<PAGE>   1
                                  EXHIBIT 10.8

                                 AMENDMENT NO. 4

                                       TO

                              SEPARATION AGREEMENT

THIS AMENDMENT NO. 4, dated March 21, 1995, is between PACIFIC TELESIS GROUP
("Telesis") and AIRTOUCH COMMUNICATIONS, INC. on behalf of itself and on behalf
of AIRTOUCH COMMUNICATIONS OF CALIFORNIA ("PacTel").
        
WHEREAS, there is currently in full force and effect between the Parties a
Separation Agreement, effective October 7, 1993, as modified by Amendments No.
1 dated November 2, 1993, No. 2 dated March 25, 1994 and No. 3 dated April 1,
1994 (the "Agreement"); and
        
WHEREAS, the Parties wish to make certain additional clarifications to the
Agreement;
        
THEREFORE, the Parties agree that the Agreement is hereby amended as follows:

1. Section 5.4.c of Appendix C (Intellectual Property) is amended to read as
follows:
        
         "c. The license term of the Licensed Marks will expire two years after
         the Separation Date. If PacTel adopts the New Name prior to two years
         after the Separation Date, then until September 1, 1995 and except as
         provided below, PacTel will be permitted to use the tagline "the new
         name for PacTel" in connection with the New Name. PacTel will cease all
         use of the word "PacTel" in taglines as of 12:01 a.m. on September 1,
         1995.

         Notwithstanding the above, PacTel agrees to cease using the tagline
         "the new name for PacTel", as of 12:01 a.m. on April 15, 1995, in
         connection with the following:


<PAGE>   2


         (1) All advertising including, but not limited to, print, radio,
         television, any electronic media (including, but not limited to, online
         services), outdoor and direct mail, but excluding collateral and
         product packaging; provided, however, that PacTel shall change its
         yellow pages advertising and other such advertising that can only be
         changed annually at the first available opportunity after April 15,
         1995;

         (2) all correspondence, including letterhead, envelopes and business
         cards, reports, filings, newsletters, brochures, presentation
         materials, fax cover sheets and other communications sent to the
         financial community including, but not limited to, brokers, analysts
         and portfolio managers, individual investors and regulatory agencies;
         and

         (3) all communications with shareowners including, but not limited to,
         quarterly and annual reports, proxy statements, correspondence and the
         like.

         The parties agree that PacTel shall cease using the tagline "the new
         name for PacTel" in connection with collateral and product packaging as
         of 12:01 a.m. on September 1, 1995.

         Nothing in this provision shall require PacTel to recover leased
         equipment from customers in order to remove the Licensed Marks provided
         that PacTel uses reasonable measures to remove the Licensed Marks
         before leased equipment is re-leased by PacTel to PacTel's lease
         customers after PacTel has adopted its New Name."

2. PacTel shall use its best efforts to comply with the terms of this Amendment
No. 4, it being understood that isolated, inadvertent uses after the above dates
of documents, such as a piece of letterhead containing the tagline, shall not
constitiute a breach of this Amendment No. 4 or the Agreement.

3. Except as expressly amended by this Amendment No. 4, the provisions of the
Agreement shall continue in full force and effect.

                            (Signature page follows)


<PAGE>   3


IN WITNESS WHEREOF, the Parties have caused this Amendment No. 4 to be executed

PACIFIC TELESIS GROUP                  AIRTOUCH COMMUNICATIONS, INC.
                                       on behalf of itself and on behalf of
                                       AIRTOUCH COMMUNICATIONS OF
                                       CALIFORNIA

By:  /s/ Phil Quigley                  By:  /s/ Sam Ginn
   --------------------------             ---------------------------

Title: Chairman, President             Title: Chairman of the Board and CEO
and CEO

Date Signed: March 29, 1995            Date Signed: March    , 1995