  We perform an OPE analysis of the flavorless non-perturbative gluon
propagator and the symmetric three-gluon vertex in the Landau gauge. The first
subdominant operator is $A_\mu A^\mu$ which can condensate in the Landau gauge
``vacuum'' although being a non-gauge invariant operator. We neglect all higher
dimension operators. Then the gluon propagator and the symmetric three gluon
vertex only depend on one common unknown condensate. We propose a consistency
check from lattice data. At two loops for the leading coefficient and with
$1/p^2$ corrections at tree-level order the two fitted values for the
condensate do not agree. At three loops we argue that the today unknown
$\beta_2^{\rm MOM}$ should be equal to $1.5(3)\times \beta_2^{\widetilde{\rm
MOM}}=7400(1500)$ to fulfill the OPE relation. Inclusion of the power
corrections' anomalous dimensions should improve further the agreement. We show
that these techniques cannot be applied to the asymmetric three gluon vertex
with one vanishing momentum.
