Hello all,
I am looking to update my 1968 ford c 950 it has the original 534 boat anchor with 16000 miles but runs like new. I would like to remove the fuller 5 speed and replace with an allison auto. Back in the day they used an allison mt 42 but i was wondering if there is something more modern without any electronics i could use. Also what bellhousing to use not sure how to mate them up I think i have a SAE #2 bell housing but not sure any help would be greatly appreciated.


Mudslinger2

 

Hello, yes you are correct, back in the day the Allison of choice (up until 1972) was the MT42 6 speed behind the 401-477-534 engines.

Later versions used either the MT640 (4 speed) series or the MT650 (5 speed) series. There are several sub groups in each - for example there is a MT641, MT642, MT653 and so on.

Do not get sucked into a AT540 series, they are a lighter duty trans not really suited for heavy hauling. (they are ok if you stay within Allisons max GCWR ratings though, which I can guarentee you is less than the GCWR on your truck with a stock 534)

Probably the best bet is look for a entire donor truck for the entire setup as trying to piece this all together from various sources can be fustrating and expensive.

Things to think about - do you need a PTO? Not all newer Allisons have that provision. Parking brake on the rear of the tranny? Is your rear axle a single or two speed? Is your existing manual a OD 5th or 1:1 5th? The Allisons that we are taking about here are 1:1 top gear.

Since you have a 1968, It might be easier to get a MT42 setup as on the older trucks it would be more of a bolt in thing... And since the entire MT30-31-40-41-42 series are now considered obsolete (although Allison still offers rebuilds) it can be a lot cheaper than the later MT 600 series. Heavy truck parts net it seems has quite a bit of this older stuff, although I cannot vouch for its condition.

Food for thought

David

 

Thanks for the great info , i have been looking for a donor but here in the northeast there is not much left of the old stuff. Also been looking at a bus with DD and allison, thanks again.


Mudslinger2