standard oil pan, a lityle under four ga with the shallow pan. Im assumed this has the standard pan but Ill measure that tomorrow. Little over 11" from center line for standard pan. That dip stick gets oil trails up the sides and with clean fluid its hard for me to get a good reading on the actual level. Thanks for that sheet, very helpful.

Mike

choctawmel 03-17-2015 07:30 PM

my oh my.. You have a 545? The po had a 545 installed in my 'silver bullet'. Was a good transmission, but couldn't take much more input torque than the stock(weak) 454.
Mine died and I replaced it with a 4L80e. Turned out the installers of the 545 missed the hole in the crank with the tit of the torque converter is the reason for the failure.
I'm not sure I'm all that happy with the 4L80e. But it is working with a 496cid motor with a lot more torque then the 545 was make to handle.

shepherd57 03-17-2015 07:54 PM

I have the 545 in my Isuzu powered 32.5 it is a good trans but it has no lockup converter and no overdrive. I am thinking about putting in an Allison 5 speed with the lockup converter. It will bolt right in and will need a stand alone wiring harness and Allison TCM to make it all work

choctawmel 03-18-2015 09:03 PM

Quote:

Originally Posted by shepherd57 (Post 1594882)
I have the 545 in my Isuzu powered 32.5 it is a good trans but it has no lockup converter and no overdrive. I am thinking about putting in an Allison 5 speed with the lockup converter. It will bolt right in and will need a stand alone wiring harness and Allison TCM to make it all work

In your application I'd stay with the 545 and change the rear end gear to get the same effect as an overdrive. The 545 has so many clutches/plates it is better than a 'lock up' convertor.
I should/would have done that except I increased the input torque well above the max input for the 545

mayco 03-19-2015 02:17 PM

If you are willing to forgive my mechanical ignorance, could you explain what all gets changed out when changing the gear ratio in the differential? In our case obviously we would want to reduce rpms at cruising speed to reduce wear and tear on the motor. Is the gear change isolated to the ring and pinion gears or all the gears in the rear end? I would assume while having it tore down you would replace all bearings and such. What type of reduction in rpms could be accomplished while still having reasonable lower end torque? Im happy driving at 60-65 mph but 2700+ rpms has always seemed pretty high to me. I would never try to open up the rear end myself, I would pay to have it done. What type of cost are we talking about......ball park? Ive heard and read very good things about my at545 and dont think I would consider messing with it. Especially since I dont have the mechanical abilities to do the work myself.

shepherd57 03-19-2015 06:20 PM

Mike
You could change the rear end ratio to a 4.10 it would have to be done by a rear end shop

choctawmel

I think you will find that the Allison 2000 series 5 speed has more than enough strenght to handle what a 454 can put out they are used behind the Duramax diesel in med duty trucks to 30.000 lbs



Allison-Transmission-2000-Series-Spec-Sheet.pdf


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