We follow Douady's approach using Cartan-Eilenberg systems, see here.
Let $B$ be a CW complex and $\pi\colon X\to B$ a Serre fibration. Put $X^k=\pi^{-1}(B^k)$. A cellular approximation~$\Delta_B\colon B\to B\times B$ of the diagonal can be lifted to an approximation $\Delta\colon X\to X\times X$ of the diagonal such that
$$X^k\stackrel\Delta\longrightarrow\bigcup_{m+n=k}X^m\wedge X^n\;.$$
Let $(\tilde h^\bullet,\delta,\wedge)$ be a reduced multiplicative generalised cohomology theory. We define a Cartan-Eilenberg system $(H,\eta,\partial)$ by
$$H(p,q)=\tilde h^\bullet(X^{q-1}/X^{p-1})$$
for~$p\le q$ with the obvious maps $\eta\colon H(p',q')\to H(p,q)$ for $p\le p'$, $q\le q'$. The corresponding exact sequences take the form
$$\cdots\to\tilde h^\bullet(X^{r-1},X^{q-1})\to\tilde h^\bullet(X^{r-1},X^{p-1})
\to\tilde h^\bullet(X^{q-1},X^{p-1})\stackrel\delta\to
\tilde h^\bullet(X^{r-1},X^{q-1})\to\cdots$$
We ignore the grading; it is easy to fill in.
To define a spectral product $\mu\colon(H,\eta,\partial)\times(H,\eta,\partial)\to(H,\eta,\partial)$ we consider the map
\begin{multline*}
F_{m,n,r}\colon(X\wedge X)^{m+n+r-1}/(X\wedge X)^{m+n-1}
\cong\bigcup_{a+b=m+n+r-1}(X^a\wedge X^b)\Bigm/
\bigcup_{c+d=m+n-1}(X^c\wedge X^d)\\
\begin{aligned}
\twoheadrightarrow\mathord{}&\bigcup_{a+b=m+n+r-1}(X^a\wedge X^b)\Bigm/
\Bigl(\bigcup_{a=0}^m(X^{a-1}\wedge X^{m+n+r-a})
\cup\bigcup_{b=0}^n(X^{m+n+r-b}\wedge X^{b-1})\\
\cong\mathord{}&\bigcup_{a=m+1}^{m+r}(X^{a-1}\wedge X^{m+n+r-a})\Bigm/
\bigl(X^{m+r-1}\wedge X^{n-1}\cup X^{m-1}\wedge X^{n+r-1}\bigr)\\
\hookrightarrow\mathord{}& X^{m+r-1}\wedge X^{n+r-1}\bigm/
(X^{m+r-1}\wedge X^{n-1}\cup X^{m-1}\wedge X^{n+r-1})\\
\cong\mathord{}&(X^{m+r-1}/X^{m-1})\wedge(X^{n+r-1}/X^{n-1})\;.
\end{aligned}
\end{multline*}Together with the diagonal map $\Delta$, for $r\ge 1$, we define
\begin{multline*}
\mu_r\colon H(m,m+r)\otimes H(n,n+r)
\cong\tilde h(X^{m+r-1}/X^{m-1})\otimes\tilde h(X^{n+r-1}/X^{n-1})\\
\begin{aligned}
&\stackrel\wedge\longrightarrow\tilde h\bigl((X^{m+r-1}/X^{m-1})\wedge(X^{n+r-1}/X^{n-1})\bigr)\\
&\stackrel{F_{m,n,r}^*}\longrightarrow\tilde h\bigl((X\wedge X)^{m+n+r-1}/(X\wedge X)^{m+n-1}\bigr)\\
&\stackrel{\Delta_X^*}\longrightarrow\tilde h(X^{m+n+r-1}/X^{m+n-1})=H(m+n,m+n+r)\;.
\end{aligned}
\end{multline*}
Proposition
For all $m$, $n$, $r\ge 1$, the following diagram commutes
$\require{AMScd}$
\begin{CD}
H(m,m+1)\otimes H(n,n+1)@>\mu_1>>H(m+n,m+n+1)\\
@A\eta\oplus A\eta A@AA\eta A\\
H(m,m+r)\otimes H(n,n+r)@>\mu_r>>H(m+n,m+n+r)\\
@V\partial\otimes\eta\oplus V\eta\otimes\partial V@VV\partial V\\
{\begin{matrix}H(m+r,m+r+1)\otimes H(n,n+1)\\\oplus\\H(m,m+1)\otimes H(n+r,n+r+1)\end{matrix}}@>\mu_1\pm\mu_1>>H_{p+q-1}(m+n+r,m+n+r+1)\rlap{;,}
\end{CD}
As explained here, this Proposition allows us to define a multiplicative structure on the associated spectral sequence.
Proof.
The upper square commutes because the maps~$F_{m,n,r}$ are defined sufficiently naturally. For the lower square, we consider the boundary morphism $\delta$ of the triple
$$(X^{m+r}\wedge X^{n+r-1}\cup X^{m+r-1}\wedge X^{n+r},
X^{m+r}\wedge X^{n-1}\cup X^{m+r-1}\wedge X^{n+r-1}\cup X^{m-1}\wedge X^{n+r},\\
X^{m+r}\wedge X^{n-1}\cup X^{m-1}\wedge X^{n+r})\;.$$
The following diagram commutes:
\begin{CD}
\tilde h^{-p}(X^{m+r-1}/X^{m-1})\otimes\tilde h^{-q}(X^{n+r-1}/X^{n-1})
@>\wedge>>
\tilde h^{-p-q}\bigl((X^{m+r-1}/X^{m-1})\wedge(X^{n+r-1}/X^{n-1})\bigr)\\
@V\delta\wedge\mathrm{id}\oplus V\mathrm{id}\wedge\delta V
@VV\delta V\\
{\begin{matrix}
\tilde h^{1-p}(X^{m+r}/X^{m+r-1})\otimes\tilde h^{-q}(X^{n+r-1}/X^{n-1})\\
\oplus\\
\tilde h^{-p}(X^{m+r-1}/X^{m-1})\otimes\tilde h^{1-q}(X^{n+r}/X^{n+r-1})
\end{matrix}}
@>\wedge\oplus\wedge>>
{\begin{matrix}
\tilde h^{1-p-q}\bigl((X^{m+r}/X^{m+r-1})\wedge(X^{n+r-1}/X^{n-1})\bigr)\\
\oplus\\
\tilde h^{1-p-q}\bigl((X^{m+r-1}/X^{m-1})\wedge(X^{n+r}/X^{n+r-1})\bigr)
\end{matrix}}
\end{CD}
We extend this diagram to the right using the maps $F_{m,n,r}$ and
conclude that the lower square also commutes.
Best Answer
A very nice generalized AHSS calculation that deserves to be better known is in
Vershinin, V. V. and Gorbunov, V. G. Multiplicative spectra that do not have torsion in homology. (Russian) Mat. Zametki 41 (1987), no. 1, 87–92, 121. [MR0886171 (88f:55012)]