I have a dana 44 front axle that i got off of a parts truck and i cant find any information on it. The Bill Of Materials number on it is 610040-4 and there is no ratio tag bolted to the diff. cover. it also has a 44-9f on the webbing.

from what ive read around the net so far, it looks like it is a dana 44hd out of a 78-79 f250. but i cant find a decoder that will tell me exactly if that is true. i also really need to know the gear ratio. does anyone know how to find that?

I tried turning a tire 1 revolution, and counting how many times the u-joint turns but it only turns a little over 2 times. something i did was wrong because i cant imagine they would have made a 2.something to 1 gear ratio. do both tires need to be spinning?

anybody have a way to decode this BOM or maybe know of an easy way to figure out the gear ratio? thanks

 

The little metal tag has been removed because the cover has been off at some point or another, and never replaced. It could have been left off intentially because the ratio has been changed.
The only sure fire way to determine the ratio in it now, is to remove the 10 bolts holding the inspection cover to the axle. This is what the onspection cover is for.
remove it and inspect the ring gear for some numbers that are stamped into the edge.
This will tell you the count for the ring gear and the pinion. Divide the ring by the pinion to determine the ratio.
This is a great time to inpesct the gear condition, as well as to determine whenther or not this axle has a traction device or not.

Do not rely on numbers to verify the ratio. Take a few minutes to verify the 100% correct way.

If this axle is a 78/9 front axle, then it is a HP, not an HD axle. This axle is not considred HD, and does not carry the HD designation that the earlier axles did.

Just a run of the mill, high pinion Dana 44, with open knuckles, and disc brakes. Nice enough axle, and great axle to use as a replacement for early axles with drum brakes.

 

thank you for the reply, this helps greatly. i will go outside right now and check that out. and thanks for the info on the hp and hd. i will post the gearing shortly. thanks again

 

ok, i just checked it out. looks like 4.09 gear ratio. there was a 45-11 on there which im assuming are the numbers you are referring to.

there was also some other things stamped on the ring gear:

12 6 77 DANA 33850 a3d6 45-11

12 6 77 i believe is the date

DANA is self explanatory

dont know the other ones

 

also, thats the first time ive ever opened up a differential. how do i tell if its an open diff. or trac loc or anything else? i took a picture but i cant figure out how to load it. thanks

 

 

Std open carrier. No treaction devices there at all.
Oil is not in the bst of shape either. That could stand a chaninging.

 

thanks for the knowledge. much appreciated!

 

BOM #610040-4 decodes as a 1978 F-250 Dana 44,4.09 ratio,open case. Was used with both full-time and part-time transfer cases...

 

ford 6.02005:

thanks for the decoding, i couldnt find it anywhere, how did you find that information? i have a few more axles that i dont know anything about. is there a book or something i can buy somewhere?

and with the info from 75f350, i was able to figure out the gearing on 2 of my other axles very quickly. thanks guys

 

After 10 years working in a 4x4 specialty shop and saving a set of Spicer books from that era I still look them up the old fashioned way-you may want to try www.spicerparts.com and navigate your way through their site...or If you post your BOM#'s I will be glad to look them up!

 

oh wow, sound like some good books to have. ok, if you're alright with it. i forgot to write down one of them but here's a weird situation. I have a 1970 f100 that was pieced together with allll different year parts.

now i looked at the front axle and it looks like someone even pieced that together too because on the tubing it has the BOM: 610049-7 but there is a tag on the diff. cover that says 603781-9.

and when i checked out the ring gear it had a date of 1975 i believe and it had 3.50 gear ratio. Once 75f350 told me about people taking off the tags for a reason i figured that maybe they put this tag on for a reason.

 

Tubing BOM#610049-7 shows 1978.5 F-150 Dana 44 3.50 ratio open case. Tag BOM#603781-9 shows 1976-1977 F-100&F-150 Dana 44 3.50 ratio open case.Ring & Pinion gearsets have different part numbers on these two BOM numbers-I suspect one of them is reverse bevel?For sure the 1978.5 is reverse.The tag is probably there to show gear ratio only??

 

Both of those axles mentioned will be of the reverse cut, or reverse spiral design.
Only the F250 axles of this era had low pinion designs.

 

so i checked out that spicer parts website. thats a great site to look all this up. thanks! i see what you're saying about the ring and pinion gear kits.

it is kinda weird that they are both 3.50 gear ratio with open diff. and both reverse spiral cut (basically the same exact ring and pinion) but they have two different kit numbers. because it seems that all the other kit numbers are the same if they are the same gear ratio and same cut.