Spit Balling LOL

[Nothing Special]

Ford F834 wrote

.... it is a little rough starting out uphill so I use the transfer case low range....

Ford F834 wrote

.... 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.

For what it's worth, "they" say that you can't shift a transfer case between low and high while you are moving.  Obviously it's possible, and if you know what you're doing with the clutch and matching gear speeds it doesn't need to be hard on the transfer case.  But for "just anybody" reading this, using the transfer case as a granny gear to get started is not recommended.

[Ford F834]

Nothing Special wrote

For what it's worth, "they" say that you can't shift a transfer case between low and high while you are moving.  Obviously it's possible, and if you know what you're doing with the clutch and matching gear speeds it doesn't need to be hard on the transfer case.  But for "just anybody" reading this, using the transfer case as a granny gear to get started is not recommended.

You are exactly right, and the faster you are going the less it will want to shift from low range to high range on the fly. It’s worse than non-synchronized first, but neither one go smoothly while rolling. T-case low range can get you out of a jam or get you to a flatter spot to take off in high range though.

[Nothing Special]

Ford F834 wrote

.... T-case low range can get you out of a jam or get you to a flatter spot to take off in high range though.

And I'm sure you know this but for other's benefit, low range 2WD is great for moving trailers around the yard or driveway too.  A lot less clutch slipping (or a lot less throttle with an auto trans) so it's easier to control.

[FuzzFace2]

All good information.
If I was to add a 4x4 Tcase I would do a full 4x4 swap but don't really need 4x4 down here like up north.
I also would not be towing the trailer all the time so if setup better for not towing would be the way to go with this truck.
I just don't want to run a higher first gear OD trans than what I have now with the T18 2nd gear, I drive it now as a 3 speed.
Dave ----

[FuzzFace2]

Gary got me going back to this with his Calculator page http://www.garysgaragemahal.com/calculators.html
and having fun with numbers.
I got to say the speedo & tach are spot on in my truck (300 six / t18 / 2.75 gear) as I have checked the speed with a GPS shortly after I fixed the speedo gears and just yesterday on the way home was able to see the mile posts, cant do that at 2am in the dark! The mileage is also spot on so a few more tank fills and I should have a good idea of MPG. At 70 MPH & 29" tire I run about 2300 RPM.

So with the information given it looks like I will be looking for a M5-R2 from 88 - 91 small block trucks, if I get lucky maybe a ZF but will not hold my breath.

Right now my granny gear is 17.38 (6.32x2.75=17.38) that is to low with out a load.
2nd gear is 8.50 (3.09x2.75=8.495) and is a little to high for my liking.

The M5-R2
first with my 2.75 rear gear would be 10.73 (3.90x2.75=10.725)
That is good for normal driving but with a load is not so good.
With other rear gear numbers:
3.90x3.08=12.01 is better  
3.90x3.25=12.675 is better yet but wonder if maybe to low with out a load?

But starting out in 2nd gear, 2.25
3.25x2.25=7.31 is even worst than my T18 of 8.50 is now so no 2nd gear starts unless we go a lot lower in the axle and that defeats the over dive at that point.

So Over Drive what numbers do we get? (RPM @ 70 MPH)
Stock now 1.1x2.75=2.75 (2300 RPM) (RPM @ 65 MPH 1507) (RPM @ 45 MPH 1435)
.80x2.75=2.20 (1784 RPM)
.80x3.08=2.464 (1999 RPM)
.80x3.25=3.60 (2110 RPM)

The thing to keep in mind is this is for a low revving straight six and the numbers I have are
carb: 120hp @ 3000 RPMs / 255tq @ 1400 RPMs

So from what I see the M5-R2 with my 2.75 gear is a good starting place and if I was to do a gear swap a 3.08 would be good for the lower first gear load pulling when needed but not so low to be like the T18's granny and I get a good OD ratio with both the 2.75 & 3.08 where and 3.25 only gets me a little lower than what I have now with the T18 & 2.75.

Also this will not pull the trailer all the time, it is a back up when needed and so far in the almost 5 years down here I have only used the trailer to bring the 2 trucks home and that was like 6 months after we got here.
Dave ----

[Gary Lewis]

Dave - Later today I'll see if I can put the new section in the Calculators page.  Maybe that will help you make your decision?

[FuzzFace2]

Gary Lewis wrote

Dave - Later today I'll see if I can put the new section in the Calculators page.  Maybe that will help you make your decision?

No rush for me as it will be sometime before I will do this swap and based on what has been posted looking for a small block ZF is like the needle in the hay stack and the M5 does not look all that bad when I ran the (total or final) numbers for the gear ratios.
Dave ----

[Rembrant]

FuzzFace2 wrote

So from what I see the M5-R2 with my 2.75 gear is a good starting place and if I was to do a gear swap a 3.08 would be good for the lower first gear load pulling when needed but not so low to be like the T18's granny and I get a good OD ratio with both the 2.75 & 3.08 where and 3.25 only gets me a little lower than what I have now with the T18 & 2.75.

Dave,

I'm running the M5-R2 with 3.08 gears, but my tires are lower profile...I believe 28" OD. I find it geared a tiny bit on a tall side, but it's perfectly fine for what I do with the truck. I don't haul anything, and the little 302 is built up a little bit. I think it's right around 2000 RPM at 65-70 MPH...I don't remember exactly where it was.

I really like the trans, and I'm hoping for some good MPG numbers when I can finally get testing it again in the spring. I bought a spare trans a while back...it was local-ish and cheap-ish (at $150) so I grabbed it. It's pretty grungy looking, but it was my plan to rebuild it when I run out of other rehab projects.

[Gary Lewis]

Go check it out.  Is that what you were looking for?  If not, what did I miss?  http://www.garysgaragemahal.com/calculators.html

[FuzzFace2]

Rembrant wrote

FuzzFace2 wrote

So from what I see the M5-R2 with my 2.75 gear is a good starting place and if I was to do a gear swap a 3.08 would be good for the lower first gear load pulling when needed but not so low to be like the T18's granny and I get a good OD ratio with both the 2.75 & 3.08 where and 3.25 only gets me a little lower than what I have now with the T18 & 2.75.

Dave,

I'm running the M5-R2 with 3.08 gears, but my tires are lower profile...I believe 28" OD. I find it geared a tiny bit on a tall side, but it's perfectly fine for what I do with the truck. I don't haul anything, and the little 302 is built up a little bit. I think it's right around 2000 RPM at 65-70 MPH...I don't remember exactly where it was.

I really like the trans, and I'm hoping for some good MPG numbers when I can finally get testing it again in the spring. I bought a spare trans a while back...it was local-ish and cheap-ish (at $150) so I grabbed it. It's pretty grungy looking, but it was my plan to rebuild it when I run out of other rehab projects.

Cory I was hopping you would see this and I remember you saying your setup was geared a little high.
I was also thinking you have a 302 that is a higher revving motor for the HP & TQ than my stock low revving 300 and then you built it up and that would make it a little higher still.

Would you know, of course you know, what your 302's HP & TQ is at what RPM's?
I would like to see how it compares to a stock 300 as that can tell how well the 300 will like a M5-R2 transmission.
BTW I don't remember did you do the trany swap before or after the built up motor?
Dave ----

[FuzzFace2]

Gary Lewis wrote

Go check it out.  Is that what you were looking for?  If not, what did I miss?  http://www.garysgaragemahal.com/calculators.html

Yes that works just took me a bit to find what the change was LOL (I am slow)
Maybe a little blurb on the right side with the over drive information that it shows up in the "Overall Gear Ratio"?
Now to go play more
Dave ----

[Rembrant]

FuzzFace2 wrote

Cory I was hopping you would see this and I remember you saying your setup was geared a little high.
I was also thinking you have a 302 that is a higher revving motor for the HP & TQ than my stock low revving 300 and then you built it up and that would make it a little higher still.

Would you know, of course you know, what your 302's HP & TQ is at what RPM's?
I would like to see how it compares to a stock 300 as that can tell how well the 300 will like a M5-R2 transmission.
BTW I don't remember did you do the tranny swap before or after the built up motor?
Dave ----

Hi Dave,

I did the tranny swap and motor at the same time. I had the engine dyno tested, but the dyno didn't start reading until 2800 RPM, so I don't really know what the numbers are below that point. It made 335 TQ at I believe around 3100RPM, and before the build up I believe factory spec for TQ was around 250, in the same RPM range. It was my HP that took a big jump from the factory spec of about 135 to 300, but that was at 5000+ RPM.

Ford did build the trucks with the M5-R2 and 3.08 (and taller) gearing, so it's not like it's a custom set-up by any means. Actually, the truck my trans came out of was a 1991 F250 with a 302 and I assume 3.08 gears. The speedo cable drive gear in my trans is specifically for 2.75-3.08 diffs, and my spare M5-R2 is the same as well, so it was a common configuration.

I shouldn't say that I find the gearing all that tall. I guess what I should be saying is that it isn't geared low. It feels pretty normal to me, like any other manual trans pickup from the 90's when 5spds were still common. The ZF5's were in the heavier trucks, and I've never really driven them, so I don't really have anything to compare to.

[FuzzFace2]

Cory,

Thanks for the feed back I was hopping to compare the 2 different transmissions with the same motor but not going to happen LOL

Using Gary's gear calculator (my tire size of 235/75/15=28.9" tall) you went from a
3sp of 10.04 first gear ratio (3.26x3.08=10.04)
to
5sp of 12.01 first gear ratio (3.90x3.08=12.01)

So first gear is lower, not by much, for a better take off from a stop.
You do end up with a OD final of 2.46 and at 65 MPH puts you at 1863 RPM.
That is way below where your motor now makes any power and why you say it is geared to high.

That is why I think my 300 6 would be a great fit for the M5-R2 5sp as my HP & TQ are down lower in the RPM range and even better if I went with 3.08 gear set.

We also have to remember manf. were trying to get the most MPG out of everything back then and their thinking was to get the RPM as low as you can.
A lot of cars & trucks were dogs back then because of the small motors, another way to get low MPG and the gearing.
Thanks again.

My plans may change.
The T18 is hurting, PITA to shift with out grinding, and needs to be rebuilt or swapped out for something else. Would love a 5sp with over drive but I might have found a NP435 from a 86 truck for a little more money than what a rebuild kit goes for the T18.

Going over gear ratios I see the NP has a lower granny but also a lower 2nd gear than the T18 and that would make it easier to start off in 2nd and drive it like a 3sp like I do the T18.
I still end up with the same 1:1 4th as my T18 but if the transmission is in good shape we can add an OD unit to it.
Just waiting for a reply for the person on what all he has then I can work out a deal for it and some parts he may have.
Dave ----

[Rembrant]

FuzzFace2 wrote

You do end up with a OD final of 2.46 and at 65 MPH puts you at 1863 RPM.
That is way below where your motor now makes any power and why you say it is geared to high.

Yes, exactly...it's a little tall for the 302 if you're just cruising at 65 MPH and hit a hill. Almost guaranteed to have to down shift. If I'm over 2000 RPM it's much better, but I'm also going faster and have more momentum to get up the hills. Problem is, I just don't drive at 75MPH. The good thing is that 4th is still 1:1, which is exactly what it was before, do down shafting isn't drastic or anything.

On flat ground though, the 5spd is nice. The 302 doesn't have much power below 2000 RPM, so it's a bit of a dog there. If it's up around 2500 RPM, it pulls very nicely, but I'm talking 4th gear...I don't think I've ever hit 2500 RPM in 5th.

[FuzzFace2]

Rembrant wrote

FuzzFace2 wrote

You do end up with a OD final of 2.46 and at 65 MPH puts you at 1863 RPM.
That is way below where your motor now makes any power and why you say it is geared to high.

Yes, exactly...it's a little tall for the 302 if you're just cruising at 65 MPH and hit a hill. Almost guaranteed to have to down shift. If I'm over 2000 RPM it's much better, but I'm also going faster and have more momentum to get up the hills. Problem is, I just don't drive at 75MPH. The good thing is that 4th is still 1:1, which is exactly what it was before, do down shafting isn't drastic or anything.

On flat ground though, the 5spd is nice. The 302 doesn't have much power below 2000 RPM, so it's a bit of a dog there. If it's up around 2500 RPM, it pulls very nicely, but I'm talking 4th gear...I don't think I've ever hit 2500 RPM in 5th.

That is what I was thinking , RPM up where the 302 likes it and no problem.
I have been watching my tach & speed to see how well the 300 pulls at a RPM / Speed.
I was around 600 or 700 and about 20 MPH think 3rd maybe 4th as it is hard to shift between them, and it pulled pretty good.
Pulls even better at 1000 RPM so I know mine should pull good at lower RPMs than the 302.

I have also find a NP435 from a 86 that is a little more money that the rebuild kit. The 2nd gear is a little lower than my T18 and that is good when driving it like a 3sp like I do the T18. Checking a few things if it is a bolt in other than drive shaft. It is little over 6 hours away and if it fits the wife & I will make a weekend and see family when I pick it up.
Then see if the banker will "loan" money for Advance Adaptor OD unit.
Dave ----

[1986F150Six]

Cory and Dave,

For whatever it is worth, I would not worry about the 300/4.9L being able to handle the ratio ranges being discussed. Ford offered a 2.47 rear end with 4 speed manual OD [0.71].

My truck has 3.08 rear gears with 4 speed manual OD [0.71]. At 55 mph, it is @ ~1535 RPMs; @ 65 mph, the RPMs are ~1810 PMs.

These engine speeds are right in the "sweet spot" regarding the engines torque. It will maintain the speed with no problem.