Input shaft size behind an E7, big or little ?

[John Costley]

Just curious, before I call any parts houses, to see if anyone knows if the E7s used the small input shaft like the E6s did or if they used the bigger shaft like Cat and Cummins ?. I know the FRO10s were avaliable behind the E7s because I drove a '97 CH with an E7 400 and an FRO-14210C. I've got a line on a cheap FRO-15210C, with the wide ratio spread I'm thinking it will work better behind the 237 Maxi thats in Peter J's H model instead of the RTO13 speed thats in there now. The 13 has some issues, I'd just as soon find a good used 5 or 6 speed to put behind it but its already rigged for a road ranger so it will be cheaper to stay that route. If I cant put a small input shaft on the FRO then I'll probably look around for an older RTO15 or just patch up the 13 speed. Thanks

[Ezrider]

mine has the 2"

[John Costley]

Thanks

 

[Lmackattack]

 I was not aware that there was different input sizes available on mack diesel engines?....All I had ever seen was the industry standard spline. I thought The main change needed to swap between Mack or off breed transmissions was just the bell housing so things would bolt up.  Learn something new everyday!  I would agree staying with a road ranger just for the fact that you have a Overdrive and the bell housing for it to bolt up.

[Freightrain]

Finding a transmission with the sidemount like a Mack was what I thought was the hard part.  I'd love to find something newer to put in my truck, but don't really have the room in my garage to pull the transmission and then do the fab work to get it back together.  Throw in the push clutch and it really gets complicated...so I'm told.

[John Costley]

I've never pulled one apart so I dont know first hand, but I remember conversations on different forums where it was said that the Mack sixes, E6 and older, used a 1.75 shaft instead of the normal 2.00 shaft, so to install a Roadranger would require the Mack/Eaton bell with the side mounts and a change from a 2.00 shaft to a 1.75 shaft. I took a look on the Roadranger website today, there is a 1.75 shaft kit available for the FRO series so I'm covered if I buy the FRO-15210C and end up needing it. The FRO has a lower first than the 13 and a higher OD (.74 instead of .87) so it ought to make that little 237 happy on the interstate with the 4.10 rear.

[terry]

3 hours ago, John Costley said:

I've never pulled one apart so I dont know first hand, but I remember conversations on different forums where it was said that the Mack sixes, E6 and older, used a 1.75 shaft instead of the normal 2.00 shaft, so to install a Roadranger would require the Mack/Eaton bell with the side mounts and a change from a 2.00 shaft to a 1.75 shaft. I took a look on the Roadranger website today, there is a 1.75 shaft kit available for the FRO series so I'm covered if I buy the FRO-15210C and end up needing it. The FRO has a lower first than the 13 and a higher OD (.74 instead of .87) so it ought to make that little 237 happy on the interstate with the 4.10 rear.

Worked on a lot 237 and 285 engines all had 2. inch input shafts.     terry

[Rob]

I've never seen anything with a 1.5", or 1.75" shaft from the mid 1960's and Mack Diesel myself. Earlier trucks with a TR-67 series trans, sure. Changed quite a few clutches and such over the years too. The Midliners used a metric shaft but I cannot remember the size but it was about 1.750" in diameter. 

[John Costley]

Good to know, that will make life a lot easier. Usually when I misremember something it bites me in the ass, good to know its in my favor for once, lol. Thanks

[Rob]

I'd go with a nine speed myself but that's just me. The 10 speeds are seemingly too fast for slow maneuvering to me. Given the truck never pulls anything heavier than the camper you don't need a close ratio transmission to stay in the engine torque band and I assume you're looking for a taller overdrive ratio for road speed. What model trans is in the truck now? Is it possible this new trans can use the same bell and be a slip fit without removing the clutch? I installed an RTO-12609, (IIRC) into a B-57 years ago using the Fuller side mount bellhousing, fabricating/modifying  the frame mounts from 1" plate steel. It worked well using an R model clutch setup for the pull style clutch. 

[Freightrain]

Pretty sure my Triplex is 2" input.   DW clutch sent me a dummy shaft to align when I put new clutch in.

Edited April 13, 2018 by Freightrain

[Rob]

All I've worked with are. 2" 10 spline.

[John Costley]

7 hours ago, Rob said:

I'd go with a nine speed myself but that's just me. The 10 speeds are seemingly too fast for slow maneuvering to me. Given the truck never pulls anything heavier than the camper you don't need a close ratio transmission to stay in the engine torque band and I assume you're looking for a taller overdrive ratio for road speed. What model trans is in the truck now? Is it possible this new trans can use the same bell and be a slip fit without removing the clutch? I installed an RTO-12609, (IIRC) into a B-57 years ago using the Fuller side mount bellhousing, fabricating/modifying  the frame mounts from 1" plate steel. It worked well using an R model clutch setup for the pull style clutch. 

The trans thats in it started as an RT-11509, then Peter put an RTO-12513 back half on it to get a .87 OD. First gear is 12.50, reverse is 13.07. The FRO I'm looking at has a lower first and reverse, 12.69 and 13.75, and a higher OD of .74. Its a wide ratio ten built for electronic high torque engines, the drop between gears is big enough that they dont work great with most older mechanical engine, but it should be ok behind the Maxi. Biggest reason I'm looking at it is that it should bolt straight up to the bell, though I'll need to have the shaft redone because its shorter than the 13. The kicker is that its only $300.00 and the budget is tight.