Take a Rocker Cover of and check the die casting i.d. code on the rocker arm, if it's 17,18,19 or 20 they are the old type.
If it's 13A,14A,15A or 16A they are the new type. On 1999 truck i would think they are the new type as the TSB gives a chassis range of WA382672 to WA391018.
Cheers
If it's 13A,14A,15A or 16A they are the new type. On 1999 truck i would think they are the new type as the TSB gives a chassis range of WA382672 to WA391018.
Cheers