Spit Balling LOL

[FuzzFace2]

But the Mazda tranny has a first gear ratio of 3.9 vs the T18’s 6.32. So it won’t be nearly as easy to get a load started.

I think that is the very reason he wants the ZF5 gear box.

The Mazda tranny gets a bit of a bad rap in my opinion, but there's no denying that it is a much lighter transmission. In my truck with the 3.08 rear diff, the gearing is really tall, and you can feel it pulling away in first gear. Ford did sell them with this gearing combo, so I didn't do anything unusual here...but it's definitely a light duty set-up, certainly more geared towards fuel efficiency than towing.

I think with 3.55 or 3.73 diff gears, the Mazda trans would be much better to work with in a "work" truck. I've seen a lot of guys around here put snow plows on these F150's, and I assume that would be as torturous on the truck as trailer towing, if not worse...lol.

Thanks guys for the information gives me a lot to think over.

Yes the lower (granny gear) of the T18 is nice for getting heavy loads moving and not burning up the new clutch.

Could go with the M5-R2 higher first gear and a lower rear gear to get the first useable but need to run the numbers to see what the final ratio comes to.

I say this also based on what was posted that a ZF5 might be hard to find for a 4x2 small block as they most likely be used in the F250> trucks so could not use the suspension as planed but not a deal breaker.

So this brings up another question on the M5-R2 & ZF5 transmissions, I have not searched this yet, How to tell the difference between them when looking at them?

I would guess the ZF would have a cover for the PTO where the M5-R2 may not?

Some of the ZF's I have seen on the inter web had a plate saying ZF but what if it is missing?

I don't want to do I think what Happen to Cory and looking fro a ZF and when found one it was the M5-R2but again if that is all I can find I may go that route.

Does the M5 have the same rap of the ZF that the syncros could be worn and make it hard to shift or it is a lot better in that regard?

Now to go back and re-read this post and all the links / data to get a grip on the information over load LOL

Thanks

Dave ----

added: On the shifting, yes I drive a big rig and to tell the truth it shifts better than the T18 in my truck now. I the work truck you float the gears only using the clutch for starting & stopping. I find myself starting to do the same in the pick up and that don't turn out so good LOL

So a "truck shifting" ZF is not a big deal to me as long as it shifts as my T18 does not want to do all the time.

I also hear you on looking for 2 trucks for the needed parts would be easier than 1 as for the way they were built.

Right now the transmission is top on the list.

thanks

[Rembrant]

I don't want to do I think what Happen to Cory and looking fro a ZF and when found one it was the M5-R2.

Hey Dave,

I was always looking for an M5-R2, but I kept missing one that was only a mile away because the guy had it listed for sale as a ZF5. Once he realized his mistake, he relisted it and then I grabbed it right away. It was funny in the sense that it was for sale down the street for a month and I didn't even know;).

The M5-R2 does not have a PTO cover. It's pretty easy to identify though. It is a little smaller than the ZF5, and it has a long tail shaft like a typical transmission. It also has a slip yoke. Here's a picture of mine below:

The part number on the transmission data tag will tell you what speedo cable drive gear it has also.

Now I am no expert on the ZF5, but it is a bigger chunk of a transmission with a very square back end and a fixed yoke. Here's a picture I snagged from Google.

 

[1986F150Six]

I don't want to do I think what Happen to Cory and looking fro a ZF and when found one it was the M5-R2.

Hey Dave,

I was always looking for an M5-R2, but I kept missing one that was only a mile away because the guy had it listed for sale as a ZF5. Once he realized his mistake, he relisted it and then I grabbed it right away. It was funny in the sense that it was for sale down the street for a month and I didn't even know;).

The M5-R2 does not have a PTO cover. It's pretty easy to identify though. It is a little smaller than the ZF5, and it has a long tail shaft like a typical transmission. It also has a slip yoke. Here's a picture of mine below:

The part number on the transmission data tag will tell you what speedo cable drive gear it has also.

Now I am no expert on the ZF5, but it is a bigger chunk of a transmission with a very square back end and a fixed yoke. Here's a picture I snagged from Google.

Nice work, Cory.

[Ford F834]

I don't want to do I think what Happen to Cory and looking fro a ZF and when found one it was the M5-R2.

Hey Dave,

I was always looking for an M5-R2, but I kept missing one that was only a mile away because the guy had it listed for sale as a ZF5. Once he realized his mistake, he relisted it and then I grabbed it right away. It was funny in the sense that it was for sale down the street for a month and I didn't even know;).

The M5-R2 does not have a PTO cover. It's pretty easy to identify though. It is a little smaller than the ZF5, and it has a long tail shaft like a typical transmission. It also has a slip yoke. Here's a picture of mine below:

The part number on the transmission data tag will tell you what speedo cable drive gear it has also.

Now I am no expert on the ZF5, but it is a bigger chunk of a transmission with a very square back end and a fixed yoke. Here's a picture I snagged from Google.

The ZF in Rembrant’s picture is a big block or diesel external slave ZF. The small block ZF with internal slave looks similar but with a different bellhousing:

There is usually a plate on the driver side that gives the manufacturing date and the gear ratios. However some rebuilders remove the plate so it is often missing.

According to the documentation, it looks like it was offered in F150’s... but I have never seen one. Only F250/350. If I were looking for a F150 with a ZF I would look at F150’s with a 351W. Just a hunch because of the higher output.

The Mazda 5-speed won’t have as low of a start out gear, but the gears are closer together and the straight six will like that. I’m amazed at how much nicer mine does with the close ratio T19 compared to the wide ratio granny T18’s or NP435 that have been behind my other sixes.

How much weight do you need to get rolling? For reference, my truck has 3.00 gears. The diesel T19 has a 4.02 first gear. My final drive ratio in 1st is 12.05 to 1. I have 31.72” diameter tires. With a 275 gallon water tank in the bed it starts out with ease (~2,300 payload). With the 28’ 1960 Streamline camper it is a little rough starting out uphill so I use the transfer case low range. The literature on our trailer says the curb weight is 4,200 lbs. our example is likely well into the 5,000’s with modernizations and extra junk. I’m completely impartial here, just trying to lend some real world experience that may help you make a decision. You can factor in your tire size to see how my set up compares to the options you are looking at. With my tire size I don’t feel like I need much more overdrive gear, given the not very flat topography in my area I am happy with it, and glad for a third gear that isn’t such a huge jump down when I need to downshift. You could always get a 4x4 transmission and transfer case and only use it for a creeper gear. It could also help you get a cable speedometer since it drives off of the transfer case and any older t-case could be used.

[Nothing Special]

I thought I had the information saved but cant find it

The truck this will go on is a 81 F100 2WD flare side, 300 six, w/T18 and 2.75 9" rear gear.

The T18 needs some help, wore out and does not shift well. I could rebuild it but I would not have over drive but I like the granny low for heavy loads and it will be a back up for pulling my car trailer....

"Granny low" and "overdrive" are very subjective terms. With your 2.75 axle ratio and T-18 your final drive ratio is 2.75:1. Compare that to the 2.92:1 final drive ratio I have with my E4OD trans in overdrive coupled to my 4.10 axle gears and you already have a taller overdrive than I do! Similarly, the close-ratio 4 speed in my '75 CJ5 had almost as low a "granny low" as your T-18 when coupled to the 4.27:1 rear axle it had.

So if you change to an "overdrive" trans, with or without a "granny low", you can really dial in whatever you want with the axle ratio.

One good way to look at the ability of a trans to offer a "granny" gear and an "overdrive" is to look at the overall spread. Your T-18 has a 6.32:1 1st gear and a 1:1 4th, so the total spread is 6.32. An M5-R2 has a 3.9:1 1st and a 0.8:1 5th, so the total spread is only 4.88 (that's 3.9 / 0.8, not 3.9 + 0.8). So you could go to 4.46 gears with an M5-R2 and have about the same "granny gear" as your T-18, but not as tall an "overdrive" as you currently have. Or a 3.44 gear ratio would give you the same "overdrive" but not as low a "granny" (not that exactly those ratios are actually available).

With a wide ratio ZF5 (which I think was most common), the 5.72:1 1st and 0.76:1 5th give you a total spread of 7.53, just a little wider than your T-18. With that trans 3.62 axle gears would give you about the same "overdrive" but a slightly deeper "granny". Or 3.04 gears would give you the same "granny" with a taller overdrive.

What you really gain with a 5 speed trans is another gear in the middle, so you don't have to wind it out as high before lugging it down as low on shifts. Also synchros in all gears and, in the case of the M5-R2, a smoother shifting trans. But you'll get ratios in a different place, so you may need to change your axle ratio to really take advantage of it.

(By the way, if you get a close ratio ZF5 you're looking at 4.14:1 1st and 0.77:1 5th, so a total spread of 5.38, a little wider than the M5-R2 but not quite as wide as your T-18.)

 

[Ford F834]

I thought I had the information saved but cant find it

The truck this will go on is a 81 F100 2WD flare side, 300 six, w/T18 and 2.75 9" rear gear.

The T18 needs some help, wore out and does not shift well. I could rebuild it but I would not have over drive but I like the granny low for heavy loads and it will be a back up for pulling my car trailer....

"Granny low" and "overdrive" are very subjective terms. With your 2.75 axle ratio and T-18 your final drive ratio is 2.75:1. Compare that to the 2.92:1 final drive ratio I have with my E4OD trans in overdrive coupled to my 4.10 axle gears and you already have a taller overdrive than I do! Similarly, the close-ratio 4 speed in my '75 CJ5 had almost as low a "granny low" as your T-18 when coupled to the 4.27:1 rear axle it had.

So if you change to an "overdrive" trans, with or without a "granny low", you can really dial in whatever you want with the axle ratio.

One good way to look at the ability of a trans to offer a "granny" gear and an "overdrive" is to look at the overall spread. Your T-18 has a 6.32:1 1st gear and a 1:1 4th, so the total spread is 6.32. An M5-R2 has a 3.9:1 1st and a 0.8:1 5th, so the total spread is only 4.88 (that's 3.9 / 0.8, not 3.9 + 0.8). So you could go to 4.46 gears with an M5-R2 and have about the same "granny gear" as your T-18, but not as tall an "overdrive" as you currently have. Or a 3.44 gear ratio would give you the same "overdrive" but not as low a "granny" (not that exactly those ratios are actually available).

With a wide ratio ZF5 (which I think was most common), the 5.72:1 1st and 0.76:1 5th give you a total spread of 7.53, just a little wider than your T-18. With that trans 3.62 axle gears would give you about the same "overdrive" but a slightly deeper "granny". Or 3.04 gears would give you the same "granny" with a taller overdrive.

What you really gain with a 5 speed trans is another gear in the middle, so you don't have to wind it out as high before lugging it down as low on shifts. Also synchros in all gears and, in the case of the M5-R2, a smoother shifting trans. But you'll get ratios in a different place, so you may need to change your axle ratio to really take advantage of it.

(By the way, if you get a close ratio ZF5 you're looking at 4.14:1 1st and 0.77:1 5th, so a total spread of 5.38, a little wider than the M5-R2 but not quite as wide as your T-18.)

Unfortunately there never was a close ratio ZF for the small block bellhousing. It was for diesel bolt pattern only and no interchangeable bell. I have heard talk of main case swaps, but the input shaft is smaller on the small block ZF, and that’s not something that swaps without machine work. Like I said, I’ve heard talk, but no verification that anyone has ever done it. It would be a great gear set for the straight six, but the M5OD is similar to it if you can live with the lighter duty gear box.

The point about gear spread and axle ratios is a good one. People hear that I have 3.00 gears and balk at it, wondering how I can stand it, and how I am able to haul anything. Well for years I drove 4.10 geared F250’s with T18’s. I rarely used granny 1st gear, like, almost never... I drove them as a three speed with final ratios of roughly 12, 7, 4. With my diesel T19 the ratios are roughly 12, 7, 4, 3. It’s basically like my 4.10 geared trucks were but with “overdrive” instead of a creeper gear.

Before switching to 4x4, I had basically what FuzzFace2 has. A 2.75 rear and T18, sitting on worn 31” tires that measured 29” actual. I didn’t like this. 2nd gear starts were rough and hard on the clutch. Starting out uphill meant using the very clumsy 1st that was way too low and non synchronized. I didn’t drive it much before converting to 4x4, because a front wheel bearing was bad. I can’t comment on the final 2.75 ratio except that I lost a bit on top going to 3.00 gears, but I went up in tire diameter at the same time so it was a wash. I can drive 80mph but 62-67 is the sweet spot. On the highway it would be nice to have a bit more on top (overdrive), but with my 4x4 weight (4,200 lbs) and wind drag the terrain would have to be pretty flat to use more than the 3.00 that I have. David/1986F150six has 3.08’s plus overdrive on smaller wheels. He is geared taller than mine and it works very well, but his son’s 2.75 with overdrive was unlikeable enough that he regeared it.

[FuzzFace2]

Unfortunately there never was a close ratio ZF for the small block bellhousing. It was for diesel bolt pattern only and no interchangeable bell. I have heard talk of main case swaps, but the input shaft is smaller on the small block ZF, and that’s not something that swaps without machine work. Like I said, I’ve heard talk, but no verification that anyone has ever done it. It would be a great gear set for the straight six, but the M5OD is similar to it if you can live with the lighter duty gear box.

The point about gear spread and axle ratios is a good one. People hear that I have 3.00 gears and balk at it, wondering how I can stand it, and how I am able to haul anything. Well for years I drove 4.10 geared F250’s with T18’s. I rarely used granny 1st gear, like, almost never... I drove them as a three speed with final ratios of roughly 12, 7, 4. With my diesel T19 the ratios are roughly 12, 7, 4, 3. It’s basically like my 4.10 geared trucks were but with “overdrive” instead of a creeper gear.

Before switching to 4x4, I had basically what FuzzFace2 has. A 2.75 rear and T18, sitting on worn 31” tires that measured 29” actual. I didn’t like this. 2nd gear starts were rough and hard on the clutch. Starting out uphill meant using the very clumsy 1st that was way too low and non synchronized. I didn’t drive it much before converting to 4x4, because a front wheel bearing was bad. I can’t comment on the final 2.75 ratio except that I lost a bit on top going to 3.00 gears, but I went up in tire diameter at the same time so it was a wash. I can drive 80mph but 62-67 is the sweet spot. On the highway it would be nice to have a bit more on top (overdrive), but with my 4x4 weight (4,200 lbs) and wind drag the terrain would have to be pretty flat to use more than the 3.00 that I have. David/1986F150six has 3.08’s plus overdrive on smaller wheels. He is geared taller than mine and it works very well, but his son’s 2.75 with overdrive was unlikeable enough that he regeared it.

Thanks guys,

I would say my trailer with car is close to 5000lb, car is 3000+ and the deck of trailer is 21' and I have a tool box and tire rack up front.

Because it is pretty flat around here I also drive my T18 / 2.75 / 28" or 29" tire as a 3 speed and with just the truck, no load, its not bad from a start.

I will look for the ratios for the ZF & M5-R2, have them for the T18, so I can play with the numbers.

Would be nice to get a transmission with a first a little lower than the T18 2nd gear and little above the granny of the T18 and have OD would be nice.

I did find a wrecked 88 F150 with a newish 302 not far from me but don't know what transmission it has and cant reply to the add to ask. I might hunt it down to check it out as it may have hurt the motor / drive line it get hit so hard.

Dave ----

[Gary Lewis]

Thanks guys,

I would say my trailer with car is close to 5000lb, car is 3000+ and the deck of trailer is 21' and I have a tool box and tire rack up front.

Because it is pretty flat around here I also drive my T18 / 2.75 / 28" or 29" tire as a 3 speed and with just the truck, no load, its not bad from a start.

I will look for the ratios for the ZF & M5-R2, have them for the T18, so I can play with the numbers.

Would be nice to get a transmission with a first a little lower than the T18 2nd gear and little above the granny of the T18 and have OD would be nice.

I did find a wrecked 88 F150 with a newish 302 not far from me but don't know what transmission it has and cant reply to the add to ask. I might hunt it down to check it out as it may have hurt the motor / drive line it get hit so hard.

Dave ----

Dave / The ratios and the ability to change things are in the calculator here: http://www.garysgaragemahal.com/calculators.html.

[FuzzFace2]

Dave / The ratios and the ability to change things are in the calculator here: http://www.garysgaragemahal.com/calculators.html.

Thanks when I have more time, family is here for the holiday, I will check it out better.

Dave ----

 

[Ford F834]

Dave / The ratios and the ability to change things are in the calculator here: http://www.garysgaragemahal.com/calculators.html.

Thanks when I have more time, family is here for the holiday, I will check it out better.

Dave ----

Dave, I am going to throw out a couple of thoughts/suggestions... things that you might want to keep in mind while running the math.

If you keep you 2.75 rear gears, I would say skip the overdrive transmission. Even the mildest overdrive (.80 on the M5OD) puts you at 2.20 final drive ratio. In my opinion and experience with my truck, that would be too much. David 1986F150six is at a 2.40 final ratio, ask him what he thinks, if 2.20 would work out. My 3.00 is “equivalent” to ~2.82 on stock tire size listed on the door sticker. I think 2.20 would be very weak and might hurt rather than help mpg. If you do overdrive, I would say get at least a 3.08 or stouter 9” chunk to go with it. 3.25 or better if you get a ZF with .76 overdrive.

The other thing that was huge for me, going to the close ratio transmission was the first downshift (into 3rd). The close T19 goes from 1:1 to 1.41 which is perfect, especially while towing. When I can’t hold it in direct drive, 3rd lands right in the straight six’s sweet spot, not wound out like it is with the wide ratio T18’s etc., it’s like direct drive with a 4.10 truck, not sidelined with emergency flashers going... the M5OD is 1.49 which is a little lower but not 1.69 like the T18’s. I can tow all day in 3rd like overdrive cancel button on a U-Haul.

Since you need to pull a 5,000 lb trailer I think you need at least a 12:1 first gear. My set up is maybe a little hard on the clutch, but works just fine if it’s not day in and day out. Main thing is it’s hard to get going uphill. If you needed to start from a dead stop on a 8% grade you might be in trouble. That’s why I suggested a 4x4 transmission and T-case. It’s not elegant, but it is an affordable solution to a crawl gear for those occasions when you need it.