Converting Low Speed Transmission To Taller Gearing?

[David Dunn]

Well, if the obvious wasn't the problem, working down the list... (cheapest things first ... the emergency brake is released? then all the service brakes are adjusted ( there are 2 adjusters on each of the front wheels) ? Brake lining have been known to shatter and wedge themselves in. Was the previous owner a submariner? Playing in water and mud will play absolute hell on the Pinz's brakes if not cleaned, especially the emergency brake discs.
Next (you should have already done as a new owner), check fluids in all the gearboxes and portals. For some reason, some people don't pay attention checking and maintain. I can't believe the number of trannies I've heard of that were driven to the point of not being rebuildable due to not having oil.

The engine does run well? Revs easily and without hesitation?
And as suggested earlier, put your location in your profile, besides someone is possibly near you, your local climate condition also helps to diagnose things.

[Jimm391730]

Again, just to check: you said your truck runs fine through all the gears - all FIVE gears? if the shift linkage gets far enough out of wack, you might not be getting fourth and fifth if the shifter is hitting the air tunnel and preventing its motion to the far right... just on the off chance that you are going through gears one to three, missing 4 and 5... the Heim joint at the transmission end of the shift linkage often falls apart when worn out, and can make the shifting very sloppy.

[dieseltoy]

Yes, all fluids were changed before I did any driving, as well as the tires and axle boots (dry rotted).
No sign of water contamination, or excess heat on the drivetrain or wheels after a 20mi drive. Rolls easily in neutral, so I don't think the brakes are stuck.
4th and 5th are louder than the other gears.
Shifts through all five gears, but does feel sloppy.

Also, the speedo only reads up to 70 km/h.
Here are a couple pics (looks stock to my untrained eye).

[dieseltoy]

lads

let me contribute the gear ratios



The 5 speed gearbox is a ZF S5-18/3 used in several vehicles of the 70 and 80ies.
Maybe you can find a box that fits your needs.

The only ones that seem close are the

Volvo C306
1st gear 3.92
2nd gear 2.47
3rd gear 1.76
4th gear 1.27
5th gear 1.00

Or possibly the

Iveco Daily 35.8
1st gear 6.000
2nd gear 3.650
3rd gear 2.040
4th gear 1.300
5th gear 1.000
R-gear 5.470

(I am probably missing other candidates)

Thanks for your help!

[rmel]

Well there's one simple and fool proof thing you can try.

Put your Pinz in what you believe to be 5'th gear and
X-case in H position. Lockers and 4X4 OFF, put in neutral,
and emergency brake OFF. Block your front tires

Raise one rear tire off the ground.

Chalk mark on bottom of tire off the ground
Chalk mark on bottom of "shorty" drive shaft.

Turn the drive shaft 5 3/4 revolutions. Your tire should have
gone slightly more than one complete revolution. If less
then your 5'th ain't a 5'th, or maybe your X-case is a swap
with a 712 (but that alone would not explain the speed difference
your experiencing). But you can figure that out easily knowing
where your tire clocked to and then calculate.

This will at least take all the mystery out of the drive train.

ron

[dieseltoy]

Thanks Ron!
Gonna give that a try in the next day or two when time permits, and I will report the findings.
(the t-case reads "4x4" above the number tag, you can just barely see it in the photo)

[Jimm391730]

The Volvo and Iveco transmissions have exactly the same high gear (5th) ratio of 1.00:1 (input shaft directly connected to output shaft) so they won't get you going any faster than the stock transmission (and it looks like that's what you have from the photos). Ron's test will check the transfer case, diffs and hubs for their expected ratio, but the drive shaft will only need to be rotated 2-7/8 rotations since the differential action will double the raised tire rotation speed since the opposite tire is still on the ground.

Another test: Put the transfer case in neutral and the transmission in 5th. Mark the crank pulley and the output flange on the transmission. Rotate the engine crankshaft one revolution; the output of the tranny should also move the same amount since it should be a 1:1 ratio in 5th. In 1st the crank will need to rotate 5.33 revolutions for one revolution of the tranny output and so on for the other gears. You can prove (or disprove) that you have the stock transmission with this test.

If these come out right then you just have to squeeze the skinny pedal further! You should also check to see that the pedal opens the throttles all the way, about 90 degrees. I have seen the throttle linkage get stuck and not operate fully.

[rmel]

Oops! Forgot about the diff multiply with one leg lifted.

Well you could also leave the tire on the ground, tie
a string to the drive shaft, push truck forward one tire
revolution then count the number turns the string took
up on the drive shaft. Eliminates the jack part

[Hotzenplotz]

The german Pinzgauer forum has a thread about the varations of the ZF gearbox

they list the usage of the ZF S5-18/3 gearbox for the following vehicles

transmission ratio

Alfa Romeo Montreal
1. Gang 3,418
2. Gang 1,941
3. Gang 1,389
4. Gang 1,000
5. Gang 0,795
R-Gang 3,663


Iveco Daily 35.8
1. Gang 6,000
2. Gang 3,650
3. Gang 2,040
4. Gang 1,300
5. Gang 1,000
R-Gang 5,470


Volvo C306
1. Gang 3,920
2. Gang 2,470
3. Gang 1,760
4. Gang 1,270
5. Gang 1,000
R-Gang 3,700


Pinzgauer TD (neues Modell ab 1985)
1. Gang 4,250
2. Gang 2,510
3. Gang 1,480
4. Gang 1,000
5. Gang 0,747
R-Gang 4,030


Pinzgauer Benziner (altes Model bis 1985)
1. Gang 5,330
2. Gang 3,240
3. Gang 2,050
4. Gang 1,300
5. Gang 1,000
R-Gang 5,470


Opel Kadett 1900 LS
1. Gang 2,990
2. Gang 1,760
3. Gang 1,305
4. Gang 1,000
5. Gang 0,874
R-Gang ?

[edzz]

Yes, all fluids were changed before I did any driving, as well as the tires and axle boots (dry rotted).
No sign of water contamination, or excess heat on the drivetrain or wheels after a 20mi drive. Rolls easily in neutral, so I don't think the brakes are stuck.
4th and 5th are louder than the other gears.
Shifts through all five gears, but does feel sloppy.

Also, the speedo only reads up to 70 km/h.
Here are a couple pics (looks stock to my untrained eye).

70 km/h speedo? Most I've seen indicated (were marked for) up to 100 or 120 km/h, any chance your speedo face has been changed out for a mpg face? Have you verified the speeds you are indicating with a gps?

Also hard to tell in the photos however I don't see any evidence of recent grease in the drive shaft and u-joints.

[TechMOGogy]

Good catch on the speedo!
dieseltoy - Post a picture of it please

[dieseltoy]

It was 2-7/8 rotations with one wheel lifted, so mystery solved there.

I think a tach is in order (and an oil pressure gauge) but not familiar with the options for these items so thanks for any opinions.

The trans sounds like the loudest part of the drive train by far. 1st gear seems too low for normal street driving so maybe a td trans would be a better choice.

The shifting seems very sloppy. Probably due for a rebuild.
Looking forward to meeting up with other owners in the future to get some educated opinions.

Thanks for any help!

Here is a pic of the speedo

[TechMOGogy]

That has to be a mph speedo no?
The orange speed pointers almost match up (within a few mph compared to kph)
Here is mine

C776B698-C052-4146-96A7-B397CC011E69.jpeg (885.59 KiB) Viewed 7421 times

[edzz]

re: Sloppy shifting, first thing is to replace the banjo bushings. Replacing these bushings may remove a surprising amount of slop and prevent being stranded if one fails. Since you'd be placing an order get new throttle linkage end pieces, they are typically plastic and prone to failure if they have never been replaced. Ordering an extra of each for your field emergency kit isn't a bad idea.

viewtopic.php?f=12&t=7290&p=52148&hilit ... ing#p52148

Most people do not use first gear unless starting out up hill. And yes the trans is loud even in perfect condition, part of the gear design.

The speedo's on these trucks often are in need of refurbishment and/or are out of calibration. Many owners convert to electronic speedos or just use a GPS. Many of the Garmin units (not all) are 24v friendly.

[dieseltoy]

That has to be a mph speedo no?
The orange speed pointers almost match up (within a few mph compared to kph)
Here is mine

C776B698-C052-4146-96A7-B397CC011E69.jpeg

It says kp/h, but it has the 90* cable adapter on the back so it's probably not accurate

Probably going to go GPS as Ed suggested.