939 retarder ???

[73m819]

Does anybody know if the auto transmission contains a retarder but not hooked up, the reason I ask is that Cranetruck's 5t 8x8 had this in his trans. which he hooked up and it worked fine. A working retarder sure would help controlling down hill speed with out using the brakes. A jake brake has it's limits with a slip-a-matic. (if not in lockup, there will not be any effect)

 

[machinist75]

You talking about a 5 ton or a deuce a3 automatic? May have put it in the wrong place.

 

[73m819]

Thanks, I will get it moved.

Could a MOD please move this thread to 5t mods.

 

[jatonka]

Retarders were used in the MT series of Allisons in the 60's and 70's, I had an International, 1972 diesel 10 wheeler with an MT41 and a 3 speed auxillary box. It worked fair. They create a lot of heat in the torque convertor. I own a 915A1 with 400 Cummins and Allison HT 750 and a Jake brake, and that combo will haul you down in ahurry. I pull a 22,000 pound lowbed with up the 28 tons on it and it really holds back on the hills. JT

 

[seano11]

Interesting

 

[cranetruck]

Hey Ron,
Like JT says, the MT series (military TX200-6 in my case) has a built-in hydraulic retarder. The Army never had it linked up to a floor pedal, but the 1969 m656/xm757 vehicles have mounting holes for one. I have only verified that the retarder actuator on the transmission is present... never used it.
This transmission locks up in all gears and there is a fair amount of engine braking at all times, sufficient for an empty truck, IMHO.

 

[rustystud]

73m819 All the "MT" and "HT" trannys had the retarder installed. Weather the valving is installed is another thing.