Just got a new 2019 5500 and figured some people might think some of this is interesting. It does not use a GM T87 TCM. It is using an actual Allison TCM and I have to assume actual Allison programming. It's shifting strategy seems quite different than a pickup. It appears to lock the torque converter in second gear even not in tow haul but tow haul definitely holds gears longer. With the exhaust brake on in tow haul the exhaust braking feels insanely strong. If anyone is familiar with how the exhaust braking is on medium duty trucks (Kenworths ect..) with Allison's you know what I mean. That's how aggressive this is. The TCM tag says A61 which I haven't seen that TCM before. The ECM shows E41 still like a normal L5P. The owners manual calls the engine an "L5D". I have attached pictures of this stuff. I also attached the picture of the transfer case because it is MASSIVE! I just thought this stuff was interesting. This may or may not be the correct section to post this but I thought it was close enough.
New 2019 5500 random ECM/TCM info
- Thread starter buick455
- Start date
Get under there and get some pics of the trans!
Wonder if it’s a 2000 series.
How many gears? 6 speed still?
Wonder if it’s a 2000 series.
How many gears? 6 speed still?
The TCM shows it as a 1750RDS RDS stands for Rugged Duty Series. Looks just like any 1000/2000 series case but it has the SAE bell housing it looks like. The transmission crossmember seems stout. I really wondered about that considering all of the old tail housings that cracked definitely with the size of this t-case. Honestly I've only drove it once so far. Pretty confident it's a 6 speed. I'm not at the shop now so I'll have to get pictures this week. It is a Meritor t-case.
It does not have a PTO but the PTO switch is in the dash and the PTO RPM set points do still work which is sweet. I believe they are 900, 1400, and 1900. You can also set any base PTO RPM under 1500rpm you want if you use the accelerator pedal to get to your RPM choice then select the PTO switch. For example if you want 1050rpm, with the PTO function off you raise RPM with the accelerator pedal to 1050 then hit the PTO switch and your base rpm is now 1050 but you can still select the 1400 and 1900 also. Pretty cool. The converter locks up when in PTO mode also and you can feel it lock if you select your own base rpm. I wonder what converter is in this. I have access to the Allison parts system so I'll see if I can find out from the serial number.