M39 series vs. M809 series questions on PTO and transmission

[deuceman51]

So after a little research I have found that the M809 series transmission is basically the same as the M39(M54 cargo) transmission, but with overdrive gears to better match the Cummins engine. Is there any other differences in the transmissions that a guy should know about? I have a multifuel truck that the transmission bell housing is cracked on and I have a good M809 series transmission ready to bolt in or can I change the bell housings on the transmissions? They look identical to me with the only difference I have found is on the input shaft collar. They vary by less than 1/4" in length, but of course that could make a difference. Has anybody directly swapped them out before? Also, is there any difference in the PTOs between M809 and M39 series trucks? Again, they look 100% identical to me. Transfer cases seem to be the same between the 2 series of trucks from what I have been told.

Thanks in advance!

 

[gimpyrobb]

From what I understand, it is a similar deal to the deuce transmissions. The original was non-over drive. Then they changed things inside to make it over drive.
Housings are the same.

There is a way to read the trans numbers and see what they mean, but I couldn't find it off hand.

 

[MyothersanM1]

The Spicer 6453 OD transmission (installed in M809-series trucks) superceded the 6352 non-OD and will fit any M39-series multi-fuel LDS or Mack powered truck.

 

[73m819]

You will NOT LIKE the 5t od trans, a CRAP driving transmission, it has a HOLE between 3rd and 4th that the truck can get lost in, also a hole between 3rd and 4th, just not as bad, you WILL find that you ARE lugging the engine or at topped out tack, what you can do is switch the trans adapter from one trans to the other.

 

[wilber]

I know this is an old thread, but is there a difference between the PTO's for the M54a2 and the 800 series? Thanks in advance.

 

[Evil Dr. Porkchop]

I know this is an old thread, but is there a difference between the PTO's for the M54a2 and the 800 series? Thanks in advance.

They're the same, the part number is found in the parts books for both series of trucks.

 

[fasttruck]

Reference post 4: the way to get around the "hole" between 3rd and 4th gear is to split shift the truck. 2-3-4-5 in l9ow range, then pick up high range and use 4 &5 in high. This makes 6 gears. An OD transmission will pick up about 7 miles per hour over direct drive. If you are yard running the truck this would not be a problem but topping out at 46 mph on an interstate will get you run over by the Peterbilts. Multifuels cannot be lugged so 6 gears will serve you better than 5. Had a M52A2 assigned to me in service and it had an OD transmission. I was the low bed driver so everything I moved was heavy: fork lifts, APCs, howitzers, other trucks, a 19000 pound rock once and so on. I ran that for 40,000 miles and finished up with the same clutch, transmission, u-joints and rears I started with. Watch the oil levels and lots of grease.

 

[country]

This swap will work fine

you be a little low on power building speed in 5th gear, but once you get up to cruising speed- you will really prefer it over the non-Overdrive model

 

[77 AMG]

Bump for an old thread, again. You could swap the old 6352 NON OD into an M809 be okay, correct? The truck in question has the X-case from a 900 series in it, so it would still have OD, technically. It is also on 395/85/20s' currently. My current trans is acting like it is about to go out and I have access to the old 6352 that we have, in a storage can, no less.

 

[simp5782]

Yes should be fine. if you have an input shaft size issue then they can be swapped. All spicer stuff is interchangeable

 

[kubotaman]

Bump for an old thread, again. You could swap the old 6352 NON OD into an M809 be okay, correct? The truck in question has the X-case from a 900 series in it, so it would still have OD, technically. It is also on 395/85/20s' currently. My current trans is acting like it is about to go out and I have access to the old 6352 that we have, in a storage can, no less.

Yep I know a few guys have put 6352s in M813s with 1600/20s. Can you do a thread about your conversion to the M939 type T-1138 transfer case? Love to see how you did it. Would like to do it to my M813

 

[77 AMG]

My truck was converted over to the T-1138 by another member on here.
https://www.steelsoldiers.com/showthread.php?59654-M818-Transfer-Case-Upgrade-T-138-to-T-1138
https://www.steelsoldiers.com/showthread.php?172744-Transfer-case-upgrade-to-a-XM818wouu (THIS one is actually about MY truck)