1690 HS: In need for speed chart from manual.

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Posts: 245
Joined: Thu Jul 20, 2006 8:50 pm
Location: Everdingen, The Netherlands

1690 HS: In need for speed chart from manual.

Post by Dieter » Fri Aug 01, 2014 8:35 am

Hi fellow DB enthousiasts,

Can someone help me with the speed chart which includes figures for the total reduction ratio of the chosen gear combination, for a 1690 HydraShift model?
This chart is normally in the manual.

In the 1490 manual I have, the overall reduction is mentioned in the speed chart, but in the 1694 manual, there is a speed chart as well, but not with overall reduction ratio's :( .

As the gears in both Hydrashift planetary unit and the range box are different when you compare a HS gearbox from a 4 cylinder tractor to a 6 cylinder, I would like to know the reductions for a 6 cylinder HS gearbox.

Reason for this is, I have some parts laying around and would like to know more about it, so I can combine these parts in order to get a driveline best suited for my needs.

I'm not talking about speeding up my tractor to 50km/h or something, so please no comments about improving brakes, or that DB were not designed for 40+ km/h, just thinking about tractorpulling at the moment.

I suspect the ratio's of the HS planetary units on a 6 ylinder box lay closer together, so the difference in engine speeds will be less when changing up/down, which can be an advantage of a 6 cylinder box.
I would like to experiment with that, but have to change reductions also in order to get a proper total reduction.

Therefore I'm asking for a the speed chart where also the total reduction ratio is mentioned, for a 1690 HydraShift.
- A good scan or photo from the needed page would help me a lot, anyone willing to make one?

Thanks in advance!

Best regards,

Posts: 280
Joined: Sun Jan 01, 2006 12:01 pm
Location: Acquoy, Netherlands.

Post by Anne » Fri Aug 01, 2014 11:58 am

Hey Dieter,

According to the Case-IH part site, the planetary units of 4 and 6 cilinders seems to be the same. The range box otherwise is different. A quick scan on the partlist of both range boxes gives the following numbers:

1th gear: 46 teeth
2th gear: 36 teeth
3th gear: 24 teeth
Reverse: 43 teeth

1th gear: 38 teeth
2th gear: 30 teeth
3th gear: 22 teeth
Reverse: 43 teeth

By the way, differential crownwheel / pinion ratio seems also to be different comparing 14 and 15 series.

Hope this is any help to you.. :)

gr. Anne
-DBTC member-
1969 DB 780 Selectamatic -
1981 DB 1190 Cab -
1985 Case IH 1494 Hydrashift 4wd -
1988 Case IH 1394 Synchro 4wd Comm. Edition -
2011 Case IH 1494 Tractorpulling Edition 250 HP!
1985 Case IH 2294 4wd 160hp

Posts: 245
Joined: Thu Jul 20, 2006 8:50 pm
Location: Everdingen, The Netherlands

Post by Dieter » Fri Aug 01, 2014 12:19 pm

Hey Anne,

Thanks for your input.

I've compared the rangeboxes on the Case-IH website as well, and
- all 4 cylinder modells, except the 1412, have the same rangebox.
- 1594 and 1690 also have same range box.
- 1412 is a one of a kind, with a range box of its own, but quite similar to the other 4 cylinders:
1st: 46
2nd: 36
3rd: 25 or 26
R: 43

The planetary units on 4 cylinder, 1412 and 6 cylinder modells use the same clutch packs, but they have different planet gears in them, when comparing the partsnumbers on the website.
According to the info I have, the gearboxes on 6 cylinder modells run at higher revs, in order to be able do cope with more power, without increasing shaft thickness, gears, bearing etc.
(Torque x revs = power. If you increase the revs, you don't need heavy duty components in order to handle more power.)
I'm interested if this increase in speed is done only in the range box, or also in the HS planetary units.
It seems to me the reduction ratio's in the planetary unit on a 6 cylinder are smaller than on a 4 cylinder modell, resulting in gears which 'lay closer together'. Some sort of Hydrashift close ratio gearbox :)

Crown pinion wheel:
- 4 cylinder except 1412: 7/43 (not checked on Case website, but thought I read this on this forum)
- 1412: 8/41
- 6 cylinder: 8/43 (not checked on Case website, but thought I read this on this forum)

Would like to see if I can create a sort of close ratio HS box with the parts I have, to see if that will work better for pulling than a standard 4 HS cylinder box :)

Vr. Grt. Dieter

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