1990 GMC Suburban service bulletins & manufacturer communications

4 manufacturer communications are on file with NHTSA for the 1990 GMC Suburban. TSBs are repair guidance for dealers — they are not recalls, and repairs are not automatically free.

• Diagnosis of cracked or broken transmission case. *tt 2006 and prior cars and light duty trucks. *tt
  020730024A · Technical service bulletin · Power Train · issued Aug 1, 2005
• Diagnostic information for intermittent transmission downshift, slip, busy/cycling tcc or noisy cooling fan. *tt
  990730016A · Technical service bulletin · Power Train · issued Oct 1, 2002
• COLD ENGINE KNOCK. *TW
  376105 · Technical service bulletin · Engine and Engine Cooling · issued Feb 1, 1995
• New cast iron exhaust manifold and stainless steel gasket to correct engine noise condition. *tw
  376602A · Technical service bulletin · Engine and Engine Cooling · issued Jan 1, 1995