Compatible transmissions for the M35a3 with the cat 3116

m-35tom said:

i think i remember the allisons with od are 6 speeds. also electronic, so ecu and shifter must be programed. you would not have to use the 6th speed as it may be too high, but length as i recall will be a big problem. no manual trans i know of (that will fit) has enough od so the only option is the 3053 and a gear kit. i spent many years researching this before i spent the 10s of thousands having gears made. it is still the single most practical thing to do and in the long run the lowest cost.

and any duece in good condition is perfectly safe at 65.

tom

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Allison has non-electronic overdrive 5-spd transmissions that will bolt right in.

Tom

what is the model number on the overdrive 5 speed allison?

Yes, Please do tell.

I'm not 100% sure which model it is, but they come on the back of 3120 Cat engines.

Give me a day or two and I'll run down the model number for you.

Tom

PROSTOCKTOM said:

Allison has non-electronic overdrive 5-spd transmissions that will bolt right in.

Tom

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I am pretty sure this is the tranny my plow truck with the cat 3116 has in it . I did a search with the vin # to get the tranny type but I ran into a dead end . The tranny type was not listed . I believe it was not listed because the trucks are custom built for State Of IL DOT . I can tell you when it hits that 5 th gear the rpm's drop drastically. I geuss I can go roll around in the gravel under the truck and see if I can see anything on the tranny indicating tranny model .

The Allison AT545 isnt that sturdy of a trans for heavyduty use. I have had o replace mine in my International S1600!

If you dont mind swaping to a manual what about a Fuller 9spd with OD that should work really well and the size difference isnt much difference than the 3053. That way you have a deep low gears for off road pulling then a highway gear for cruising! You would need to get the number off the side of the trans to see if its a OD model or not as not all 9spd are the same.

The MT653 Allison is a 5spd auto and is also more heavy dty I had it in my International S1954 6X6 Rig that was stolen. only thing is 1st is a granny low and 5th is a 1;1. Its a lil bit bigger than a AT545 as well but should still fit in a deuce. No OD though!

There are sticks avalible to put behind a 3116 . My 97 GMC C6500 was factory 3116 6 speed stick . They are not an over drive though .

Alredneck said:

The Allison AT545 isnt that sturdy of a trans for heavyduty use. I have had o replace mine in my International S1600!

If you dont mind swaping to a manual what about a Fuller 9spd with OD that should work really well and the size difference isnt much difference than the 3053. That way you have a deep low gears for off road pulling then a highway gear for cruising! You would need to get the number off the side of the trans to see if its a OD model or not as not all 9spd are the same.

The MT653 Allison is a 5spd auto and is also more heavy dty I had it in my International S1954 6X6 Rig that was stolen. only thing is 1st is a granny low and 5th is a 1;1. Its a lil bit bigger than a AT545 as well but should still fit in a deuce. No OD though!

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If the MT653 is a 1:1 final drive, it doesn't buy anything, since the 4 spd in it now has a 1:1 final drive.

m-35tom said:

... but length as i recall will be a big problem. no manual trans i know of (that will fit) ...

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while I'm not a proponent of the 3053, the research that I performed concluded the same result that Tom is stating - there just aren't any MD transmissions with OD that are short enough to fit in the space left by either the AT545 or 3053.

every other trans mentioned thus far is likely too long to fit without further modifications (i.e. move the transfer, cross-members, shifter, new driveshafts, etc.). the Fuller 9 spds and even the FSO 6 speeds are a good deal longer than the Spicer and a bit longer than the AT545. also, the trouble I found with the FSOs (which would have worked with my swap) was sourcing ones with OD gear sets since 90-some% of the 5 or 6 spd FSOs were spec'd with direct drive for around-town box trucks .

I don't recall the length of the AT1545 (which would at least give you a lock-up converter for a few more mph).

I'm also going to assume that any 5 spd Ally is going to be longer than the '545.


hmmm - kinda makes you wonder if the '545 transmission was chosen because it was the only one that would fit without extensive modification...?

Since it doesn't look like an auto trans will fit, are there any manual trans that would mate easily with cat in the existing space while providing more gearing and improved top end? I would actually prefer an manual anyway. I know that mods would have to be made but I think it would require less than re-configuring for a longer auto trans. Right?

RW, have you read the previous posts? it would bolt right in.
tom

Tom,

I take it that you are joking and will leave it at that.

I have come up with a few more (serious) questions though. Considering the increased RPM that the CAT 3116 can deliver over the multifuel, if it were relatively easy to go back to the spicer, then the top speed should improve considerably over the Allison. How hard would this mod be?

Also, If the transmission is such SOB to improve speed, is there any way to get more top end out of the transfer case? Basically, make the high range gearing a little higher (say 10-25%)?

joking? no, not really. it has been mentioned earlier that going back to the spicer might be the bast option since a od auto will not fit and/or does not exist.

i am not aware that the cat can really turn that much faster. if it could then there would be no need to change trans. it should be relatively easy to go back to the spicer and since 44% od is available, (.69), that would be the best choice. you can get gears made for the transfer case but it would affect all gear speeds and be rather expensive. the trans already exists.

tom

m-35tom said:

... Since 44% od is available, (.69)...

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... 31% ??

.69 od = input turns .69 and output turns 1

.69 x 1.44 = 1

44% increase in rpm

the formula is ((y2 - y1) / y1)*100 = your percentage change, where y1 is .69 and y2 is 1.

so it really is almost 45%, i just rounded down.

tom

Tom,

I have read all of the other posts and I do recall where it was said that another Allison would bolt right on but no one ever validated that or provided the information on exactly which Allison transmission they where referring to. Also, just because it will bolt onto the Cat does not mean that it would fit in the available space without frame modification, which is the problem that others have pointed out (in this same thread).

I have had both a A2 and an A3 and I would typically limit the rpms of the A2 to about 2,200 and the A3 to 2,650. Basically I can squeeze out about 450 more rpm from the Cat which should increase the top speed by about 20% over the multifuel, if paired with the spicer. So, the Cat can turn faster (or at least I am willing to turn it faster) and contrary to what you said, it does need something changed to improve top speed because 48mph with the automatic Allison is too slow for me.

Rambling Wreck said:

Tom,

I have read all of the other posts and I do recall where it was said that another Allison would bolt right on but no one ever validated that or provided the information on exactly which Allison transmission they where referring to. Also, just because it will bolt onto the Cat does not mean that it would fit in the available space without frame modification, which is the problem that others have pointed out (in this same thread).

I have had both a A2 and an A3 and I would typically limit the rpms of the A2 to about 2,200 and the A3 to 2,650. Basically I can squeeze out about 450 more rpm from the Cat which should increase the top speed by about 20% over the multifuel, if paired with the spicer. So, the Cat can turn faster (or at least I am willing to turn it faster) and contrary to what you said, it does need something changed to improve top speed because 48mph with the automatic Allison is too slow for me.

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the A2 should go to 2600, 2200 is real low, about bad filter rpm

Ron,

I understand and that is why I said "typically". That example was really more of an exercise in math than it was on "cruising" red line opinion. For my application and from my experience, I should be able to cruise at about 20% higher rpms with my Cat. So all other things being considered equal, including transmissions, I should be able to go about 20% faster with the Cat. So... back to my question, how hard would it be to put the spicer in there or is there in fact an Allison (automatic or manual) that would fit and provide more top end?

tom, i don't consider 450 rpm much of an increase, and with out lockup i agree it is just no good.
if you look at post #11, i suggested the spicer early on, you must have missed it.
as for an overdrive auto, allison NEVER made one in the AT or MT line, they were all 1:1 final drive.
allison made 1000 and 2000 series autos but they are electronic and would cost more than the truck could ever be worth to install.
the first step would be to measure an a3 and an a2 to see if the rear of the flywheel housing is in the same relitive position. if it is the rest should be pretty easy. mainly just need a flywheel and clutch. this would give you a truck that would comfortably drive 65+

tom

if you've driven an A3 with the Cat@2650, you would wish for ANY taller gears.....