ZF Double- H Shift Pattern

ZF Double-H shift pattern

a Low range

b High range

Automatic changeover

R 2 4

1 3 5 7

6 8

N N

a b

Subject to technical change without notice.ZF Friedrichshafen AG · Lkw-Antriebstechnik · 88038 FriedrichshafenTel. +49 7541 77-0 · Fax +49 7541 77-908000 · www.zf.com/truck-transmission E

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The Double-H shift pattern has a Neutral position ineach of gates 3/4 (low range of range-change group)and 5/6 (high range).

To move the gear lever into gates 1/2 or 7/8, it mustbe pushed towards the gate against a spring force and held against this spring force while engaging thegear. The gear lever returns to the nearest Neutralposition if it is released in the middle of a gate. A stronger spring detent separates the low and highranges.

Push the lever to the right to change from low tohigh range or to the left to change from high to lowrange.

The gate for Reverse gear is protected by a spring-loaded pawl and extra force is required to overcome it.

The unequal spring forces mean that all gearpositions can be easily located in the shift pattern.

Operating ZF-Synchromesh gearboxes with Double-H shiftpattern

Double-H shift pattern

Picture: 011541

Pictures: 002690; 002691; 002692; 002693; 002694; 002695; 002696; 002697

Engaging 1st gear

Push shift lever from the 3rd/4thneutral gate against light spring,move into 1st/2nd gate and engage 1st gear.

1 – 2 Shift

When shifting from 1st to 2nd, maintain sideways pressure to the left to prevent shift lever jumping into 3rd/4th gate.

2– 3 Shift

Guide shift lever out of 2nd gear andrelease. Shift lever will spring into3rd/4th neutral gate position on itsown. Engage 3rd gear.

3 – 4 Shift

Guide shift lever from 3rd to 4thas normal.

4 – 5 Shift

Push shift lever swiftly intothe neutral gate from 4th gearand push (imp. do not guide)sideways to the right overblocking detent for the range-change group. Engage 5th gear.

Note: Range change group changesshould be carried out in one smooth operation toavoid excessive speed difference, as this increasesthe effort needed to effect gear shift.

5 – 6 Shift

Guide shift lever from 5th to 6thgear.

6 – 7 Shift

Push shift lever out of 6th gear into the neutral gate and moveinto 7th/8th gate against thespring.Engage 7th gear.

7 – 8 Shift

When shifting from 7th to 8thgear, maintain sideways pres-sure to the right or the shiftlever will spring into 5th/6thgate. An incorrect shift into6th gear may cause the engine to overrev.

Upshifts

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Subject to technical change without notice.ZF Friedrichshafen AG · Lkw-Antriebstechnik · 88038 FriedrichshafenTel. +49 7541 77-0 · Fax +49 7541 77-908000 · www.zf.com/truck-transmission

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Pictures: 002698; 002699; 002700; 002701; 002702; 002703; 002704; 002705

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8 – 7 Shift

When shifting from 8th to 7th,maintain sideways pressure tothe right or the shift lever willspring into the 5th/6th neutralgate and if 5th gear is engagedby mistake, this could cause theengine to overrev.

7 – 6 Shift

Move shift lever out of 7th and release. Shift lever will spring into5th/6th neutral gate position onits own. Engage 6th gear.

6 – 5 Shift

Guide shift lever from 6th to 5th as normal.

5 – 4 Shift

Swiftly pull shift lever from 5th into neutral gate and push (imp. do not guide) sideways to the leftover blocking detent for the rangechange group. Engage 4th gear.

Note: Range change groupchanges should be carried out in one smoothoperation to avoid excessive speed difference, as thisincreases the effort needed to effect gear shift.

4 – 3 Shift

Guide shift lever from 4th to 3rd as normal.

3 – 2 Shift

Move shift lever out of 3rd into neutralgate and pull into 1st/2nd gate against spring. Engage 2nd gear.

2 – 1 Shift

When shifting from 2nd to 1st,maintain sideways pressure to theleft or shift lever will spring into3rd/4th neutral gate and may cause an incorrect gear shift.

Reverse gear shift

Move shift lever out of 3rd/4thneutral gate across spring for 1st/2nd gate with sidewayspressure to the left and then pullfor reverse gear across springdetent. Engage Reverse gear.

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Downshifts

CAUTIONTo save wear on the transmission, alwaysdisengage the clutch fully.

• Guide the gear lever quickly but gently. It is best to guide the gear lever with the open palm of yourhand, as shown in figures at previous pages.

• When engaging a gear, hold the gear lever againstthe resistance point until the synchronizer hascompleted the gear change, then shift throughswiftly to end position.

• To move between gates 3/4 and 5/6, strike the gearlever briefly with the palm of your hand, then pushit quickly onwards into the desired gear.

Always change gear quickly; this keeps the effortrequired small. This is especially important while thetransmission oil is still cold.

If shifts are delayed, the increased levels of dragtorque when the transmission is cold cause higherdifferential speeds on the synchronizer units,requiring higher shift forces to overcome them.

CAUTION• Only engage Reverse gear with the vehicle

stationary and the engine at idling speed (pay attention to phase-out of clutch disc).

• To avoid causing severe damage to the trans-mission and engine, only change down a gear if the vehicle has been braked to below themaximum speed for the intended gear.

This is especially important when shifting downfrom the high range group at coasting vehicle.

NOTEUntil the transmission reaches its normal operatingtemperature, a greater effort is required to shift intogears. If the range-change group does not shift intothe lower range when changing down from gate 5/6to gate 3/4, brake the vehicle to a lower speed andengage an appropriate gear.

Changing gear

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ZF Double- H Shift Pattern

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