Villa No 2 McAllister believes Houllier has to be allowed to bring his own signings in before any long-term judgements are made.
But the former Scotland star feels there is enough quality in the current squad for there not to need a radical overhaul.
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McAllister said: 'Give it time. The manager needs time to establish his style, his own methods, to get them ingrained in the club.
'He needs to bring his own people in but, I've got to say, there is not a great deal that needs to be added to this club.
'It is a few little tickles here and there. There are a lot of quality players here.
'We just feel in certain positions we might need a bit more experience and in other positions we might need a bit more quality.
'But it doesn't need a great deal. It just needs a little bit of tinkering.'
McAllister acknowledges the players have had to take in a lot of changes with three managers in quickfire succession and a change in training methods and playing style under Houllier.
He said: 'We are very much aware there has been a lot of change. It has been tough but to think you can come in here and make it seamless (the change) was never going to be the case.
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'People have different styles, different methods and there were three different managers in three or four months (Martin O'Neill, Kevin MacDonald and Houllier).'
McAllister added: 'The staff are still learning stuff about each other as well and we are continually still learning things about players even though we are three or four months into the job.
'You find new things all the time, how they react to bad results, how they react to being left out of the team, how they react to being put in the team.
'We are continually on a learning curve picking up bits from all the players.'
McAllister also has no doubts about the commitment to Villa of owner Randy Lerner who could not contain his emotions after the late equaliser in Sunday's 3-3 draw at Chelsea.
He said: 'Since the first day I met Mr Lerner, the thing that comes across that is apparent to myself and the manager, is he is a massive Villa fan.
'He is desperate for the club to move forward and get better and that's the major thing that comes across. He is a chairman (owner) who is a fan.'
Villa have no fresh injury worries for tonight's home clash with Sunderland although Fabian Delph and Luke Young (both knee) are again ruled out.
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