39/809 clutch suggestion

[73m819]

For you that have HEAVY 39/809 series 5ts (wreckers, ect.,) here is a BETTER way to shift to save the clutch. As you KNOW the trans suck especially the overdrive, though the non-overdrive is not much better. The wreckers are close to the 36,000 lb. mark, loaded can be a easy 60,000, the trans has a hole between 3rd and 4th that the whole truck could fall in, 2nd to 3rd has a hole but about 1/2 as bad. The clutch is a SINGLE disk, the trans puts to much load on a single disk (should be a DOUBLE) when taken the load, which REALLY shortens the LIFE of it in HI. The way I found to get around the crap trans and a single disk at the same time is to start out in 2nd L, then 3,4,5 low, then drop from 5 to 4th, shifting to HI at the same time, then 5th. BY doing this the starting load on the clutch is GREATLY reduced, ALSO the BIG hole between 3rd and 4th is about gone. This may take some practice, but after a bit shifting will have NO missed shifts and be as smooth as (you fill in the blank), You WILL notice a difference for the good. This is just a suggestion, try it, if you like it GOOD, not like it, nothing lost.

 

[Scar59]

Yeah, if you have two right arms.... Seriously, good info Ron, my 813 rarely has much weight. The 3-4 hole does bug me
when trying to get up to speed quickly.

 

[simp5782]

Ive got some carbide ceramic puck clutches Ron. I just need an old disc to rebuild as a core.

 

[gimpyrobb]

We've been shifting like that in our deuces with heavy loads for a while. Welcome to the light.

 

[162tcat]

For you that have HEAVY 39/809 series 5ts (wreckers, ect.,) here is a BETTER way to shift to save the clutch. As you KNOW the trans suck especially the overdrive, though the non-overdrive is not much better. The wreckers are close to the 36,000 lb. mark, loaded can be a easy 60,000, the trans has a hole between 3rd and 4th that the whole truck could fall in, 2nd to 3rd has a hole but about 1/2 as bad. The clutch is a SINGLE disk, the trans puts to much load on a single disk (should be a DOUBLE) when taken the load, which REALLY shortens the LIFE of it in HI. The way I found to get around the crap trans and a single disk at the same time is to start out in 2nd L, then 3,4,5 low, then drop from 5 to 4th, shifting to HI at the same time, then 5th. BY doing this the starting load on the clutch is GREATLY reduced, ALSO the BIG hole between 3rd and 4th is about gone. This may take some practice, but after a bit shifting will have NO missed shifts and be as smooth as (you fill in the blank), You WILL notice a difference for the good. This is just a suggestion, try it, if you like it GOOD, not like it, nothing lost.

This is the way I shift in my M817 when loaded. You almost have to unless your headed down hill or on flat ground.

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[74M35A2]

6 speeder.

 

[someoldmoose]

Saw this yesterday and didn't have time to reply. Good tip but I thought everyone did this as S.O.P. Guess using the clutch pedal just for starting and stopping unless some unusual situation occurs is how I learned 100 years ago ( and THOSE trannys were NOT synchronized ). I did use it bringing "baby" home more than I ever would have in my ancient truck tractor but once I know her song I probably won't use it for "normal" shifting.

I definitely agree about the gear spacing. I suspect these were not shifted much in their "normal" working environment. Highway miles were probably limited and cross country was probably handled mostly with the low side of the T-case ( hence a top speed of 25 in 5th ) Anyway, your point is VERY valid. BE KIND TO YOUR CLUTCH.

 

[73m819]

We've been shifting like that in our deuces with heavy loads for a while. Welcome to the light.

I have been shifting like this for years since I lost my last clutch, just got around to posting about it, in fact I "think" I have posted before on this, but in case not I posted .

 

[73m819]

A twin and a tri stick is what I learned to drive a BIG REAL truck, not a WANT-A-BE truck with a auto trans,. 36 gears behind a 200 Cummins or a DD 671 = 3 sticks, this was what was needed for a heavy haul truck, and at times NO PS but some had clutch assist because the clutches were BIG double or triple disks. without assist you knew WHAT a hard clutch peddle was.

 

[simp5782]

Didn't know the flintstone mobile was a 3 sticker. Ha!

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[74M35A2]

I don’t know how you guys do all that fandangled stuff. I can’t even count to 3.

 

[porkysplace]

A twin and a tri stick is what I learned to drive a BIG REAL truck, not a WANT-A-BE truck with a auto trans,. 36 gears behind a 200 Cummins or a DD 671 = 3 sticks, this was what was needed for a heavy haul truck, and at times NO PS but some had clutch assist because the clutches were BIG double or triple disks. without assist you knew WHAT a hard clutch peddle was.

And the Macks with them were in a league of their own.

 

[dmetalmiki]

Hmmm..12 years good clutch no wear..I just have >that feel< (and) treat my trucks 'carefully'.
Or.....Do 'nowt in a rush!. (as they say in south east Barnsley!.( min'st 'that car at the top of the hill VERY Nearly got -rushed!!))
https://youtu.be/6cwjK46Il_4

 

[dmetalmiki]

And that was pulling a full load. RPM's and changes always the same, NO over reving..My M62 has always (and still) does the job. OK..not in a rush..but it does it.

 

[74M35A2]

...and:

https://m.youtube.com/watch?v=8lEYaTvvq4g

 

[74M35A2]

https://m.youtube.com/watch?v=Tas59JfTrt4

 

[162tcat]

Is there a more heavy duty clutch available? I work my 817 pretty hard so its only a matter of time. I'm considering swapping to the direct drive 5th gear trans to help out with the big 3-4 hole too. With 16.00' s I should still be in the 50+ mph range.

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[71DeuceAK]

I am bookmarking this! As someone who has literally been learning to drive stick in M809 series 5 tons.

 

[someoldmoose]

71Deuce,
I hope I'm not speaking out of turn but shifting a 5 ton that is empty is "easy". This thread is more about when the rig is being used at or near max. capacity. If you've never driven with a manual trans. then yes, there is a learning curve involved but the bigger curve is learning to judge these things "position in the universe" while moving. Mine, for example, has a turning RADIUS of nearly 50 feet. I have turned tractor-trailers (with pig trailers) around in less space than my M820.
I was VERY surprised when I learned that the transmission in my beast is synchronized (except for 1st and reverse). I learned to shift with the diagram in 74M35A2's post, three sticks, Strongarm steering, AND double clutching (until I learned how tuh not to). Compared to that, shifting one of these is no different than a Toyota Celica.

 

[AMGeneral]

A twin and a tri stick is what I learned to drive a BIG REAL truck, not a WANT-A-BE truck with a auto trans,. 36 gears behind a 200 Cummins or a DD 671 = 3 sticks, this was what was needed for a heavy haul truck, and at times NO PS but some had clutch assist because the clutches were BIG double or triple disks. without assist you knew WHAT a hard clutch peddle was.

That's exactly what I started driving a class 8 truck in as well Ron, a 1964 B-67 Mack w/a Theromdyne, no P/S, and a quadbox.

I haven't moved up much thus far as my current Mack is a 69 R model, with a 237 and a Duplex, still no P/S.