Tranny swap fpr E9

[ws721]

Ok just to be sure. Ive been told I cant swap my 6 spd for a 13 spd behind my E9 because it has the wrong cam. So it wouldn't pull properly with a 13 spd . I find that very hard to believe but over the years I have learned to respect those who have more experience than me. Any comments?

[BAD DOG]

I've never heard that theory. I didn't know of there being any difference in stock E9 cams. I would be more concerned about a 13 SPD lasting behind an E9. I'd make sure it's a newer one with oil pump and not an antique one out of a boneyard find. I'd stick with a 15,18 or a bulletproof Mack 12 SPD. At one time Mack only sold 866 and early E9's with a heavy trans 15spd Fuller 9spd Mack or 12spd Mack,because they were heavier. I guess it all depends on what you intend on doing with the truck.

[blackdog2]

The 6 speed will take 1800 lbs torque the 12.5 13 will only take 1200 lbs unless you put a mack 9 12 13.18 speed with triple counter shaft .

[Joe Ditchkus]

You could use a 14,16 or 18 series Fuller behind the E9.In early years they used the 1200 series Fuller behind the KT 450-600 HP.Joe D.

[ws721]

Yes its a new style 13 w a pump. I was told that my E9 had a cam similar to the Maxidynes. Id keep the 6 spd because it was just rebearined @ 3000 mi ago. Just cant deal with the gap in the top 2 gears. Love it in the barnyard but out on a 2 lane road with a 45 or 50 mph speed limit it stinks. Thanks for the help.

[rsb502]

Somebody told you a fib, theres only one cam for E9's in trucks I know of, and they run awfully good with multi speed transmissions, my 84 had a Mack 12 speed, my 85 has an Eaton RTX 14609 9 speed that im planning on swapping to a 13 or 18 speed when I can. The swap from a Mack trans to a Mack trans would be easier, if you put in an Eaton youll need to swap the trans bellhousing more than likely and either way youll have to shorten the front section of your driveshaft.

[felicello122]

That big 13 will be just fine in there, like joe d said they used the older 13 behind those big kt and v8 cats and the v-12's.

[rsb502]

My 85 has a 14609 I know Im making more than 1400# of torque and its still going so far, Im gonna put whatever 13 or 18 I can find over a 14 series in it, I could kill an 18 series but if you drive it right youll be ok.

[ws721]

Lol. Thank yoy for the reply. Next question im pondering is gear ratio. I currently have 5.73s. Tranny has a .73 overdrive. I do not haul heavy any more and If need to I have other truck with a hood that I don't mind overworking. No its not a Mack. I was thinking 3.87s but after following the comments on here from you folks im kinda leaning toward 4.17s. Thanks again for the info.

[rsb502]

What size tires are you running and what do you want to do with your truck? I have 3.65 rears in mine with 11R24.5's and its a little high for heavy haul. I think Ill go to 3.86-4.17 but again I have 11R24.5 tires if your running 11R22.5's then a 3.87/3.86-3.65 would work well, if tall 24's then probably 3.87-4.17 just depends on weight really, that and your expected average road speed. I try to run 68 or so and it puts me around 1400rpm with 3.65 rears and tall 24.5's, 4.17's will raise it 200rpm, 3.86's will be about 100 rpm, with my .74OD.

[ws721]

Has 22.5 at the moment but I want to put hub piloted w 24.5 lo pro's. They just look cleaner than the spokes. Pulling a dropdeck hauling farm machinery and hay. So not much weight. Does 1400 rpm give you good mileage? I was aiming for @ 1500 rpm at 70 mph

[rsb502]

well low pro 24.5's and 11 r 22.5's are the same height so no change there, for 1500 rpm youll need 3.86/3.87 with the low pro, I get around 6.5 what Ive checked, my 84 stayed in the 6.4-6.8 range with 4.42 rears.

[ws721]

1. Ok. Thanks. Im getting 6.1 now with the 6spd at a .62 overdrive and 5.73 rears. I don't consider that to terrible for a COE. I just want more gear choices! On a 45 to 50 mph 2 lane road it really stinks. Its either tached out or lugging @ 1100 rpm. Got to see what the Mack Museum paper work says. Gentleman on the phone told me Mack only made 95 Cruiseliners with theE9. I bet im still going to change it. Just to make it more driver friendly truck

[j hancock]

5.73 w .62 over is a 3.55 ratio.

5.73 w .73 over 4.18 ratio.

4.17 w .73 over 3.04 ratio.

3.87 with an E9.......LOOKOUT!

[ws721]

Wow. That is interesting. Ok, now im really going to test you folks. With the 13 spd that has a 12.31 low would idle around a barnyard ok? That's the only time I like the 6 spd. Other than when someone challenges me at a red light. The 6 spd is good there too

[j hancock]

Mack X107A 6 speed is 14.43.

Should give similar results.

[rsb502]

Your low will be lower than the Eaton trans, an 8LL,15 or 18spd has 14.40 low gear, other than that its in the 12's. What makes you say the E9 isn't very driver friendly, I like em better than most other engines. If your gonna do something for driveability swap to a Mack 12 speed or a 13/18 speed and rock on. I'm pretty sure you'll want to swap to some higher rears after you do I'd go with the 4.17 for what you are wanting to do. Oh and you'll still have a freakin E9, and that worth a lot.

[bobo]

If you want lower LOW, get your 13spd back box rebuilt into a 18spd. Your low/low will now be 14.4 and still have a low of 12.3 bobo

[terry]

I have never heard of a E9 mated up to a 6 speed, wwas this done by a previous owner?

[2stacksuperdog]

I have never heard of a E9 mated up to a 6 speed, wwas this done by a previous owner?

I was wondering that too. I know they mated them to the 866s but not usual with a E9.

[rsb502]

If you want lower LOW, get your 13spd back box rebuilt into a 18spd. Your low/low will now be 14.4 and still have a low of 12.3 bobo

Um actually the back box is the same on a 13/18 speed, the difference is the fact that you "can't" use deep reduction in low range to get the 14.40. However you can swap the shifter or just pop the plastic stop out of the 13 speed shifter to select deep reduction in low range giving the same low gear. However in an Eaton the gears and bearings in the front box in low range are different than those in an 18 speed,they're bigger for more torque capacity.

[2stacksuperdog]

Why do they put a plastic stopper in there? just give the extra gear so if you want it you have it.

[rsb502]

Its because of the lower torque capacity of the gears and bearings in low range, Eaton can build a 13speed cheaper than an 18. I asked an Eaton rep about 2 or 3 years ago at MidAmerica why they didn't just make the 18 and sell it with either shifter as a 13 or 18 convertible. He told me they made it cheaper by using the 9 speed components for low range and heavier components for high range to handle the split so it was both cheaper and lighter to build a 13. I asked how much cheaper and lighter and he couldn't answer than question, all the info I could find showed a 15-20# difference in the 13 and 18 speed Eaton.

[theakerstwo]

If it a RTLO then 13 and 18 is same weight

[rsb502]

Yeah it makes no sense to me but they say its different, I'd swap the shifter and run the 13 like an 18 since you would rarely use the deep reduction in low range, I like splitting the top two gears more than anything.