| Subject: | Manual Transmission Neutral Rattle |
| Models: | 2007-2008 Chevrolet Kodiak, T-Series |
| 2007-2008 GMC TopKick, T-Series |
| 2007-2008 Isuzu F-Series, H Series |
| 7500/8500 Series with 7.8L Diesel Engine (RPO LG4/LF8) |
| and Manual Transmission (RPO MK8 (7 spd) / MUT (9 spd) / MS9 (9 spd) / MT3 (10 spd) |
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:
The "neutral gear rattle" with the Isuzu 7.8L diesel engine and manual transmission is a normal operating characteristic as referenced in Information Bulletin #03-07-29-004B.
Recommendation/Instructions:
The neutral gear rattle noise condition (with the Isuzu 7.8L diesel engine and manual transmission) can usually be minimized by increasing the base engine idle speed by 50 to 100 RPM. It is necessary to use the Isuzu IDSS diagnostic system to raise the
7.8L engine idle RPM.
Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.
