3-53 Detroit with Allison AT-540 issues and conversion to different tranny

[TravisMVL]

I bought a timberjack 230D back in June that the previous owner did not really take care of. I bought it cheap, so I am not too bothered by having to fix things, but I'm very confused as to what's up with it's allison automatic transmission.
The previous owner blew the transmission and got a At-540 out of a school bus and stuck it in the machine without hooking up the modulator valve control which hooks directly up to the throttle linkage with a cable (not vaccum controled). The transmission blew on me not too long ago so I bought a rebuilt AT-542 (which is the correct match for the engine rpms), and just installed it a couple days ago. I still need to make some linkage fitings for the modular valve before I can run it.
While locating parts and speaking to lots of people, I was told by just about everybody that the automatics in the timberjacks were bad setups, and that some guys blow the tranny every 6 months, some (for whatever reason) bypass the cooler lines, and that some guys choose to disconnect the modular valve control.
Can somebody shed some light on the history and problems with this engine and transmission hookup?
If this transmission blows on me again I want to find something else that will bolt up the same and be more reliable, possibly switch it to the new process manual tranmission that most of these machines have, but I would like to consider a heavier duty automatic if possible.

[lumberjack48]

The 353 and the Allison is a perfect match, but what most guys don't know is you have to run it like you don't own it, petal to the medal at all times or the tran  will not hold up . You have to keep rpm up to keep trok locked up so the packs don't slip, and to keep it cool. The reason they on hook the mod is with this set up you don't want it to shift on its own, shift it manually. They will not take any slippage or running hot like any auto. I had a S8 with a 353 and a Funk auto, ran it 16 yrs sold it after i got hurt.  [ be care full out there guys]

[treefarmer87]

yep you gotta run it to the floor in a detriot

[barbender]

I can't shed any light on Allisons in this set-up, but we have old Ford tandem end dumps at work, late 70's. Those Allison's are pretty tough in those things, the way they shift makes one think they are going to blow up, but they never do. They let the engine rev all the way against the governor and then BAM! they shift into the next gear really hard.

[ga jones]

353 allison is the perfect setup the AT-545 542 are cheap to replace. 500.00 around here. just run it hard.and dont bypass the cooler. One of the most abusive loggers i ever met has a 240 jack with a 453, AT- 545 and only rebuilt it once in 10 years. And never does any maintance.

[weimedog]

I had two Allison Automatic setup ups in Dump trucks in Colorado. All my work was in the foothill's and about as abusive as it can get on those transmissions. Seems to me a Detroit in front of an Allison should be a happy arrangement! One of trucks had a 6V92 TTA in front of a 753. That truck was bullet proof and surprisingly capable. It was a former snow plow truck from a mountain municipality...can't get a tougher application than that! Couple of things I learned that may or may not apply to your skidder application:

1) If they stay cool, they won't die. We added an extra heat exchanger (radiator) and electric fans. Keep the operating temp below 180 and it will never die.
  a) I used to put temperature indication strips on the trany to sort of keep an eye the operation temps..

2) You can adjust how fast the clutch packs lock up in the valve body..since we worked in the hills we shortened the engagement time and yea..it "thumped' (not slammed) when shifting, but the clutches weren't subjected to lots of slip while engaging.

3) The distributer out there was a company "Stewart Stevenson" in Denver..and they REALLY know their stuff technically! Or at least did ten years ago....a good place to ask questions.

4) In some applications where the speeds were low and temps are high, using a different transmission fluid/oil was called for. (Of course With a C-4 or what ever the current Allison rating is!) Some of the trash haulers used the Rotella T of that time period (1980's & 1990's)...don't know if that is still an option as things have changed! A question for places like Stewart Stevenson!